https://mdotwiki.state.mi.us/construction/api.php?action=feedcontributions&user=HarrisR18&feedformat=atomMediaWiki - User contributions [en]2024-03-29T14:39:22ZUser contributionsMediaWiki 1.35.2https://mdotwiki.state.mi.us/construction/index.php?title=E-Signature&diff=3956E-Signature2015-03-05T13:55:38Z<p>HarrisR18: </p>
<hr />
<div><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Division 1 Supplemental Information'''</span></center><br />
<center><span STYLE="font: 30pt arial;">'''e-Signature'''</span></center><br />
<br />
<br />
====[[#General Information|General Information]]====<br />
<br />
According to the Code of Federal Regulation, electronic signatures are defined as a computer data compilation of any symbol or series of symbols executed, adopted, or authorized by an individual to be the legally binding equivalent of the individual's handwritten signature. A specific type of electronic signature is digital signatures. Digital signatures are defined as an electronic signature based upon cryptographic methods of originator authentication, computed by using a set of rules and a set of parameters such that the identity of the signer and the integrity of the data can be verified. <br />
<br />
An entity such as a computer user can be assigned a unique digital identification. This digital identification is composed of a public key, a private key, and a digital certificate. As their names suggest, the public key should be shared amongst users who wish to carry out transactions amongst themselves, while the private key should be only known by its user. The digital certificate is used within a public-key infrastructure to allow a third-party certificate authority to verify that the digital certificate is correctly associated with that particular public key.<br />
<br />
As public keys are shared amongst a group of users, someone’s public key can be used to encrypt a document and their respective private key can be used to decrypt that document. Confidentiality and data integrity of the sent document can be practically guaranteed assuming if the recipient is the only one who knows their private key. Similarly, someone’s private key can be ‘embedded’ into a document to constitute an electronic signature, and the identity of the electronic signature may be verified by using that user’s public key. <br />
<br />
{{top}}<br />
<br />
====[[#Adoption at MDOT and Acceptable Uses|Adoption at MDOT and Acceptable Uses]]====<br />
The Michigan Attorney General’s office, in concurrence of the Federal Highway Administration, has issued a decision authorizing the Michigan Department of Transportation (MDOT) to use and accept digital signatures (see [http://www.michigan.gov/documents/mdot/MDOT_IM12-02_378056_7.pdf BOH IM 2012-02]).<br />
<br />
There are many standards available for digital signatures, but MDOT currently authorizes the use of PKCS#12 files for digital identification. This cryptographic standard requires the signer to enter their unique password each time they digitally sign a document. To digitally sign a document, you must first have a digital identification (ID). This ID can be obtained from various certification authorities, but MDOT will primarily use Adobe as a certification authority. [http://www.michigan.gov/documents/mdot/Setting_Up_an_Electronic_Signature_422066_7.pdf This PDF file] and [http://www.youtube.com/watch?v=pUIWvJgkw8E this YouTube video, produced by Adobe Acrobat,] shows how to create a digital ID on Adobe Reader.<br />
<br />
Digital signatures created with Adobe Software need to conform to the following style guidelines: <br />
*Graphic options shall be:<br />
**“Name” Or “Imported Graphic” (as outlined below)<br />
<br />
*Configure text shall be configured as:<br />
**Uncheck the adobe “logo”<br />
**Required to include: (“Name”, “Date”, “Location” and “Reason”)<br />
**Optional “Distinguished Name” (includes job title)<br />
**Optional for “labels”<br />
**“left to right”<br />
You may have multiple digital signature files configured for different purposes. It is even possible to configure a digital signature with an “Imported Graphic” (refer to this [http://www.michigan.gov/documents/mdot/Applying_an_Image_To_Digital_Signature_422061_7.pdf PDF]) containing an image of your scanned written signature or a scan of a professional license stamp. These are acceptable, but written signature images are not required and non-business related graphics are not acceptable.<br />
<br />
Similar to how handwritten signatures must be verified, it is the responsibility of the recipient of a electronically signed document to confirm the identity of the signer/sender before the electronic signature may be considered valid. The recipient should consider whether or not that the document was sent from a recognized e-mail account and that the expected signer has been previously validated. If you are unsure, then you can verify by contacting their place of business. Adobe Acrobat software has an integrated validation feature that stores validated signatures, meaning that the user does not need to validate those signatures again. This [http://www.michigan.gov/documents/mdot/Trusting_and_Validating_a_Digital_Signature_422068_7.pdf PDF] shows how to validate a signature.<br />
<br />
MDOT is working on integration of electronic signatures on mobile devices. There are several mobile applications that allow PDF files to be digitally signed using mobile devices, but as of now none have been authorized for employee use. Employees are encouraged to submit mobile applications to the E-Sign team of the Construction Field Services Division and to the Department of Technology, Management and Budget. This [http://www.michigan.gov/documents/mdot/How_To_Add_A_Digital_Signature_Via_iPhone_422065_7.pdf PDF] shows how to digitally sign a PDF file on an iPhone.<br />
<br />
It is important to note that for records retention and archiving purposes whenever digital signatures are used on documents, the electronic file (usually PDF) is considered the original legal document. Printouts of the document containing digital signatures are considered copies, so the signed electronic file must be retained and follow the relevant approved records retention procedures. MDOT will address the records storage issue through the requirement that all electronically signed documents must be placed in the project directory in the ProjectWise document management program. The E-construction [http://mdotwiki.state.mi.us/construction/index.php/E-Construction wiki page] contains more information regarding ProjectWise. <br />
{{top}}<br />
<br />
====[[#Guidance for Non-MDOT Users|Guidance for Non-MDOT Users]]====<br />
<br />
An individual’s digital signature must be validated before MDOT can accept the signature. [http://mdotcf.state.mi.us/public/webforms/public/5600.pdf Form 5600] for contractors and [http://mdotcf.state.mi.us/public/webforms/public/5600A.pdf Form 5600A] for consultants allows an individual to submit their digital signature to MDOT. When you select the signature box when filling out these forms, you can use an existing digital ID or you can create a new ID. There are many ways an individual can obtain a digital ID, but the preferred way is to use Adobe software. These forms will be on file with MDOT until the individual’s digital signature certificate expires or until such time as the individual needs to create a new digital signature.<br />
<br />
{{top}}<br />
<br />
====[[#What is Digital Signature Validation and why does it matter?|What is digital Signature Validation and why does it matter?]]====<br />
<br />
All signatures must be authenticated to determine the identity of the document signer(s) and it is the legal requirement that anyone receiving a signature from an external party must authenticate the signature on the document they receive (paper or electronic). While handwritten signatures have visual indicators that help us determine someone’s real signature, the digital signature process is much faster and more secure. However, digital signatures can also be falsely created by other parties and made to look very similar to the authentic digital signatures, so care must be taken to determine the true identity of the signers. The process to determine the authenticity of digital signatures is referred to as signature validation.<br />
<br />
Validation is the process that authenticates the electronic signature on a document and compares it to the known validated signature on file.<br />
<br />
In general, the electronic signature validation process occurs primarily in the background of the software and only requires us to take action the first time a signature is received. A valid digital signature proves that the message was created by a known sender; such that the sender cannot deny having sent the message (authentication and non-repudiation) and that the message was not altered in transit (integrity). This is accomplished by the use of an algorithm that creates unique encrypted codes associated with the digital signature for the user. In general, each digital signature has two main components. The first is a private key code that is encrypted into the signature which is essentially the user’s password used to affix their signature. The second component is called the public key code which is a unique complex code embedded into the signature that allows other parties to easily authenticate the true identity of the signer. Each digital signatures public code is unique to the digital signature, not the person, thus if you have two digital signatures each has its own unique code, they are not the same. When a sender signs a document their private key remains with them, but the public key is embedded into the signature on the document. When the document is sent to the recipient, the recipient’s computer compares the unique public code in the signature to the list of known validated signature codes. If the codes match then the signature is considered valid and proves the signature was made by the sender. If the codes do not match, the software indicates the signature has not been validated. If this occurs the recipient is required to perform the validation process as described in the next section of this BOH IM. (Note the graphic process describing the validation process is presented in Attachment 1; e-Signature Validation Process Overview of this BOH IM.)<br />
<br />
Effective immediately, the process for validating Digital Electronic Signature (DES) received by MDOT from any external party will be as follows:<br />
<br />
:1. External Parties:<br />
<br />
::a. All external parties (non-MDOT/FHWA), intending to use DES on any documents to be submitted to MDOT, must submit form 5600 Statement of Digital Electronic Signature Validation to the local MDOT office for validation of the DES prior to (or concurrent with) the DES being used on any documents submitted to MDOT.<br />
<br />
::b. Form 5600 must be submitted for each individual DES the first time the signature is used on a project. This can be submitted concurrently with a document; however, the document will not be accepted until the validation process has been completed.<br />
<br />
::c. Most DES certificates expire after four (4) years from the initial date of the DES creation. It is the responsibility of the signature creator to maintain their DES and create a new DES when their current DES expires. Form 5600, once validated, will allow the use of the DES on other documents submitted to MDOT until the DES expires (including on other projects or in other offices).<br />
<br />
::d. If the DES owner changes employment, position, responsibilities, forgets the DES password, or loses the DES file, this will require that a new form 5600 be submitted for the new signature.<br />
<br />
:2. MDOT Office:<br />
<br />
Any document received by MDOT containing a DES must be checked for proper validation prior to acceptance. This can be confirmed via the blue signature panel validation process at the top of the document in Adobe Acrobat (Figure 1).<br />
<br />
Figure 1: Screen showing blue signature panel in Adobe Standard XI<br />
<br />
[[File:IM14-11Fig1.png|800px|thumb|center|Figure 1]]<br />
<br />
<br />
If the digital electronic signatures on the document have already been authenticated, the software will clearly confirm this with the green checkmark as shown below in Figure 2.<br />
<br />
[[File:IM14Fig2.png|400px|thumb|center|Figure 2]]<br />
<br />
<br />
If electronic documents come into the office with a non-validated DES, (figure 3 below), <br />
<br />
[[File:IM14Fig3.png|400px|thumb|center|Figure 3]]<br />
<br />
then the office must determine the validity of the document signers. If the signature does not match the previously validated signature codes on file the office must reject the document until a new form 5600 is submitted and the DES can be validated. '''It is the legal responsibility of the first person who receives any signature to verify the validity of the signature before accepting any documents.''' After the signature has been validated and added to the trusted list of validated signatures, the software will re-validate and display the green check mark. The completion of the form 5600 is only required when a signature is first used, subsequent documents will be validated automatically for that user. It may take a while for the central office database updates to be distributed to all other users, so until that occurs a signer can send along a copy of the fully completed form 5600 to the new office where they can manually add the validated signature to their trusted identities.<br />
<br />
In the case of multiple signatures on the same document, the software clearly identifies the signatures that have not been validated as shown in figure 4 below.<br />
<br />
<br />
[[File:IM14Fig4.png|400px|thumb|center|Figure 4]]<br />
<br />
<br />
The software also automatically tracks all changes made to the document. This is important because by the very act of signing a document, the document has changed from the version the first person saw. Any major changes to the document that affect the integrety of the encrypted digital signatures will invalidate or delete the signatures, but minor changes like multiple signers will just be noted.<br />
<br />
Should an office receive a document or form 5600 that requries them to validate the digital signature the process is simple and straightforeward.<br />
<br />
The validation process is detailed on form 5600 and the receiver must verify at least two (2) of the four (4) federal signature authentication requirements outlined below:<br />
<br />
::a. The name of the sender is the same name expected.<br />
::b. E-mail from a company domain e-mail address.<br />
::c. Direct contact with sender verifying they sent the document with signature.<br />
::d. Verification via another method with provided details.<br />
<br />
The MDOT recipient of the document is then required to indicate which two methods were used to verify the signature is actually from the recipient and then confirm their validation efforts by placing their own digital signature on the form. This form is then routed to the central office for archiving and a copy of the completed form returned to the sender for their records or for submission to other offices until the central database is updated.<br />
::a. MDOT office staff that receives form 5600 will go through and complete the validation steps per the form instructions.<br />
<br />
::b. Once the DES is validated, the validating MDOT office staff will countersign form 5600. <br />
<br />
::c. MDOT office staff will then add the validated signature to their trusted identities. Instructions for manually adding a validated signature to your trusted identities can be found on the MDOT WIKI Construction Manual in Division 1 Supplemental Information, e-Sign section. <br />
[[E-Signature|http://mdotwiki.state.mi.us/construction/index.php/E-Signature]]<br />
<br />
:d. MDOT office staff will then submit the completed form 5600 to <br />
[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov] and also back to the submitting applicant.<br />
<br />
:3. MDOT-Central Office:<br />
<br />
::a. MDOT Central Office staff will receive form 5600 via the <br />
[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov] e-mail address. MDOT Central Office staff will then maintain these 5600 forms in a centralized server for archiving purposes, update export files of all previously validated DES, and send these validated DES out to MDOT staff periodically.<br />
<br />
If you have any questions, contact[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov]. Please share this information with consultants and local agencies within your area.<br />
<br />
[[File:IM14-11Fig5.png|800px|thumb|center|Figure 5]]<br />
<br />
<br />
====[[#Resources|Resources]]====<br />
<br />
{| class="wikitable"<br />
|-<br />
! File Name !! Description <br />
|-<br />
| [//{{SERVERNAME}}/images_construction/f/fa/Setting_Up_an_Electronic_Signature.pdf Setting Up an Electronic Signature] || Creating a Digital Identity with Adobe Acrobat|| <br />
|-<br />
| [//{{SERVERNAME}}/images_construction/5/5d/How_To_Add_A_Digital_Signature_Via_iPhone_422065_7.pdf How To Add A Digital Signature Via iPhone] || Creating a Digital Signature on any iOS smart device<br />
|-<br />
| [//{{SERVERNAME}}/images_construction/a/a6/E-sign_brochure.pdf E-sign brochure] || A brief outline concering various facets of E-signatures<br />
|-<br />
|[http://www.youtube.com/watch?v=pUIWvJgkw8E How to Digitally Sign a document with Adobe Reader]||A YouTube video published by Adobe about how to digitally sign a PDF file with the free Adobe Reader<br />
|-<br />
|[http://www.michigan.gov/documents/mdot/Applying_an_Image_To_Digital_Signature_422061_7.pdf Applying an Image To Digital Signature]|| How to import and insert an image to a digital signature<br />
|-<br />
|[http://www.michigan.gov/documents/mdot/Trusting_and_Validating_a_Digital_Signature_422068_7.pdf Trusting and Validating a Digital Siganture]|| How to trust and validate a signature in Adobe Acrobat<br />
|-<br />
|}<br />
<br />
<br />
<br />
[[Category: Construction Manual]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=File:IM14-11Fig1.png&diff=3955File:IM14-11Fig1.png2015-03-05T13:54:34Z<p>HarrisR18: </p>
<hr />
<div></div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=E-Signature&diff=3954E-Signature2015-03-05T13:17:11Z<p>HarrisR18: </p>
<hr />
<div><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Division 1 Supplemental Information'''</span></center><br />
<center><span STYLE="font: 30pt arial;">'''e-Signature'''</span></center><br />
<br />
<br />
====[[#General Information|General Information]]====<br />
<br />
According to the Code of Federal Regulation, electronic signatures are defined as a computer data compilation of any symbol or series of symbols executed, adopted, or authorized by an individual to be the legally binding equivalent of the individual's handwritten signature. A specific type of electronic signature is digital signatures. Digital signatures are defined as an electronic signature based upon cryptographic methods of originator authentication, computed by using a set of rules and a set of parameters such that the identity of the signer and the integrity of the data can be verified. <br />
<br />
An entity such as a computer user can be assigned a unique digital identification. This digital identification is composed of a public key, a private key, and a digital certificate. As their names suggest, the public key should be shared amongst users who wish to carry out transactions amongst themselves, while the private key should be only known by its user. The digital certificate is used within a public-key infrastructure to allow a third-party certificate authority to verify that the digital certificate is correctly associated with that particular public key.<br />
<br />
As public keys are shared amongst a group of users, someone’s public key can be used to encrypt a document and their respective private key can be used to decrypt that document. Confidentiality and data integrity of the sent document can be practically guaranteed assuming if the recipient is the only one who knows their private key. Similarly, someone’s private key can be ‘embedded’ into a document to constitute an electronic signature, and the identity of the electronic signature may be verified by using that user’s public key. <br />
<br />
{{top}}<br />
<br />
====[[#Adoption at MDOT and Acceptable Uses|Adoption at MDOT and Acceptable Uses]]====<br />
The Michigan Attorney General’s office, in concurrence of the Federal Highway Administration, has issued a decision authorizing the Michigan Department of Transportation (MDOT) to use and accept digital signatures (see [http://www.michigan.gov/documents/mdot/MDOT_IM12-02_378056_7.pdf BOH IM 2012-02]).<br />
<br />
There are many standards available for digital signatures, but MDOT currently authorizes the use of PKCS#12 files for digital identification. This cryptographic standard requires the signer to enter their unique password each time they digitally sign a document. To digitally sign a document, you must first have a digital identification (ID). This ID can be obtained from various certification authorities, but MDOT will primarily use Adobe as a certification authority. [http://www.michigan.gov/documents/mdot/Setting_Up_an_Electronic_Signature_422066_7.pdf This PDF file] and [http://www.youtube.com/watch?v=pUIWvJgkw8E this YouTube video, produced by Adobe Acrobat,] shows how to create a digital ID on Adobe Reader.<br />
<br />
Digital signatures created with Adobe Software need to conform to the following style guidelines: <br />
*Graphic options shall be:<br />
**“Name” Or “Imported Graphic” (as outlined below)<br />
<br />
*Configure text shall be configured as:<br />
**Uncheck the adobe “logo”<br />
**Required to include: (“Name”, “Date”, “Location” and “Reason”)<br />
**Optional “Distinguished Name” (includes job title)<br />
**Optional for “labels”<br />
**“left to right”<br />
You may have multiple digital signature files configured for different purposes. It is even possible to configure a digital signature with an “Imported Graphic” (refer to this [http://www.michigan.gov/documents/mdot/Applying_an_Image_To_Digital_Signature_422061_7.pdf PDF]) containing an image of your scanned written signature or a scan of a professional license stamp. These are acceptable, but written signature images are not required and non-business related graphics are not acceptable.<br />
<br />
Similar to how handwritten signatures must be verified, it is the responsibility of the recipient of a electronically signed document to confirm the identity of the signer/sender before the electronic signature may be considered valid. The recipient should consider whether or not that the document was sent from a recognized e-mail account and that the expected signer has been previously validated. If you are unsure, then you can verify by contacting their place of business. Adobe Acrobat software has an integrated validation feature that stores validated signatures, meaning that the user does not need to validate those signatures again. This [http://www.michigan.gov/documents/mdot/Trusting_and_Validating_a_Digital_Signature_422068_7.pdf PDF] shows how to validate a signature.<br />
<br />
MDOT is working on integration of electronic signatures on mobile devices. There are several mobile applications that allow PDF files to be digitally signed using mobile devices, but as of now none have been authorized for employee use. Employees are encouraged to submit mobile applications to the E-Sign team of the Construction Field Services Division and to the Department of Technology, Management and Budget. This [http://www.michigan.gov/documents/mdot/How_To_Add_A_Digital_Signature_Via_iPhone_422065_7.pdf PDF] shows how to digitally sign a PDF file on an iPhone.<br />
<br />
It is important to note that for records retention and archiving purposes whenever digital signatures are used on documents, the electronic file (usually PDF) is considered the original legal document. Printouts of the document containing digital signatures are considered copies, so the signed electronic file must be retained and follow the relevant approved records retention procedures. MDOT will address the records storage issue through the requirement that all electronically signed documents must be placed in the project directory in the ProjectWise document management program. The E-construction [http://mdotwiki.state.mi.us/construction/index.php/E-Construction wiki page] contains more information regarding ProjectWise. <br />
{{top}}<br />
<br />
====[[#Guidance for Non-MDOT Users|Guidance for Non-MDOT Users]]====<br />
<br />
An individual’s digital signature must be validated before MDOT can accept the signature. [http://mdotcf.state.mi.us/public/webforms/public/5600.pdf Form 5600] for contractors and [http://mdotcf.state.mi.us/public/webforms/public/5600A.pdf Form 5600A] for consultants allows an individual to submit their digital signature to MDOT. When you select the signature box when filling out these forms, you can use an existing digital ID or you can create a new ID. There are many ways an individual can obtain a digital ID, but the preferred way is to use Adobe software. These forms will be on file with MDOT until the individual’s digital signature certificate expires or until such time as the individual needs to create a new digital signature.<br />
<br />
{{top}}<br />
<br />
====[[#What is Digital Signature Validation and why does it matter?|What is digital Signature Validation and why does it matter?]]====<br />
<br />
All signatures must be authenticated to determine the identity of the document signer(s) and it is the legal requirement that anyone receiving a signature from an external party must authenticate the signature on the document they receive (paper or electronic). While handwritten signatures have visual indicators that help us determine someone’s real signature, the digital signature process is much faster and more secure. However, digital signatures can also be falsely created by other parties and made to look very similar to the authentic digital signatures, so care must be taken to determine the true identity of the signers. The process to determine the authenticity of digital signatures is referred to as signature validation.<br />
<br />
Validation is the process that authenticates the electronic signature on a document and compares it to the known validated signature on file.<br />
<br />
In general, the electronic signature validation process occurs primarily in the background of the software and only requires us to take action the first time a signature is received. A valid digital signature proves that the message was created by a known sender; such that the sender cannot deny having sent the message (authentication and non-repudiation) and that the message was not altered in transit (integrity). This is accomplished by the use of an algorithm that creates unique encrypted codes associated with the digital signature for the user. In general, each digital signature has two main components. The first is a private key code that is encrypted into the signature which is essentially the user’s password used to affix their signature. The second component is called the public key code which is a unique complex code embedded into the signature that allows other parties to easily authenticate the true identity of the signer. Each digital signatures public code is unique to the digital signature, not the person, thus if you have two digital signatures each has its own unique code, they are not the same. When a sender signs a document their private key remains with them, but the public key is embedded into the signature on the document. When the document is sent to the recipient, the recipient’s computer compares the unique public code in the signature to the list of known validated signature codes. If the codes match then the signature is considered valid and proves the signature was made by the sender. If the codes do not match, the software indicates the signature has not been validated. If this occurs the recipient is required to perform the validation process as described in the next section of this BOH IM. (Note the graphic process describing the validation process is presented in Attachment 1; e-Signature Validation Process Overview of this BOH IM.)<br />
<br />
Effective immediately, the process for validating Digital Electronic Signature (DES) received by MDOT from any external party will be as follows:<br />
<br />
:1. External Parties:<br />
<br />
::a. All external parties (non-MDOT/FHWA), intending to use DES on any documents to be submitted to MDOT, must submit form 5600 Statement of Digital Electronic Signature Validation to the local MDOT office for validation of the DES prior to (or concurrent with) the DES being used on any documents submitted to MDOT.<br />
<br />
::b. Form 5600 must be submitted for each individual DES the first time the signature is used on a project. This can be submitted concurrently with a document; however, the document will not be accepted until the validation process has been completed.<br />
<br />
::c. Most DES certificates expire after four (4) years from the initial date of the DES creation. It is the responsibility of the signature creator to maintain their DES and create a new DES when their current DES expires. Form 5600, once validated, will allow the use of the DES on other documents submitted to MDOT until the DES expires (including on other projects or in other offices).<br />
<br />
::d. If the DES owner changes employment, position, responsibilities, forgets the DES password, or loses the DES file, this will require that a new form 5600 be submitted for the new signature.<br />
<br />
:2. MDOT Office:<br />
<br />
Any document received by MDOT containing a DES must be checked for proper validation prior to acceptance. This can be confirmed via the blue signature panel validation process at the top of the document in Adobe Acrobat (Figure 1).<br />
<br />
Figure 1: Screen showing blue signature panel in Adobe Standard XI<br />
<br />
[[File:IM14Fig1.png|1000px|thumb|center|Figure 1]]<br />
<br />
<br />
If the digital electronic signatures on the document have already been authenticated, the software will clearly confirm this with the green checkmark as shown below in Figure 2.<br />
<br />
[[File:IM14Fig2.png|400px|thumb|center|Figure 2]]<br />
<br />
<br />
If electronic documents come into the office with a non-validated DES, (figure 3 below), <br />
<br />
[[File:IM14Fig3.png|400px|thumb|center|Figure 3]]<br />
<br />
then the office must determine the validity of the document signers. If the signature does not match the previously validated signature codes on file the office must reject the document until a new form 5600 is submitted and the DES can be validated. '''It is the legal responsibility of the first person who receives any signature to verify the validity of the signature before accepting any documents.''' After the signature has been validated and added to the trusted list of validated signatures, the software will re-validate and display the green check mark. The completion of the form 5600 is only required when a signature is first used, subsequent documents will be validated automatically for that user. It may take a while for the central office database updates to be distributed to all other users, so until that occurs a signer can send along a copy of the fully completed form 5600 to the new office where they can manually add the validated signature to their trusted identities.<br />
<br />
In the case of multiple signatures on the same document, the software clearly identifies the signatures that have not been validated as shown in figure 4 below.<br />
<br />
<br />
[[File:IM14Fig4.png|400px|thumb|center|Figure 4]]<br />
<br />
<br />
The software also automatically tracks all changes made to the document. This is important because by the very act of signing a document, the document has changed from the version the first person saw. Any major changes to the document that affect the integrety of the encrypted digital signatures will invalidate or delete the signatures, but minor changes like multiple signers will just be noted.<br />
<br />
Should an office receive a document or form 5600 that requries them to validate the digital signature the process is simple and straightforeward.<br />
<br />
The validation process is detailed on form 5600 and the receiver must verify at least two (2) of the four (4) federal signature authentication requirements outlined below:<br />
<br />
::a. The name of the sender is the same name expected.<br />
::b. E-mail from a company domain e-mail address.<br />
::c. Direct contact with sender verifying they sent the document with signature.<br />
::d. Verification via another method with provided details.<br />
<br />
The MDOT recipient of the document is then required to indicate which two methods were used to verify the signature is actually from the recipient and then confirm their validation efforts by placing their own digital signature on the form. This form is then routed to the central office for archiving and a copy of the completed form returned to the sender for their records or for submission to other offices until the central database is updated.<br />
::a. MDOT office staff that receives form 5600 will go through and complete the validation steps per the form instructions.<br />
<br />
::b. Once the DES is validated, the validating MDOT office staff will countersign form 5600. <br />
<br />
::c. MDOT office staff will then add the validated signature to their trusted identities. Instructions for manually adding a validated signature to your trusted identities can be found on the MDOT WIKI Construction Manual in Division 1 Supplemental Information, e-Sign section. <br />
[[E-Signature|http://mdotwiki.state.mi.us/construction/index.php/E-Signature]]<br />
<br />
:d. MDOT office staff will then submit the completed form 5600 to <br />
[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov] and also back to the submitting applicant.<br />
<br />
:3. MDOT-Central Office:<br />
<br />
::a. MDOT Central Office staff will receive form 5600 via the <br />
[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov] e-mail address. MDOT Central Office staff will then maintain these 5600 forms in a centralized server for archiving purposes, update export files of all previously validated DES, and send these validated DES out to MDOT staff periodically.<br />
<br />
If you have any questions, contact[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov]. Please share this information with consultants and local agencies within your area.<br />
<br />
[[File:IM14-11Fig5.png|800px|thumb|center|Figure 5]]<br />
<br />
<br />
====[[#Resources|Resources]]====<br />
<br />
{| class="wikitable"<br />
|-<br />
! File Name !! Description <br />
|-<br />
| [//{{SERVERNAME}}/images_construction/f/fa/Setting_Up_an_Electronic_Signature.pdf Setting Up an Electronic Signature] || Creating a Digital Identity with Adobe Acrobat|| <br />
|-<br />
| [//{{SERVERNAME}}/images_construction/5/5d/How_To_Add_A_Digital_Signature_Via_iPhone_422065_7.pdf How To Add A Digital Signature Via iPhone] || Creating a Digital Signature on any iOS smart device<br />
|-<br />
| [//{{SERVERNAME}}/images_construction/a/a6/E-sign_brochure.pdf E-sign brochure] || A brief outline concering various facets of E-signatures<br />
|-<br />
|[http://www.youtube.com/watch?v=pUIWvJgkw8E How to Digitally Sign a document with Adobe Reader]||A YouTube video published by Adobe about how to digitally sign a PDF file with the free Adobe Reader<br />
|-<br />
|[http://www.michigan.gov/documents/mdot/Applying_an_Image_To_Digital_Signature_422061_7.pdf Applying an Image To Digital Signature]|| How to import and insert an image to a digital signature<br />
|-<br />
|[http://www.michigan.gov/documents/mdot/Trusting_and_Validating_a_Digital_Signature_422068_7.pdf Trusting and Validating a Digital Siganture]|| How to trust and validate a signature in Adobe Acrobat<br />
|-<br />
|}<br />
<br />
<br />
<br />
[[Category: Construction Manual]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=File:IM14-11Fig5.png&diff=3953File:IM14-11Fig5.png2015-03-05T13:12:23Z<p>HarrisR18: </p>
<hr />
<div></div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=E-Signature&diff=3952E-Signature2015-03-05T13:07:20Z<p>HarrisR18: </p>
<hr />
<div><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Division 1 Supplemental Information'''</span></center><br />
<center><span STYLE="font: 30pt arial;">'''e-Signature'''</span></center><br />
<br />
<br />
====[[#General Information|General Information]]====<br />
<br />
According to the Code of Federal Regulation, electronic signatures are defined as a computer data compilation of any symbol or series of symbols executed, adopted, or authorized by an individual to be the legally binding equivalent of the individual's handwritten signature. A specific type of electronic signature is digital signatures. Digital signatures are defined as an electronic signature based upon cryptographic methods of originator authentication, computed by using a set of rules and a set of parameters such that the identity of the signer and the integrity of the data can be verified. <br />
<br />
An entity such as a computer user can be assigned a unique digital identification. This digital identification is composed of a public key, a private key, and a digital certificate. As their names suggest, the public key should be shared amongst users who wish to carry out transactions amongst themselves, while the private key should be only known by its user. The digital certificate is used within a public-key infrastructure to allow a third-party certificate authority to verify that the digital certificate is correctly associated with that particular public key.<br />
<br />
As public keys are shared amongst a group of users, someone’s public key can be used to encrypt a document and their respective private key can be used to decrypt that document. Confidentiality and data integrity of the sent document can be practically guaranteed assuming if the recipient is the only one who knows their private key. Similarly, someone’s private key can be ‘embedded’ into a document to constitute an electronic signature, and the identity of the electronic signature may be verified by using that user’s public key. <br />
<br />
{{top}}<br />
<br />
====[[#Adoption at MDOT and Acceptable Uses|Adoption at MDOT and Acceptable Uses]]====<br />
The Michigan Attorney General’s office, in concurrence of the Federal Highway Administration, has issued a decision authorizing the Michigan Department of Transportation (MDOT) to use and accept digital signatures (see [http://www.michigan.gov/documents/mdot/MDOT_IM12-02_378056_7.pdf BOH IM 2012-02]).<br />
<br />
There are many standards available for digital signatures, but MDOT currently authorizes the use of PKCS#12 files for digital identification. This cryptographic standard requires the signer to enter their unique password each time they digitally sign a document. To digitally sign a document, you must first have a digital identification (ID). This ID can be obtained from various certification authorities, but MDOT will primarily use Adobe as a certification authority. [http://www.michigan.gov/documents/mdot/Setting_Up_an_Electronic_Signature_422066_7.pdf This PDF file] and [http://www.youtube.com/watch?v=pUIWvJgkw8E this YouTube video, produced by Adobe Acrobat,] shows how to create a digital ID on Adobe Reader.<br />
<br />
Digital signatures created with Adobe Software need to conform to the following style guidelines: <br />
*Graphic options shall be:<br />
**“Name” Or “Imported Graphic” (as outlined below)<br />
<br />
*Configure text shall be configured as:<br />
**Uncheck the adobe “logo”<br />
**Required to include: (“Name”, “Date”, “Location” and “Reason”)<br />
**Optional “Distinguished Name” (includes job title)<br />
**Optional for “labels”<br />
**“left to right”<br />
You may have multiple digital signature files configured for different purposes. It is even possible to configure a digital signature with an “Imported Graphic” (refer to this [http://www.michigan.gov/documents/mdot/Applying_an_Image_To_Digital_Signature_422061_7.pdf PDF]) containing an image of your scanned written signature or a scan of a professional license stamp. These are acceptable, but written signature images are not required and non-business related graphics are not acceptable.<br />
<br />
Similar to how handwritten signatures must be verified, it is the responsibility of the recipient of a electronically signed document to confirm the identity of the signer/sender before the electronic signature may be considered valid. The recipient should consider whether or not that the document was sent from a recognized e-mail account and that the expected signer has been previously validated. If you are unsure, then you can verify by contacting their place of business. Adobe Acrobat software has an integrated validation feature that stores validated signatures, meaning that the user does not need to validate those signatures again. This [http://www.michigan.gov/documents/mdot/Trusting_and_Validating_a_Digital_Signature_422068_7.pdf PDF] shows how to validate a signature.<br />
<br />
MDOT is working on integration of electronic signatures on mobile devices. There are several mobile applications that allow PDF files to be digitally signed using mobile devices, but as of now none have been authorized for employee use. Employees are encouraged to submit mobile applications to the E-Sign team of the Construction Field Services Division and to the Department of Technology, Management and Budget. This [http://www.michigan.gov/documents/mdot/How_To_Add_A_Digital_Signature_Via_iPhone_422065_7.pdf PDF] shows how to digitally sign a PDF file on an iPhone.<br />
<br />
It is important to note that for records retention and archiving purposes whenever digital signatures are used on documents, the electronic file (usually PDF) is considered the original legal document. Printouts of the document containing digital signatures are considered copies, so the signed electronic file must be retained and follow the relevant approved records retention procedures. MDOT will address the records storage issue through the requirement that all electronically signed documents must be placed in the project directory in the ProjectWise document management program. The E-construction [http://mdotwiki.state.mi.us/construction/index.php/E-Construction wiki page] contains more information regarding ProjectWise. <br />
{{top}}<br />
<br />
====[[#Guidance for Non-MDOT Users|Guidance for Non-MDOT Users]]====<br />
<br />
An individual’s digital signature must be validated before MDOT can accept the signature. [http://mdotcf.state.mi.us/public/webforms/public/5600.pdf Form 5600] for contractors and [http://mdotcf.state.mi.us/public/webforms/public/5600A.pdf Form 5600A] for consultants allows an individual to submit their digital signature to MDOT. When you select the signature box when filling out these forms, you can use an existing digital ID or you can create a new ID. There are many ways an individual can obtain a digital ID, but the preferred way is to use Adobe software. These forms will be on file with MDOT until the individual’s digital signature certificate expires or until such time as the individual needs to create a new digital signature.<br />
<br />
{{top}}<br />
<br />
====[[#What is Digital Signature Validation and why does it matter?|What is digital Signature Validation and why does it matter?]]====<br />
<br />
All signatures must be authenticated to determine the identity of the document signer(s) and it is the legal requirement that anyone receiving a signature from an external party must authenticate the signature on the document they receive (paper or electronic). While handwritten signatures have visual indicators that help us determine someone’s real signature, the digital signature process is much faster and more secure. However, digital signatures can also be falsely created by other parties and made to look very similar to the authentic digital signatures, so care must be taken to determine the true identity of the signers. The process to determine the authenticity of digital signatures is referred to as signature validation.<br />
<br />
Validation is the process that authenticates the electronic signature on a document and compares it to the known validated signature on file.<br />
<br />
In general, the electronic signature validation process occurs primarily in the background of the software and only requires us to take action the first time a signature is received. A valid digital signature proves that the message was created by a known sender; such that the sender cannot deny having sent the message (authentication and non-repudiation) and that the message was not altered in transit (integrity). This is accomplished by the use of an algorithm that creates unique encrypted codes associated with the digital signature for the user. In general, each digital signature has two main components. The first is a private key code that is encrypted into the signature which is essentially the user’s password used to affix their signature. The second component is called the public key code which is a unique complex code embedded into the signature that allows other parties to easily authenticate the true identity of the signer. Each digital signatures public code is unique to the digital signature, not the person, thus if you have two digital signatures each has its own unique code, they are not the same. When a sender signs a document their private key remains with them, but the public key is embedded into the signature on the document. When the document is sent to the recipient, the recipient’s computer compares the unique public code in the signature to the list of known validated signature codes. If the codes match then the signature is considered valid and proves the signature was made by the sender. If the codes do not match, the software indicates the signature has not been validated. If this occurs the recipient is required to perform the validation process as described in the next section of this BOH IM. (Note the graphic process describing the validation process is presented in Attachment 1; e-Signature Validation Process Overview of this BOH IM.)<br />
<br />
Effective immediately, the process for validating Digital Electronic Signature (DES) received by MDOT from any external party will be as follows:<br />
<br />
:1. External Parties:<br />
<br />
::a. All external parties (non-MDOT/FHWA), intending to use DES on any documents to be submitted to MDOT, must submit form 5600 Statement of Digital Electronic Signature Validation to the local MDOT office for validation of the DES prior to (or concurrent with) the DES being used on any documents submitted to MDOT.<br />
<br />
::b. Form 5600 must be submitted for each individual DES the first time the signature is used on a project. This can be submitted concurrently with a document; however, the document will not be accepted until the validation process has been completed.<br />
<br />
::c. Most DES certificates expire after four (4) years from the initial date of the DES creation. It is the responsibility of the signature creator to maintain their DES and create a new DES when their current DES expires. Form 5600, once validated, will allow the use of the DES on other documents submitted to MDOT until the DES expires (including on other projects or in other offices).<br />
<br />
::d. If the DES owner changes employment, position, responsibilities, forgets the DES password, or loses the DES file, this will require that a new form 5600 be submitted for the new signature.<br />
<br />
:2. MDOT Office:<br />
<br />
Any document received by MDOT containing a DES must be checked for proper validation prior to acceptance. This can be confirmed via the blue signature panel validation process at the top of the document in Adobe Acrobat (Figure 1).<br />
<br />
Figure 1: Screen showing blue signature panel in Adobe Standard XI<br />
<br />
[[File:IM14Fig1.png|200px|thumb|center|alt text]]<br />
<br />
<br />
If the digital electronic signatures on the document have already been authenticated, the software will clearly confirm this with the green checkmark as shown below in Figure 2.<br />
<br />
[[File:IM14Fig2.png|200px|thumb|center|alt text]]<br />
<br />
<br />
If electronic documents come into the office with a non-validated DES, (figure 3 below), <br />
<br />
[[File:IM14Fig3.png|200px|thumb|center|alt text]]<br />
<br />
then the office must determine the validity of the document signers. If the signature does not match the previously validated signature codes on file the office must reject the document until a new form 5600 is submitted and the DES can be validated. '''It is the legal responsibility of the first person who receives any signature to verify the validity of the signature before accepting any documents.''' After the signature has been validated and added to the trusted list of validated signatures, the software will re-validate and display the green check mark. The completion of the form 5600 is only required when a signature is first used, subsequent documents will be validated automatically for that user. It may take a while for the central office database updates to be distributed to all other users, so until that occurs a signer can send along a copy of the fully completed form 5600 to the new office where they can manually add the validated signature to their trusted identities.<br />
<br />
In the case of multiple signatures on the same document, the software clearly identifies the signatures that have not been validated as shown in figure 4 below.<br />
<br />
<br />
[[File:IM14Fig4.png|200px|thumb|center|alt text]]<br />
<br />
<br />
The software also automatically tracks all changes made to the document. This is important because by the very act of signing a document, the document has changed from the version the first person saw. Any major changes to the document that affect the integrety of the encrypted digital signatures will invalidate or delete the signatures, but minor changes like multiple signers will just be noted.<br />
<br />
Should an office receive a document or form 5600 that requries them to validate the digital signature the process is simple and straightforeward.<br />
<br />
The validation process is detailed on form 5600 and the receiver must verify at least two (2) of the four (4) federal signature authentication requirements outlined below:<br />
<br />
::a. The name of the sender is the same name expected.<br />
::b. E-mail from a company domain e-mail address.<br />
::c. Direct contact with sender verifying they sent the document with signature.<br />
::d. Verification via another method with provided details.<br />
<br />
The MDOT recipient of the document is then required to indicate which two methods were used to verify the signature is actually from the recipient and then confirm their validation efforts by placing their own digital signature on the form. This form is then routed to the central office for archiving and a copy of the completed form returned to the sender for their records or for submission to other offices until the central database is updated.<br />
::a. MDOT office staff that receives form 5600 will go through and complete the validation steps per the form instructions.<br />
<br />
::b. Once the DES is validated, the validating MDOT office staff will countersign form 5600. <br />
<br />
::c. MDOT office staff will then add the validated signature to their trusted identities. Instructions for manually adding a validated signature to your trusted identities can be found on the MDOT WIKI Construction Manual in Division 1 Supplemental Information, e-Sign section. <br />
[[E-Signature|http://mdotwiki.state.mi.us/construction/index.php/E-Signature]]<br />
<br />
:d. MDOT office staff will then submit the completed form 5600 to <br />
[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov] and also back to the submitting applicant.<br />
<br />
:3. MDOT-Central Office:<br />
<br />
::a. MDOT Central Office staff will receive form 5600 via the <br />
[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov] e-mail address. MDOT Central Office staff will then maintain these 5600 forms in a centralized server for archiving purposes, update export files of all previously validated DES, and send these validated DES out to MDOT staff periodically.<br />
<br />
If you have any questions, contact[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov]. Please share this information with consultants and local agencies within your area.<br />
<br />
====[[#Resources|Resources]]====<br />
<br />
{| class="wikitable"<br />
|-<br />
! File Name !! Description <br />
|-<br />
| [//{{SERVERNAME}}/images_construction/f/fa/Setting_Up_an_Electronic_Signature.pdf Setting Up an Electronic Signature] || Creating a Digital Identity with Adobe Acrobat|| <br />
|-<br />
| [//{{SERVERNAME}}/images_construction/5/5d/How_To_Add_A_Digital_Signature_Via_iPhone_422065_7.pdf How To Add A Digital Signature Via iPhone] || Creating a Digital Signature on any iOS smart device<br />
|-<br />
| [//{{SERVERNAME}}/images_construction/a/a6/E-sign_brochure.pdf E-sign brochure] || A brief outline concering various facets of E-signatures<br />
|-<br />
|[http://www.youtube.com/watch?v=pUIWvJgkw8E How to Digitally Sign a document with Adobe Reader]||A YouTube video published by Adobe about how to digitally sign a PDF file with the free Adobe Reader<br />
|-<br />
|[http://www.michigan.gov/documents/mdot/Applying_an_Image_To_Digital_Signature_422061_7.pdf Applying an Image To Digital Signature]|| How to import and insert an image to a digital signature<br />
|-<br />
|[http://www.michigan.gov/documents/mdot/Trusting_and_Validating_a_Digital_Signature_422068_7.pdf Trusting and Validating a Digital Siganture]|| How to trust and validate a signature in Adobe Acrobat<br />
|-<br />
|}<br />
<br />
<br />
<br />
[[Category: Construction Manual]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=E-Signature&diff=3951E-Signature2015-03-05T13:04:41Z<p>HarrisR18: </p>
<hr />
<div><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Division 1 Supplemental Information'''</span></center><br />
<center><span STYLE="font: 30pt arial;">'''e-Signature'''</span></center><br />
<br />
<br />
====[[#General Information|General Information]]====<br />
<br />
According to the Code of Federal Regulation, electronic signatures are defined as a computer data compilation of any symbol or series of symbols executed, adopted, or authorized by an individual to be the legally binding equivalent of the individual's handwritten signature. A specific type of electronic signature is digital signatures. Digital signatures are defined as an electronic signature based upon cryptographic methods of originator authentication, computed by using a set of rules and a set of parameters such that the identity of the signer and the integrity of the data can be verified. <br />
<br />
An entity such as a computer user can be assigned a unique digital identification. This digital identification is composed of a public key, a private key, and a digital certificate. As their names suggest, the public key should be shared amongst users who wish to carry out transactions amongst themselves, while the private key should be only known by its user. The digital certificate is used within a public-key infrastructure to allow a third-party certificate authority to verify that the digital certificate is correctly associated with that particular public key.<br />
<br />
As public keys are shared amongst a group of users, someone’s public key can be used to encrypt a document and their respective private key can be used to decrypt that document. Confidentiality and data integrity of the sent document can be practically guaranteed assuming if the recipient is the only one who knows their private key. Similarly, someone’s private key can be ‘embedded’ into a document to constitute an electronic signature, and the identity of the electronic signature may be verified by using that user’s public key. <br />
<br />
{{top}}<br />
<br />
====[[#Adoption at MDOT and Acceptable Uses|Adoption at MDOT and Acceptable Uses]]====<br />
The Michigan Attorney General’s office, in concurrence of the Federal Highway Administration, has issued a decision authorizing the Michigan Department of Transportation (MDOT) to use and accept digital signatures (see [http://www.michigan.gov/documents/mdot/MDOT_IM12-02_378056_7.pdf BOH IM 2012-02]).<br />
<br />
There are many standards available for digital signatures, but MDOT currently authorizes the use of PKCS#12 files for digital identification. This cryptographic standard requires the signer to enter their unique password each time they digitally sign a document. To digitally sign a document, you must first have a digital identification (ID). This ID can be obtained from various certification authorities, but MDOT will primarily use Adobe as a certification authority. [http://www.michigan.gov/documents/mdot/Setting_Up_an_Electronic_Signature_422066_7.pdf This PDF file] and [http://www.youtube.com/watch?v=pUIWvJgkw8E this YouTube video, produced by Adobe Acrobat,] shows how to create a digital ID on Adobe Reader.<br />
<br />
Digital signatures created with Adobe Software need to conform to the following style guidelines: <br />
*Graphic options shall be:<br />
**“Name” Or “Imported Graphic” (as outlined below)<br />
<br />
*Configure text shall be configured as:<br />
**Uncheck the adobe “logo”<br />
**Required to include: (“Name”, “Date”, “Location” and “Reason”)<br />
**Optional “Distinguished Name” (includes job title)<br />
**Optional for “labels”<br />
**“left to right”<br />
You may have multiple digital signature files configured for different purposes. It is even possible to configure a digital signature with an “Imported Graphic” (refer to this [http://www.michigan.gov/documents/mdot/Applying_an_Image_To_Digital_Signature_422061_7.pdf PDF]) containing an image of your scanned written signature or a scan of a professional license stamp. These are acceptable, but written signature images are not required and non-business related graphics are not acceptable.<br />
<br />
Similar to how handwritten signatures must be verified, it is the responsibility of the recipient of a electronically signed document to confirm the identity of the signer/sender before the electronic signature may be considered valid. The recipient should consider whether or not that the document was sent from a recognized e-mail account and that the expected signer has been previously validated. If you are unsure, then you can verify by contacting their place of business. Adobe Acrobat software has an integrated validation feature that stores validated signatures, meaning that the user does not need to validate those signatures again. This [http://www.michigan.gov/documents/mdot/Trusting_and_Validating_a_Digital_Signature_422068_7.pdf PDF] shows how to validate a signature.<br />
<br />
MDOT is working on integration of electronic signatures on mobile devices. There are several mobile applications that allow PDF files to be digitally signed using mobile devices, but as of now none have been authorized for employee use. Employees are encouraged to submit mobile applications to the E-Sign team of the Construction Field Services Division and to the Department of Technology, Management and Budget. This [http://www.michigan.gov/documents/mdot/How_To_Add_A_Digital_Signature_Via_iPhone_422065_7.pdf PDF] shows how to digitally sign a PDF file on an iPhone.<br />
<br />
It is important to note that for records retention and archiving purposes whenever digital signatures are used on documents, the electronic file (usually PDF) is considered the original legal document. Printouts of the document containing digital signatures are considered copies, so the signed electronic file must be retained and follow the relevant approved records retention procedures. MDOT will address the records storage issue through the requirement that all electronically signed documents must be placed in the project directory in the ProjectWise document management program. The E-construction [http://mdotwiki.state.mi.us/construction/index.php/E-Construction wiki page] contains more information regarding ProjectWise. <br />
{{top}}<br />
<br />
====[[#Guidance for Non-MDOT Users|Guidance for Non-MDOT Users]]====<br />
<br />
An individual’s digital signature must be validated before MDOT can accept the signature. [http://mdotcf.state.mi.us/public/webforms/public/5600.pdf Form 5600] for contractors and [http://mdotcf.state.mi.us/public/webforms/public/5600A.pdf Form 5600A] for consultants allows an individual to submit their digital signature to MDOT. When you select the signature box when filling out these forms, you can use an existing digital ID or you can create a new ID. There are many ways an individual can obtain a digital ID, but the preferred way is to use Adobe software. These forms will be on file with MDOT until the individual’s digital signature certificate expires or until such time as the individual needs to create a new digital signature.<br />
<br />
====[[#What is Digital Signature Validation and why does it matter?|What is digital Signature Validation and why does it matter?]]====<br />
<br />
All signatures must be authenticated to determine the identity of the document signer(s) and it is the legal requirement that anyone receiving a signature from an external party must authenticate the signature on the document they receive (paper or electronic). While handwritten signatures have visual indicators that help us determine someone’s real signature, the digital signature process is much faster and more secure. However, digital signatures can also be falsely created by other parties and made to look very similar to the authentic digital signatures, so care must be taken to determine the true identity of the signers. The process to determine the authenticity of digital signatures is referred to as signature validation.<br />
<br />
Validation is the process that authenticates the electronic signature on a document and compares it to the known validated signature on file.<br />
<br />
In general, the electronic signature validation process occurs primarily in the background of the software and only requires us to take action the first time a signature is received. A valid digital signature proves that the message was created by a known sender; such that the sender cannot deny having sent the message (authentication and non-repudiation) and that the message was not altered in transit (integrity). This is accomplished by the use of an algorithm that creates unique encrypted codes associated with the digital signature for the user. In general, each digital signature has two main components. The first is a private key code that is encrypted into the signature which is essentially the user’s password used to affix their signature. The second component is called the public key code which is a unique complex code embedded into the signature that allows other parties to easily authenticate the true identity of the signer. Each digital signatures public code is unique to the digital signature, not the person, thus if you have two digital signatures each has its own unique code, they are not the same. When a sender signs a document their private key remains with them, but the public key is embedded into the signature on the document. When the document is sent to the recipient, the recipient’s computer compares the unique public code in the signature to the list of known validated signature codes. If the codes match then the signature is considered valid and proves the signature was made by the sender. If the codes do not match, the software indicates the signature has not been validated. If this occurs the recipient is required to perform the validation process as described in the next section of this BOH IM. (Note the graphic process describing the validation process is presented in Attachment 1; e-Signature Validation Process Overview of this BOH IM.)<br />
<br />
Effective immediately, the process for validating Digital Electronic Signature (DES) received by MDOT from any external party will be as follows:<br />
<br />
:1. External Parties:<br />
<br />
::a. All external parties (non-MDOT/FHWA), intending to use DES on any documents to be submitted to MDOT, must submit form 5600 Statement of Digital Electronic Signature Validation to the local MDOT office for validation of the DES prior to (or concurrent with) the DES being used on any documents submitted to MDOT.<br />
<br />
::b. Form 5600 must be submitted for each individual DES the first time the signature is used on a project. This can be submitted concurrently with a document; however, the document will not be accepted until the validation process has been completed.<br />
<br />
::c. Most DES certificates expire after four (4) years from the initial date of the DES creation. It is the responsibility of the signature creator to maintain their DES and create a new DES when their current DES expires. Form 5600, once validated, will allow the use of the DES on other documents submitted to MDOT until the DES expires (including on other projects or in other offices).<br />
<br />
::d. If the DES owner changes employment, position, responsibilities, forgets the DES password, or loses the DES file, this will require that a new form 5600 be submitted for the new signature.<br />
<br />
:2. MDOT Office:<br />
<br />
Any document received by MDOT containing a DES must be checked for proper validation prior to acceptance. This can be confirmed via the blue signature panel validation process at the top of the document in Adobe Acrobat (Figure 1).<br />
<br />
Figure 1: Screen showing blue signature panel in Adobe Standard XI<br />
<br />
[[File:IM14Fig1.png|200px|thumb|center|alt text]]<br />
<br />
<br />
If the digital electronic signatures on the document have already been authenticated, the software will clearly confirm this with the green checkmark as shown below in Figure 2.<br />
<br />
[[File:IM14Fig2.png|200px|thumb|center|alt text]]<br />
<br />
<br />
If electronic documents come into the office with a non-validated DES, (figure 3 below), <br />
<br />
[[File:IM14Fig3.png|200px|thumb|center|alt text]]<br />
<br />
then the office must determine the validity of the document signers. If the signature does not match the previously validated signature codes on file the office must reject the document until a new form 5600 is submitted and the DES can be validated. '''It is the legal responsibility of the first person who receives any signature to verify the validity of the signature before accepting any documents.''' After the signature has been validated and added to the trusted list of validated signatures, the software will re-validate and display the green check mark. The completion of the form 5600 is only required when a signature is first used, subsequent documents will be validated automatically for that user. It may take a while for the central office database updates to be distributed to all other users, so until that occurs a signer can send along a copy of the fully completed form 5600 to the new office where they can manually add the validated signature to their trusted identities.<br />
<br />
In the case of multiple signatures on the same document, the software clearly identifies the signatures that have not been validated as shown in figure 4 below.<br />
<br />
<br />
[[File:IM14Fig4.png|200px|thumb|center|alt text]]<br />
<br />
<br />
The software also automatically tracks all changes made to the document. This is important because by the very act of signing a document, the document has changed from the version the first person saw. Any major changes to the document that affect the integrety of the encrypted digital signatures will invalidate or delete the signatures, but minor changes like multiple signers will just be noted.<br />
<br />
Should an office receive a document or form 5600 that requries them to validate the digital signature the process is simple and straightforeward.<br />
<br />
The validation process is detailed on form 5600 and the receiver must verify at least two (2) of the four (4) federal signature authentication requirements outlined below:<br />
<br />
::a. The name of the sender is the same name expected.<br />
::b. E-mail from a company domain e-mail address.<br />
::c. Direct contact with sender verifying they sent the document with signature.<br />
::d. Verification via another method with provided details.<br />
<br />
The MDOT recipient of the document is then required to indicate which two methods were used to verify the signature is actually from the recipient and then confirm their validation efforts by placing their own digital signature on the form. This form is then routed to the central office for archiving and a copy of the completed form returned to the sender for their records or for submission to other offices until the central database is updated.<br />
::a. MDOT office staff that receives form 5600 will go through and complete the validation steps per the form instructions.<br />
<br />
::b. Once the DES is validated, the validating MDOT office staff will countersign form 5600. <br />
<br />
::c. MDOT office staff will then add the validated signature to their trusted identities. Instructions for manually adding a validated signature to your trusted identities can be found on the MDOT WIKI Construction Manual in Division 1 Supplemental Information, e-Sign section. <br />
[[E-Signature|http://mdotwiki.state.mi.us/construction/index.php/E-Signature]]<br />
<br />
:d. MDOT office staff will then submit the completed form 5600 to <br />
[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov] and also back to the submitting applicant.<br />
<br />
:3. MDOT-Central Office:<br />
<br />
::a. MDOT Central Office staff will receive form 5600 via the <br />
[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov] e-mail address. MDOT Central Office staff will then maintain these 5600 forms in a centralized server for archiving purposes, update export files of all previously validated DES, and send these validated DES out to MDOT staff periodically.<br />
<br />
If you have any questions, contact[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov]. Please share this information with consultants and local agencies within your area.<br />
<br />
====[[#Resources|Resources]]====<br />
<br />
{| class="wikitable"<br />
|-<br />
! File Name !! Description <br />
|-<br />
| [//{{SERVERNAME}}/images_construction/f/fa/Setting_Up_an_Electronic_Signature.pdf Setting Up an Electronic Signature] || Creating a Digital Identity with Adobe Acrobat|| <br />
|-<br />
| [//{{SERVERNAME}}/images_construction/5/5d/How_To_Add_A_Digital_Signature_Via_iPhone_422065_7.pdf How To Add A Digital Signature Via iPhone] || Creating a Digital Signature on any iOS smart device<br />
|-<br />
| [//{{SERVERNAME}}/images_construction/a/a6/E-sign_brochure.pdf E-sign brochure] || A brief outline concering various facets of E-signatures<br />
|-<br />
|[http://www.youtube.com/watch?v=pUIWvJgkw8E How to Digitally Sign a document with Adobe Reader]||A YouTube video published by Adobe about how to digitally sign a PDF file with the free Adobe Reader<br />
|-<br />
|[http://www.michigan.gov/documents/mdot/Applying_an_Image_To_Digital_Signature_422061_7.pdf Applying an Image To Digital Signature]|| How to import and insert an image to a digital signature<br />
|-<br />
|[http://www.michigan.gov/documents/mdot/Trusting_and_Validating_a_Digital_Signature_422068_7.pdf Trusting and Validating a Digital Siganture]|| How to trust and validate a signature in Adobe Acrobat<br />
|-<br />
|}<br />
<br />
<br />
<br />
[[Category: Construction Manual]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=E-Signature&diff=3950E-Signature2015-03-05T13:01:29Z<p>HarrisR18: /* Guidance for Non-MDOT Users */</p>
<hr />
<div><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Division 1 Supplemental Information'''</span></center><br />
<center><span STYLE="font: 30pt arial;">'''e-Signature'''</span></center><br />
<br />
<br />
====[[#General Information|General Information]]====<br />
<br />
According to the Code of Federal Regulation, electronic signatures are defined as a computer data compilation of any symbol or series of symbols executed, adopted, or authorized by an individual to be the legally binding equivalent of the individual's handwritten signature. A specific type of electronic signature is digital signatures. Digital signatures are defined as an electronic signature based upon cryptographic methods of originator authentication, computed by using a set of rules and a set of parameters such that the identity of the signer and the integrity of the data can be verified. <br />
<br />
An entity such as a computer user can be assigned a unique digital identification. This digital identification is composed of a public key, a private key, and a digital certificate. As their names suggest, the public key should be shared amongst users who wish to carry out transactions amongst themselves, while the private key should be only known by its user. The digital certificate is used within a public-key infrastructure to allow a third-party certificate authority to verify that the digital certificate is correctly associated with that particular public key.<br />
<br />
As public keys are shared amongst a group of users, someone’s public key can be used to encrypt a document and their respective private key can be used to decrypt that document. Confidentiality and data integrity of the sent document can be practically guaranteed assuming if the recipient is the only one who knows their private key. Similarly, someone’s private key can be ‘embedded’ into a document to constitute an electronic signature, and the identity of the electronic signature may be verified by using that user’s public key. <br />
<br />
{{top}}<br />
<br />
====[[#Adoption at MDOT and Acceptable Uses|Adoption at MDOT and Acceptable Uses]]====<br />
The Michigan Attorney General’s office, in concurrence of the Federal Highway Administration, has issued a decision authorizing the Michigan Department of Transportation (MDOT) to use and accept digital signatures (see [http://www.michigan.gov/documents/mdot/MDOT_IM12-02_378056_7.pdf BOH IM 2012-02]).<br />
<br />
There are many standards available for digital signatures, but MDOT currently authorizes the use of PKCS#12 files for digital identification. This cryptographic standard requires the signer to enter their unique password each time they digitally sign a document. To digitally sign a document, you must first have a digital identification (ID). This ID can be obtained from various certification authorities, but MDOT will primarily use Adobe as a certification authority. [http://www.michigan.gov/documents/mdot/Setting_Up_an_Electronic_Signature_422066_7.pdf This PDF file] and [http://www.youtube.com/watch?v=pUIWvJgkw8E this YouTube video, produced by Adobe Acrobat,] shows how to create a digital ID on Adobe Reader.<br />
<br />
Digital signatures created with Adobe Software need to conform to the following style guidelines: <br />
*Graphic options shall be:<br />
**“Name” Or “Imported Graphic” (as outlined below)<br />
<br />
*Configure text shall be configured as:<br />
**Uncheck the adobe “logo”<br />
**Required to include: (“Name”, “Date”, “Location” and “Reason”)<br />
**Optional “Distinguished Name” (includes job title)<br />
**Optional for “labels”<br />
**“left to right”<br />
You may have multiple digital signature files configured for different purposes. It is even possible to configure a digital signature with an “Imported Graphic” (refer to this [http://www.michigan.gov/documents/mdot/Applying_an_Image_To_Digital_Signature_422061_7.pdf PDF]) containing an image of your scanned written signature or a scan of a professional license stamp. These are acceptable, but written signature images are not required and non-business related graphics are not acceptable.<br />
<br />
Similar to how handwritten signatures must be verified, it is the responsibility of the recipient of a electronically signed document to confirm the identity of the signer/sender before the electronic signature may be considered valid. The recipient should consider whether or not that the document was sent from a recognized e-mail account and that the expected signer has been previously validated. If you are unsure, then you can verify by contacting their place of business. Adobe Acrobat software has an integrated validation feature that stores validated signatures, meaning that the user does not need to validate those signatures again. This [http://www.michigan.gov/documents/mdot/Trusting_and_Validating_a_Digital_Signature_422068_7.pdf PDF] shows how to validate a signature.<br />
<br />
MDOT is working on integration of electronic signatures on mobile devices. There are several mobile applications that allow PDF files to be digitally signed using mobile devices, but as of now none have been authorized for employee use. Employees are encouraged to submit mobile applications to the E-Sign team of the Construction Field Services Division and to the Department of Technology, Management and Budget. This [http://www.michigan.gov/documents/mdot/How_To_Add_A_Digital_Signature_Via_iPhone_422065_7.pdf PDF] shows how to digitally sign a PDF file on an iPhone.<br />
<br />
It is important to note that for records retention and archiving purposes whenever digital signatures are used on documents, the electronic file (usually PDF) is considered the original legal document. Printouts of the document containing digital signatures are considered copies, so the signed electronic file must be retained and follow the relevant approved records retention procedures. MDOT will address the records storage issue through the requirement that all electronically signed documents must be placed in the project directory in the ProjectWise document management program. The E-construction [http://mdotwiki.state.mi.us/construction/index.php/E-Construction wiki page] contains more information regarding ProjectWise. <br />
{{top}}<br />
<br />
====[[#Guidance for Non-MDOT Users|Guidance for Non-MDOT Users]]====<br />
<br />
An individual’s digital signature must be validated before MDOT can accept the signature. [http://mdotcf.state.mi.us/public/webforms/public/5600.pdf Form 5600] for contractors and [http://mdotcf.state.mi.us/public/webforms/public/5600A.pdf Form 5600A] for consultants allows an individual to submit their digital signature to MDOT. When you select the signature box when filling out these forms, you can use an existing digital ID or you can create a new ID. There are many ways an individual can obtain a digital ID, but the preferred way is to use Adobe software. These forms will be on file with MDOT until the individual’s digital signature certificate expires or until such time as the individual needs to create a new digital signature.<br />
<br />
====[[#What is Digital Signature Validation and why does it matter?<br />
| What is Digital Signature Validation and why does it matter?<br />
]]====<br />
<br />
All signatures must be authenticated to determine the identity of the document signer(s) and it is the legal requirement that anyone receiving a signature from an external party must authenticate the signature on the document they receive (paper or electronic). While handwritten signatures have visual indicators that help us determine someone’s real signature, the digital signature process is much faster and more secure. However, digital signatures can also be falsely created by other parties and made to look very similar to the authentic digital signatures, so care must be taken to determine the true identity of the signers. The process to determine the authenticity of digital signatures is referred to as signature validation.<br />
<br />
Validation is the process that authenticates the electronic signature on a document and compares it to the known validated signature on file.<br />
<br />
In general, the electronic signature validation process occurs primarily in the background of the software and only requires us to take action the first time a signature is received. A valid digital signature proves that the message was created by a known sender; such that the sender cannot deny having sent the message (authentication and non-repudiation) and that the message was not altered in transit (integrity). This is accomplished by the use of an algorithm that creates unique encrypted codes associated with the digital signature for the user. In general, each digital signature has two main components. The first is a private key code that is encrypted into the signature which is essentially the user’s password used to affix their signature. The second component is called the public key code which is a unique complex code embedded into the signature that allows other parties to easily authenticate the true identity of the signer. Each digital signatures public code is unique to the digital signature, not the person, thus if you have two digital signatures each has its own unique code, they are not the same. When a sender signs a document their private key remains with them, but the public key is embedded into the signature on the document. When the document is sent to the recipient, the recipient’s computer compares the unique public code in the signature to the list of known validated signature codes. If the codes match then the signature is considered valid and proves the signature was made by the sender. If the codes do not match, the software indicates the signature has not been validated. If this occurs the recipient is required to perform the validation process as described in the next section of this BOH IM. (Note the graphic process describing the validation process is presented in Attachment 1; e-Signature Validation Process Overview of this BOH IM.)<br />
<br />
Effective immediately, the process for validating Digital Electronic Signature (DES) received by MDOT from any external party will be as follows:<br />
<br />
:1. External Parties:<br />
<br />
::a. All external parties (non-MDOT/FHWA), intending to use DES on any documents to be submitted to MDOT, must submit form 5600 Statement of Digital Electronic Signature Validation to the local MDOT office for validation of the DES prior to (or concurrent with) the DES being used on any documents submitted to MDOT.<br />
<br />
::b. Form 5600 must be submitted for each individual DES the first time the signature is used on a project. This can be submitted concurrently with a document; however, the document will not be accepted until the validation process has been completed.<br />
<br />
::c. Most DES certificates expire after four (4) years from the initial date of the DES creation. It is the responsibility of the signature creator to maintain their DES and create a new DES when their current DES expires. Form 5600, once validated, will allow the use of the DES on other documents submitted to MDOT until the DES expires (including on other projects or in other offices).<br />
<br />
::d. If the DES owner changes employment, position, responsibilities, forgets the DES password, or loses the DES file, this will require that a new form 5600 be submitted for the new signature.<br />
<br />
:2. MDOT Office:<br />
<br />
Any document received by MDOT containing a DES must be checked for proper validation prior to acceptance. This can be confirmed via the blue signature panel validation process at the top of the document in Adobe Acrobat (Figure 1).<br />
<br />
Figure 1: Screen showing blue signature panel in Adobe Standard XI<br />
<br />
[[File:IM14Fig1.png|200px|thumb|center|alt text]]<br />
<br />
<br />
If the digital electronic signatures on the document have already been authenticated, the software will clearly confirm this with the green checkmark as shown below in Figure 2.<br />
<br />
[[File:IM14Fig2.png|200px|thumb|center|alt text]]<br />
<br />
<br />
If electronic documents come into the office with a non-validated DES, (figure 3 below), <br />
<br />
[[File:IM14Fig3.png|200px|thumb|center|alt text]]<br />
<br />
then the office must determine the validity of the document signers. If the signature does not match the previously validated signature codes on file the office must reject the document until a new form 5600 is submitted and the DES can be validated. '''It is the legal responsibility of the first person who receives any signature to verify the validity of the signature before accepting any documents.''' After the signature has been validated and added to the trusted list of validated signatures, the software will re-validate and display the green check mark. The completion of the form 5600 is only required when a signature is first used, subsequent documents will be validated automatically for that user. It may take a while for the central office database updates to be distributed to all other users, so until that occurs a signer can send along a copy of the fully completed form 5600 to the new office where they can manually add the validated signature to their trusted identities.<br />
<br />
In the case of multiple signatures on the same document, the software clearly identifies the signatures that have not been validated as shown in figure 4 below.<br />
<br />
<br />
[[File:IM14Fig4.png|200px|thumb|center|alt text]]<br />
<br />
<br />
The software also automatically tracks all changes made to the document. This is important because by the very act of signing a document, the document has changed from the version the first person saw. Any major changes to the document that affect the integrety of the encrypted digital signatures will invalidate or delete the signatures, but minor changes like multiple signers will just be noted.<br />
<br />
Should an office receive a document or form 5600 that requries them to validate the digital signature the process is simple and straightforeward.<br />
<br />
The validation process is detailed on form 5600 and the receiver must verify at least two (2) of the four (4) federal signature authentication requirements outlined below:<br />
<br />
::a. The name of the sender is the same name expected.<br />
::b. E-mail from a company domain e-mail address.<br />
::c. Direct contact with sender verifying they sent the document with signature.<br />
::d. Verification via another method with provided details.<br />
<br />
The MDOT recipient of the document is then required to indicate which two methods were used to verify the signature is actually from the recipient and then confirm their validation efforts by placing their own digital signature on the form. This form is then routed to the central office for archiving and a copy of the completed form returned to the sender for their records or for submission to other offices until the central database is updated.<br />
::a. MDOT office staff that receives form 5600 will go through and complete the validation steps per the form instructions.<br />
<br />
::b. Once the DES is validated, the validating MDOT office staff will countersign form 5600. <br />
<br />
::c. MDOT office staff will then add the validated signature to their trusted identities. Instructions for manually adding a validated signature to your trusted identities can be found on the MDOT WIKI Construction Manual in Division 1 Supplemental Information, e-Sign section. <br />
[[E-Signature|http://mdotwiki.state.mi.us/construction/index.php/E-Signature]]<br />
<br />
:d. MDOT office staff will then submit the completed form 5600 to <br />
[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov] and also back to the submitting applicant.<br />
<br />
:3. MDOT-Central Office:<br />
<br />
::a. MDOT Central Office staff will receive form 5600 via the <br />
[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov] e-mail address. MDOT Central Office staff will then maintain these 5600 forms in a centralized server for archiving purposes, update export files of all previously validated DES, and send these validated DES out to MDOT staff periodically.<br />
<br />
If you have any questions, contact[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov]. Please share this information with consultants and local agencies within your area.<br />
<br />
====[[#Resources|Resources]]====<br />
<br />
{| class="wikitable"<br />
|-<br />
! File Name !! Description <br />
|-<br />
| [//{{SERVERNAME}}/images_construction/f/fa/Setting_Up_an_Electronic_Signature.pdf Setting Up an Electronic Signature] || Creating a Digital Identity with Adobe Acrobat|| <br />
|-<br />
| [//{{SERVERNAME}}/images_construction/5/5d/How_To_Add_A_Digital_Signature_Via_iPhone_422065_7.pdf How To Add A Digital Signature Via iPhone] || Creating a Digital Signature on any iOS smart device<br />
|-<br />
| [//{{SERVERNAME}}/images_construction/a/a6/E-sign_brochure.pdf E-sign brochure] || A brief outline concering various facets of E-signatures<br />
|-<br />
|[http://www.youtube.com/watch?v=pUIWvJgkw8E How to Digitally Sign a document with Adobe Reader]||A YouTube video published by Adobe about how to digitally sign a PDF file with the free Adobe Reader<br />
|-<br />
|[http://www.michigan.gov/documents/mdot/Applying_an_Image_To_Digital_Signature_422061_7.pdf Applying an Image To Digital Signature]|| How to import and insert an image to a digital signature<br />
|-<br />
|[http://www.michigan.gov/documents/mdot/Trusting_and_Validating_a_Digital_Signature_422068_7.pdf Trusting and Validating a Digital Siganture]|| How to trust and validate a signature in Adobe Acrobat<br />
|-<br />
|}<br />
<br />
<br />
<br />
[[Category: Construction Manual]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=E-Signature&diff=3949E-Signature2015-03-05T13:01:05Z<p>HarrisR18: /* Article 4 */</p>
<hr />
<div><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Division 1 Supplemental Information'''</span></center><br />
<center><span STYLE="font: 30pt arial;">'''e-Signature'''</span></center><br />
<br />
<br />
====[[#General Information|General Information]]====<br />
<br />
According to the Code of Federal Regulation, electronic signatures are defined as a computer data compilation of any symbol or series of symbols executed, adopted, or authorized by an individual to be the legally binding equivalent of the individual's handwritten signature. A specific type of electronic signature is digital signatures. Digital signatures are defined as an electronic signature based upon cryptographic methods of originator authentication, computed by using a set of rules and a set of parameters such that the identity of the signer and the integrity of the data can be verified. <br />
<br />
An entity such as a computer user can be assigned a unique digital identification. This digital identification is composed of a public key, a private key, and a digital certificate. As their names suggest, the public key should be shared amongst users who wish to carry out transactions amongst themselves, while the private key should be only known by its user. The digital certificate is used within a public-key infrastructure to allow a third-party certificate authority to verify that the digital certificate is correctly associated with that particular public key.<br />
<br />
As public keys are shared amongst a group of users, someone’s public key can be used to encrypt a document and their respective private key can be used to decrypt that document. Confidentiality and data integrity of the sent document can be practically guaranteed assuming if the recipient is the only one who knows their private key. Similarly, someone’s private key can be ‘embedded’ into a document to constitute an electronic signature, and the identity of the electronic signature may be verified by using that user’s public key. <br />
<br />
{{top}}<br />
<br />
====[[#Adoption at MDOT and Acceptable Uses|Adoption at MDOT and Acceptable Uses]]====<br />
The Michigan Attorney General’s office, in concurrence of the Federal Highway Administration, has issued a decision authorizing the Michigan Department of Transportation (MDOT) to use and accept digital signatures (see [http://www.michigan.gov/documents/mdot/MDOT_IM12-02_378056_7.pdf BOH IM 2012-02]).<br />
<br />
There are many standards available for digital signatures, but MDOT currently authorizes the use of PKCS#12 files for digital identification. This cryptographic standard requires the signer to enter their unique password each time they digitally sign a document. To digitally sign a document, you must first have a digital identification (ID). This ID can be obtained from various certification authorities, but MDOT will primarily use Adobe as a certification authority. [http://www.michigan.gov/documents/mdot/Setting_Up_an_Electronic_Signature_422066_7.pdf This PDF file] and [http://www.youtube.com/watch?v=pUIWvJgkw8E this YouTube video, produced by Adobe Acrobat,] shows how to create a digital ID on Adobe Reader.<br />
<br />
Digital signatures created with Adobe Software need to conform to the following style guidelines: <br />
*Graphic options shall be:<br />
**“Name” Or “Imported Graphic” (as outlined below)<br />
<br />
*Configure text shall be configured as:<br />
**Uncheck the adobe “logo”<br />
**Required to include: (“Name”, “Date”, “Location” and “Reason”)<br />
**Optional “Distinguished Name” (includes job title)<br />
**Optional for “labels”<br />
**“left to right”<br />
You may have multiple digital signature files configured for different purposes. It is even possible to configure a digital signature with an “Imported Graphic” (refer to this [http://www.michigan.gov/documents/mdot/Applying_an_Image_To_Digital_Signature_422061_7.pdf PDF]) containing an image of your scanned written signature or a scan of a professional license stamp. These are acceptable, but written signature images are not required and non-business related graphics are not acceptable.<br />
<br />
Similar to how handwritten signatures must be verified, it is the responsibility of the recipient of a electronically signed document to confirm the identity of the signer/sender before the electronic signature may be considered valid. The recipient should consider whether or not that the document was sent from a recognized e-mail account and that the expected signer has been previously validated. If you are unsure, then you can verify by contacting their place of business. Adobe Acrobat software has an integrated validation feature that stores validated signatures, meaning that the user does not need to validate those signatures again. This [http://www.michigan.gov/documents/mdot/Trusting_and_Validating_a_Digital_Signature_422068_7.pdf PDF] shows how to validate a signature.<br />
<br />
MDOT is working on integration of electronic signatures on mobile devices. There are several mobile applications that allow PDF files to be digitally signed using mobile devices, but as of now none have been authorized for employee use. Employees are encouraged to submit mobile applications to the E-Sign team of the Construction Field Services Division and to the Department of Technology, Management and Budget. This [http://www.michigan.gov/documents/mdot/How_To_Add_A_Digital_Signature_Via_iPhone_422065_7.pdf PDF] shows how to digitally sign a PDF file on an iPhone.<br />
<br />
It is important to note that for records retention and archiving purposes whenever digital signatures are used on documents, the electronic file (usually PDF) is considered the original legal document. Printouts of the document containing digital signatures are considered copies, so the signed electronic file must be retained and follow the relevant approved records retention procedures. MDOT will address the records storage issue through the requirement that all electronically signed documents must be placed in the project directory in the ProjectWise document management program. The E-construction [http://mdotwiki.state.mi.us/construction/index.php/E-Construction wiki page] contains more information regarding ProjectWise. <br />
{{top}}<br />
<br />
====[[#Guidance for Non-MDOT Users|Guidance for Non-MDOT Users]]====<br />
<br />
An individual’s digital signature must be validated before MDOT can accept the signature. [http://mdotcf.state.mi.us/public/webforms/public/5600.pdf Form 5600] for contractors and [http://mdotcf.state.mi.us/public/webforms/public/5600A.pdf Form 5600A] for consultants allows an individual to submit their digital signature to MDOT. When you select the signature box when filling out these forms, you can use an existing digital ID or you can create a new ID. There are many ways an individual can obtain a digital ID, but the preferred way is to use Adobe software. These forms will be on file with MDOT until the individual’s digital signature certificate expires or until such time as the individual needs to create a new digital signature.<br />
====[[#What is Digital Signature Validation and why does it matter?<br />
| What is Digital Signature Validation and why does it matter?<br />
]]====<br />
<br />
All signatures must be authenticated to determine the identity of the document signer(s) and it is the legal requirement that anyone receiving a signature from an external party must authenticate the signature on the document they receive (paper or electronic). While handwritten signatures have visual indicators that help us determine someone’s real signature, the digital signature process is much faster and more secure. However, digital signatures can also be falsely created by other parties and made to look very similar to the authentic digital signatures, so care must be taken to determine the true identity of the signers. The process to determine the authenticity of digital signatures is referred to as signature validation.<br />
<br />
Validation is the process that authenticates the electronic signature on a document and compares it to the known validated signature on file.<br />
<br />
In general, the electronic signature validation process occurs primarily in the background of the software and only requires us to take action the first time a signature is received. A valid digital signature proves that the message was created by a known sender; such that the sender cannot deny having sent the message (authentication and non-repudiation) and that the message was not altered in transit (integrity). This is accomplished by the use of an algorithm that creates unique encrypted codes associated with the digital signature for the user. In general, each digital signature has two main components. The first is a private key code that is encrypted into the signature which is essentially the user’s password used to affix their signature. The second component is called the public key code which is a unique complex code embedded into the signature that allows other parties to easily authenticate the true identity of the signer. Each digital signatures public code is unique to the digital signature, not the person, thus if you have two digital signatures each has its own unique code, they are not the same. When a sender signs a document their private key remains with them, but the public key is embedded into the signature on the document. When the document is sent to the recipient, the recipient’s computer compares the unique public code in the signature to the list of known validated signature codes. If the codes match then the signature is considered valid and proves the signature was made by the sender. If the codes do not match, the software indicates the signature has not been validated. If this occurs the recipient is required to perform the validation process as described in the next section of this BOH IM. (Note the graphic process describing the validation process is presented in Attachment 1; e-Signature Validation Process Overview of this BOH IM.)<br />
<br />
Effective immediately, the process for validating Digital Electronic Signature (DES) received by MDOT from any external party will be as follows:<br />
<br />
:1. External Parties:<br />
<br />
::a. All external parties (non-MDOT/FHWA), intending to use DES on any documents to be submitted to MDOT, must submit form 5600 Statement of Digital Electronic Signature Validation to the local MDOT office for validation of the DES prior to (or concurrent with) the DES being used on any documents submitted to MDOT.<br />
<br />
::b. Form 5600 must be submitted for each individual DES the first time the signature is used on a project. This can be submitted concurrently with a document; however, the document will not be accepted until the validation process has been completed.<br />
<br />
::c. Most DES certificates expire after four (4) years from the initial date of the DES creation. It is the responsibility of the signature creator to maintain their DES and create a new DES when their current DES expires. Form 5600, once validated, will allow the use of the DES on other documents submitted to MDOT until the DES expires (including on other projects or in other offices).<br />
<br />
::d. If the DES owner changes employment, position, responsibilities, forgets the DES password, or loses the DES file, this will require that a new form 5600 be submitted for the new signature.<br />
<br />
:2. MDOT Office:<br />
<br />
Any document received by MDOT containing a DES must be checked for proper validation prior to acceptance. This can be confirmed via the blue signature panel validation process at the top of the document in Adobe Acrobat (Figure 1).<br />
<br />
Figure 1: Screen showing blue signature panel in Adobe Standard XI<br />
<br />
[[File:IM14Fig1.png|200px|thumb|center|alt text]]<br />
<br />
<br />
If the digital electronic signatures on the document have already been authenticated, the software will clearly confirm this with the green checkmark as shown below in Figure 2.<br />
<br />
[[File:IM14Fig2.png|200px|thumb|center|alt text]]<br />
<br />
<br />
If electronic documents come into the office with a non-validated DES, (figure 3 below), <br />
<br />
[[File:IM14Fig3.png|200px|thumb|center|alt text]]<br />
<br />
then the office must determine the validity of the document signers. If the signature does not match the previously validated signature codes on file the office must reject the document until a new form 5600 is submitted and the DES can be validated. '''It is the legal responsibility of the first person who receives any signature to verify the validity of the signature before accepting any documents.''' After the signature has been validated and added to the trusted list of validated signatures, the software will re-validate and display the green check mark. The completion of the form 5600 is only required when a signature is first used, subsequent documents will be validated automatically for that user. It may take a while for the central office database updates to be distributed to all other users, so until that occurs a signer can send along a copy of the fully completed form 5600 to the new office where they can manually add the validated signature to their trusted identities.<br />
<br />
In the case of multiple signatures on the same document, the software clearly identifies the signatures that have not been validated as shown in figure 4 below.<br />
<br />
<br />
[[File:IM14Fig4.png|200px|thumb|center|alt text]]<br />
<br />
<br />
The software also automatically tracks all changes made to the document. This is important because by the very act of signing a document, the document has changed from the version the first person saw. Any major changes to the document that affect the integrety of the encrypted digital signatures will invalidate or delete the signatures, but minor changes like multiple signers will just be noted.<br />
<br />
Should an office receive a document or form 5600 that requries them to validate the digital signature the process is simple and straightforeward.<br />
<br />
The validation process is detailed on form 5600 and the receiver must verify at least two (2) of the four (4) federal signature authentication requirements outlined below:<br />
<br />
::a. The name of the sender is the same name expected.<br />
::b. E-mail from a company domain e-mail address.<br />
::c. Direct contact with sender verifying they sent the document with signature.<br />
::d. Verification via another method with provided details.<br />
<br />
The MDOT recipient of the document is then required to indicate which two methods were used to verify the signature is actually from the recipient and then confirm their validation efforts by placing their own digital signature on the form. This form is then routed to the central office for archiving and a copy of the completed form returned to the sender for their records or for submission to other offices until the central database is updated.<br />
::a. MDOT office staff that receives form 5600 will go through and complete the validation steps per the form instructions.<br />
<br />
::b. Once the DES is validated, the validating MDOT office staff will countersign form 5600. <br />
<br />
::c. MDOT office staff will then add the validated signature to their trusted identities. Instructions for manually adding a validated signature to your trusted identities can be found on the MDOT WIKI Construction Manual in Division 1 Supplemental Information, e-Sign section. <br />
[[E-Signature|http://mdotwiki.state.mi.us/construction/index.php/E-Signature]]<br />
<br />
:d. MDOT office staff will then submit the completed form 5600 to <br />
[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov] and also back to the submitting applicant.<br />
<br />
:3. MDOT-Central Office:<br />
<br />
::a. MDOT Central Office staff will receive form 5600 via the <br />
[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov] e-mail address. MDOT Central Office staff will then maintain these 5600 forms in a centralized server for archiving purposes, update export files of all previously validated DES, and send these validated DES out to MDOT staff periodically.<br />
<br />
If you have any questions, contact[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov]. Please share this information with consultants and local agencies within your area.<br />
<br />
====[[#Resources|Resources]]====<br />
<br />
{| class="wikitable"<br />
|-<br />
! File Name !! Description <br />
|-<br />
| [//{{SERVERNAME}}/images_construction/f/fa/Setting_Up_an_Electronic_Signature.pdf Setting Up an Electronic Signature] || Creating a Digital Identity with Adobe Acrobat|| <br />
|-<br />
| [//{{SERVERNAME}}/images_construction/5/5d/How_To_Add_A_Digital_Signature_Via_iPhone_422065_7.pdf How To Add A Digital Signature Via iPhone] || Creating a Digital Signature on any iOS smart device<br />
|-<br />
| [//{{SERVERNAME}}/images_construction/a/a6/E-sign_brochure.pdf E-sign brochure] || A brief outline concering various facets of E-signatures<br />
|-<br />
|[http://www.youtube.com/watch?v=pUIWvJgkw8E How to Digitally Sign a document with Adobe Reader]||A YouTube video published by Adobe about how to digitally sign a PDF file with the free Adobe Reader<br />
|-<br />
|[http://www.michigan.gov/documents/mdot/Applying_an_Image_To_Digital_Signature_422061_7.pdf Applying an Image To Digital Signature]|| How to import and insert an image to a digital signature<br />
|-<br />
|[http://www.michigan.gov/documents/mdot/Trusting_and_Validating_a_Digital_Signature_422068_7.pdf Trusting and Validating a Digital Siganture]|| How to trust and validate a signature in Adobe Acrobat<br />
|-<br />
|}<br />
<br />
<br />
<br />
[[Category: Construction Manual]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=E-Signature&diff=3948E-Signature2015-03-05T12:58:54Z<p>HarrisR18: </p>
<hr />
<div><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Division 1 Supplemental Information'''</span></center><br />
<center><span STYLE="font: 30pt arial;">'''e-Signature'''</span></center><br />
<br />
<br />
====[[#General Information|General Information]]====<br />
<br />
According to the Code of Federal Regulation, electronic signatures are defined as a computer data compilation of any symbol or series of symbols executed, adopted, or authorized by an individual to be the legally binding equivalent of the individual's handwritten signature. A specific type of electronic signature is digital signatures. Digital signatures are defined as an electronic signature based upon cryptographic methods of originator authentication, computed by using a set of rules and a set of parameters such that the identity of the signer and the integrity of the data can be verified. <br />
<br />
An entity such as a computer user can be assigned a unique digital identification. This digital identification is composed of a public key, a private key, and a digital certificate. As their names suggest, the public key should be shared amongst users who wish to carry out transactions amongst themselves, while the private key should be only known by its user. The digital certificate is used within a public-key infrastructure to allow a third-party certificate authority to verify that the digital certificate is correctly associated with that particular public key.<br />
<br />
As public keys are shared amongst a group of users, someone’s public key can be used to encrypt a document and their respective private key can be used to decrypt that document. Confidentiality and data integrity of the sent document can be practically guaranteed assuming if the recipient is the only one who knows their private key. Similarly, someone’s private key can be ‘embedded’ into a document to constitute an electronic signature, and the identity of the electronic signature may be verified by using that user’s public key. <br />
<br />
{{top}}<br />
<br />
====[[#Adoption at MDOT and Acceptable Uses|Adoption at MDOT and Acceptable Uses]]====<br />
The Michigan Attorney General’s office, in concurrence of the Federal Highway Administration, has issued a decision authorizing the Michigan Department of Transportation (MDOT) to use and accept digital signatures (see [http://www.michigan.gov/documents/mdot/MDOT_IM12-02_378056_7.pdf BOH IM 2012-02]).<br />
<br />
There are many standards available for digital signatures, but MDOT currently authorizes the use of PKCS#12 files for digital identification. This cryptographic standard requires the signer to enter their unique password each time they digitally sign a document. To digitally sign a document, you must first have a digital identification (ID). This ID can be obtained from various certification authorities, but MDOT will primarily use Adobe as a certification authority. [http://www.michigan.gov/documents/mdot/Setting_Up_an_Electronic_Signature_422066_7.pdf This PDF file] and [http://www.youtube.com/watch?v=pUIWvJgkw8E this YouTube video, produced by Adobe Acrobat,] shows how to create a digital ID on Adobe Reader.<br />
<br />
Digital signatures created with Adobe Software need to conform to the following style guidelines: <br />
*Graphic options shall be:<br />
**“Name” Or “Imported Graphic” (as outlined below)<br />
<br />
*Configure text shall be configured as:<br />
**Uncheck the adobe “logo”<br />
**Required to include: (“Name”, “Date”, “Location” and “Reason”)<br />
**Optional “Distinguished Name” (includes job title)<br />
**Optional for “labels”<br />
**“left to right”<br />
You may have multiple digital signature files configured for different purposes. It is even possible to configure a digital signature with an “Imported Graphic” (refer to this [http://www.michigan.gov/documents/mdot/Applying_an_Image_To_Digital_Signature_422061_7.pdf PDF]) containing an image of your scanned written signature or a scan of a professional license stamp. These are acceptable, but written signature images are not required and non-business related graphics are not acceptable.<br />
<br />
Similar to how handwritten signatures must be verified, it is the responsibility of the recipient of a electronically signed document to confirm the identity of the signer/sender before the electronic signature may be considered valid. The recipient should consider whether or not that the document was sent from a recognized e-mail account and that the expected signer has been previously validated. If you are unsure, then you can verify by contacting their place of business. Adobe Acrobat software has an integrated validation feature that stores validated signatures, meaning that the user does not need to validate those signatures again. This [http://www.michigan.gov/documents/mdot/Trusting_and_Validating_a_Digital_Signature_422068_7.pdf PDF] shows how to validate a signature.<br />
<br />
MDOT is working on integration of electronic signatures on mobile devices. There are several mobile applications that allow PDF files to be digitally signed using mobile devices, but as of now none have been authorized for employee use. Employees are encouraged to submit mobile applications to the E-Sign team of the Construction Field Services Division and to the Department of Technology, Management and Budget. This [http://www.michigan.gov/documents/mdot/How_To_Add_A_Digital_Signature_Via_iPhone_422065_7.pdf PDF] shows how to digitally sign a PDF file on an iPhone.<br />
<br />
It is important to note that for records retention and archiving purposes whenever digital signatures are used on documents, the electronic file (usually PDF) is considered the original legal document. Printouts of the document containing digital signatures are considered copies, so the signed electronic file must be retained and follow the relevant approved records retention procedures. MDOT will address the records storage issue through the requirement that all electronically signed documents must be placed in the project directory in the ProjectWise document management program. The E-construction [http://mdotwiki.state.mi.us/construction/index.php/E-Construction wiki page] contains more information regarding ProjectWise. <br />
{{top}}<br />
<br />
====[[#Guidance for Non-MDOT Users|Guidance for Non-MDOT Users]]====<br />
<br />
An individual’s digital signature must be validated before MDOT can accept the signature. [http://mdotcf.state.mi.us/public/webforms/public/5600.pdf Form 5600] for contractors and [http://mdotcf.state.mi.us/public/webforms/public/5600A.pdf Form 5600A] for consultants allows an individual to submit their digital signature to MDOT. When you select the signature box when filling out these forms, you can use an existing digital ID or you can create a new ID. There are many ways an individual can obtain a digital ID, but the preferred way is to use Adobe software. These forms will be on file with MDOT until the individual’s digital signature certificate expires or until such time as the individual needs to create a new digital signature.<br />
====[[#Article 4|Article 4]]====<br />
<br />
'''What is Digital Signature Validation and why does it matter?'''<br />
<br />
All signatures must be authenticated to determine the identity of the document signer(s) and it is the legal requirement that anyone receiving a signature from an external party must authenticate the signature on the document they receive (paper or electronic). While handwritten signatures have visual indicators that help us determine someone’s real signature, the digital signature process is much faster and more secure. However, digital signatures can also be falsely created by other parties and made to look very similar to the authentic digital signatures, so care must be taken to determine the true identity of the signers. The process to determine the authenticity of digital signatures is referred to as signature validation.<br />
<br />
Validation is the process that authenticates the electronic signature on a document and compares it to the known validated signature on file.<br />
<br />
In general, the electronic signature validation process occurs primarily in the background of the software and only requires us to take action the first time a signature is received. A valid digital signature proves that the message was created by a known sender; such that the sender cannot deny having sent the message (authentication and non-repudiation) and that the message was not altered in transit (integrity). This is accomplished by the use of an algorithm that creates unique encrypted codes associated with the digital signature for the user. In general, each digital signature has two main components. The first is a private key code that is encrypted into the signature which is essentially the user’s password used to affix their signature. The second component is called the public key code which is a unique complex code embedded into the signature that allows other parties to easily authenticate the true identity of the signer. Each digital signatures public code is unique to the digital signature, not the person, thus if you have two digital signatures each has its own unique code, they are not the same. When a sender signs a document their private key remains with them, but the public key is embedded into the signature on the document. When the document is sent to the recipient, the recipient’s computer compares the unique public code in the signature to the list of known validated signature codes. If the codes match then the signature is considered valid and proves the signature was made by the sender. If the codes do not match, the software indicates the signature has not been validated. If this occurs the recipient is required to perform the validation process as described in the next section of this BOH IM. (Note the graphic process describing the validation process is presented in Attachment 1; e-Signature Validation Process Overview of this BOH IM.)<br />
<br />
Effective immediately, the process for validating Digital Electronic Signature (DES) received by MDOT from any external party will be as follows:<br />
<br />
:1. External Parties:<br />
<br />
::a. All external parties (non-MDOT/FHWA), intending to use DES on any documents to be submitted to MDOT, must submit form 5600 Statement of Digital Electronic Signature Validation to the local MDOT office for validation of the DES prior to (or concurrent with) the DES being used on any documents submitted to MDOT.<br />
<br />
::b. Form 5600 must be submitted for each individual DES the first time the signature is used on a project. This can be submitted concurrently with a document; however, the document will not be accepted until the validation process has been completed.<br />
<br />
::c. Most DES certificates expire after four (4) years from the initial date of the DES creation. It is the responsibility of the signature creator to maintain their DES and create a new DES when their current DES expires. Form 5600, once validated, will allow the use of the DES on other documents submitted to MDOT until the DES expires (including on other projects or in other offices).<br />
<br />
::d. If the DES owner changes employment, position, responsibilities, forgets the DES password, or loses the DES file, this will require that a new form 5600 be submitted for the new signature.<br />
<br />
:2. MDOT Office:<br />
<br />
Any document received by MDOT containing a DES must be checked for proper validation prior to acceptance. This can be confirmed via the blue signature panel validation process at the top of the document in Adobe Acrobat (Figure 1).<br />
<br />
Figure 1: Screen showing blue signature panel in Adobe Standard XI<br />
<br />
[[File:IM14Fig1.png|200px|thumb|center|alt text]]<br />
<br />
<br />
If the digital electronic signatures on the document have already been authenticated, the software will clearly confirm this with the green checkmark as shown below in Figure 2.<br />
<br />
[[File:IM14Fig2.png|200px|thumb|center|alt text]]<br />
<br />
<br />
If electronic documents come into the office with a non-validated DES, (figure 3 below), <br />
<br />
[[File:IM14Fig3.png|200px|thumb|center|alt text]]<br />
<br />
then the office must determine the validity of the document signers. If the signature does not match the previously validated signature codes on file the office must reject the document until a new form 5600 is submitted and the DES can be validated. '''It is the legal responsibility of the first person who receives any signature to verify the validity of the signature before accepting any documents.''' After the signature has been validated and added to the trusted list of validated signatures, the software will re-validate and display the green check mark. The completion of the form 5600 is only required when a signature is first used, subsequent documents will be validated automatically for that user. It may take a while for the central office database updates to be distributed to all other users, so until that occurs a signer can send along a copy of the fully completed form 5600 to the new office where they can manually add the validated signature to their trusted identities.<br />
<br />
In the case of multiple signatures on the same document, the software clearly identifies the signatures that have not been validated as shown in figure 4 below.<br />
<br />
<br />
[[File:IM14Fig4.png|200px|thumb|center|alt text]]<br />
<br />
<br />
The software also automatically tracks all changes made to the document. This is important because by the very act of signing a document, the document has changed from the version the first person saw. Any major changes to the document that affect the integrety of the encrypted digital signatures will invalidate or delete the signatures, but minor changes like multiple signers will just be noted.<br />
<br />
Should an office receive a document or form 5600 that requries them to validate the digital signature the process is simple and straightforeward.<br />
<br />
The validation process is detailed on form 5600 and the receiver must verify at least two (2) of the four (4) federal signature authentication requirements outlined below:<br />
<br />
::a. The name of the sender is the same name expected.<br />
::b. E-mail from a company domain e-mail address.<br />
::c. Direct contact with sender verifying they sent the document with signature.<br />
::d. Verification via another method with provided details.<br />
<br />
The MDOT recipient of the document is then required to indicate which two methods were used to verify the signature is actually from the recipient and then confirm their validation efforts by placing their own digital signature on the form. This form is then routed to the central office for archiving and a copy of the completed form returned to the sender for their records or for submission to other offices until the central database is updated.<br />
::a. MDOT office staff that receives form 5600 will go through and complete the validation steps per the form instructions.<br />
<br />
::b. Once the DES is validated, the validating MDOT office staff will countersign form 5600. <br />
<br />
::c. MDOT office staff will then add the validated signature to their trusted identities. Instructions for manually adding a validated signature to your trusted identities can be found on the MDOT WIKI Construction Manual in Division 1 Supplemental Information, e-Sign section. <br />
[[E-Signature|http://mdotwiki.state.mi.us/construction/index.php/E-Signature]]<br />
<br />
:d. MDOT office staff will then submit the completed form 5600 to <br />
[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov] and also back to the submitting applicant.<br />
<br />
:3. MDOT-Central Office:<br />
<br />
::a. MDOT Central Office staff will receive form 5600 via the <br />
[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov] e-mail address. MDOT Central Office staff will then maintain these 5600 forms in a centralized server for archiving purposes, update export files of all previously validated DES, and send these validated DES out to MDOT staff periodically.<br />
<br />
If you have any questions, contact[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov]. Please share this information with consultants and local agencies within your area.<br />
<br />
<br />
<br />
<br />
<br />
====[[#Resources|Resources]]====<br />
<br />
{| class="wikitable"<br />
|-<br />
! File Name !! Description <br />
|-<br />
| [//{{SERVERNAME}}/images_construction/f/fa/Setting_Up_an_Electronic_Signature.pdf Setting Up an Electronic Signature] || Creating a Digital Identity with Adobe Acrobat|| <br />
|-<br />
| [//{{SERVERNAME}}/images_construction/5/5d/How_To_Add_A_Digital_Signature_Via_iPhone_422065_7.pdf How To Add A Digital Signature Via iPhone] || Creating a Digital Signature on any iOS smart device<br />
|-<br />
| [//{{SERVERNAME}}/images_construction/a/a6/E-sign_brochure.pdf E-sign brochure] || A brief outline concering various facets of E-signatures<br />
|-<br />
|[http://www.youtube.com/watch?v=pUIWvJgkw8E How to Digitally Sign a document with Adobe Reader]||A YouTube video published by Adobe about how to digitally sign a PDF file with the free Adobe Reader<br />
|-<br />
|[http://www.michigan.gov/documents/mdot/Applying_an_Image_To_Digital_Signature_422061_7.pdf Applying an Image To Digital Signature]|| How to import and insert an image to a digital signature<br />
|-<br />
|[http://www.michigan.gov/documents/mdot/Trusting_and_Validating_a_Digital_Signature_422068_7.pdf Trusting and Validating a Digital Siganture]|| How to trust and validate a signature in Adobe Acrobat<br />
|-<br />
|}<br />
<br />
<br />
<br />
[[Category: Construction Manual]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=File:IM14Fig4.png&diff=3947File:IM14Fig4.png2015-03-05T12:54:10Z<p>HarrisR18: </p>
<hr />
<div></div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=File:IM14Fig3.png&diff=3946File:IM14Fig3.png2015-03-05T12:53:42Z<p>HarrisR18: </p>
<hr />
<div></div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=File:IM14Fig2.png&diff=3945File:IM14Fig2.png2015-03-05T12:53:01Z<p>HarrisR18: </p>
<hr />
<div></div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=File:IM14Fig1.png&diff=3944File:IM14Fig1.png2015-03-05T12:52:22Z<p>HarrisR18: </p>
<hr />
<div></div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=E-Signature&diff=3943E-Signature2015-03-05T12:49:00Z<p>HarrisR18: </p>
<hr />
<div><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Division 1 Supplemental Information'''</span></center><br />
<center><span STYLE="font: 30pt arial;">'''e-Signature'''</span></center><br />
<br />
<br />
====[[#General Information|General Information]]====<br />
<br />
According to the Code of Federal Regulation, electronic signatures are defined as a computer data compilation of any symbol or series of symbols executed, adopted, or authorized by an individual to be the legally binding equivalent of the individual's handwritten signature. A specific type of electronic signature is digital signatures. Digital signatures are defined as an electronic signature based upon cryptographic methods of originator authentication, computed by using a set of rules and a set of parameters such that the identity of the signer and the integrity of the data can be verified. <br />
<br />
An entity such as a computer user can be assigned a unique digital identification. This digital identification is composed of a public key, a private key, and a digital certificate. As their names suggest, the public key should be shared amongst users who wish to carry out transactions amongst themselves, while the private key should be only known by its user. The digital certificate is used within a public-key infrastructure to allow a third-party certificate authority to verify that the digital certificate is correctly associated with that particular public key.<br />
<br />
As public keys are shared amongst a group of users, someone’s public key can be used to encrypt a document and their respective private key can be used to decrypt that document. Confidentiality and data integrity of the sent document can be practically guaranteed assuming if the recipient is the only one who knows their private key. Similarly, someone’s private key can be ‘embedded’ into a document to constitute an electronic signature, and the identity of the electronic signature may be verified by using that user’s public key. <br />
<br />
{{top}}<br />
<br />
====[[#Adoption at MDOT and Acceptable Uses|Adoption at MDOT and Acceptable Uses]]====<br />
The Michigan Attorney General’s office, in concurrence of the Federal Highway Administration, has issued a decision authorizing the Michigan Department of Transportation (MDOT) to use and accept digital signatures (see [http://www.michigan.gov/documents/mdot/MDOT_IM12-02_378056_7.pdf BOH IM 2012-02]).<br />
<br />
There are many standards available for digital signatures, but MDOT currently authorizes the use of PKCS#12 files for digital identification. This cryptographic standard requires the signer to enter their unique password each time they digitally sign a document. To digitally sign a document, you must first have a digital identification (ID). This ID can be obtained from various certification authorities, but MDOT will primarily use Adobe as a certification authority. [http://www.michigan.gov/documents/mdot/Setting_Up_an_Electronic_Signature_422066_7.pdf This PDF file] and [http://www.youtube.com/watch?v=pUIWvJgkw8E this YouTube video, produced by Adobe Acrobat,] shows how to create a digital ID on Adobe Reader.<br />
<br />
Digital signatures created with Adobe Software need to conform to the following style guidelines: <br />
*Graphic options shall be:<br />
**“Name” Or “Imported Graphic” (as outlined below)<br />
<br />
*Configure text shall be configured as:<br />
**Uncheck the adobe “logo”<br />
**Required to include: (“Name”, “Date”, “Location” and “Reason”)<br />
**Optional “Distinguished Name” (includes job title)<br />
**Optional for “labels”<br />
**“left to right”<br />
You may have multiple digital signature files configured for different purposes. It is even possible to configure a digital signature with an “Imported Graphic” (refer to this [http://www.michigan.gov/documents/mdot/Applying_an_Image_To_Digital_Signature_422061_7.pdf PDF]) containing an image of your scanned written signature or a scan of a professional license stamp. These are acceptable, but written signature images are not required and non-business related graphics are not acceptable.<br />
<br />
Similar to how handwritten signatures must be verified, it is the responsibility of the recipient of a electronically signed document to confirm the identity of the signer/sender before the electronic signature may be considered valid. The recipient should consider whether or not that the document was sent from a recognized e-mail account and that the expected signer has been previously validated. If you are unsure, then you can verify by contacting their place of business. Adobe Acrobat software has an integrated validation feature that stores validated signatures, meaning that the user does not need to validate those signatures again. This [http://www.michigan.gov/documents/mdot/Trusting_and_Validating_a_Digital_Signature_422068_7.pdf PDF] shows how to validate a signature.<br />
<br />
MDOT is working on integration of electronic signatures on mobile devices. There are several mobile applications that allow PDF files to be digitally signed using mobile devices, but as of now none have been authorized for employee use. Employees are encouraged to submit mobile applications to the E-Sign team of the Construction Field Services Division and to the Department of Technology, Management and Budget. This [http://www.michigan.gov/documents/mdot/How_To_Add_A_Digital_Signature_Via_iPhone_422065_7.pdf PDF] shows how to digitally sign a PDF file on an iPhone.<br />
<br />
It is important to note that for records retention and archiving purposes whenever digital signatures are used on documents, the electronic file (usually PDF) is considered the original legal document. Printouts of the document containing digital signatures are considered copies, so the signed electronic file must be retained and follow the relevant approved records retention procedures. MDOT will address the records storage issue through the requirement that all electronically signed documents must be placed in the project directory in the ProjectWise document management program. The E-construction [http://mdotwiki.state.mi.us/construction/index.php/E-Construction wiki page] contains more information regarding ProjectWise. <br />
{{top}}<br />
<br />
====[[#Guidance for Non-MDOT Users|Guidance for Non-MDOT Users]]====<br />
<br />
An individual’s digital signature must be validated before MDOT can accept the signature. [http://mdotcf.state.mi.us/public/webforms/public/5600.pdf Form 5600] for contractors and [http://mdotcf.state.mi.us/public/webforms/public/5600A.pdf Form 5600A] for consultants allows an individual to submit their digital signature to MDOT. When you select the signature box when filling out these forms, you can use an existing digital ID or you can create a new ID. There are many ways an individual can obtain a digital ID, but the preferred way is to use Adobe software. These forms will be on file with MDOT until the individual’s digital signature certificate expires or until such time as the individual needs to create a new digital signature.<br />
====[[#Article 4|Article 4]]====<br />
<br />
'''What is Digital Signature Validation and why does it matter?'''<br />
<br />
All signatures must be authenticated to determine the identity of the document signer(s) and it is the legal requirement that anyone receiving a signature from an external party must authenticate the signature on the document they receive (paper or electronic). While handwritten signatures have visual indicators that help us determine someone’s real signature, the digital signature process is much faster and more secure. However, digital signatures can also be falsely created by other parties and made to look very similar to the authentic digital signatures, so care must be taken to determine the true identity of the signers. The process to determine the authenticity of digital signatures is referred to as signature validation.<br />
<br />
Validation is the process that authenticates the electronic signature on a document and compares it to the known validated signature on file.<br />
<br />
In general, the electronic signature validation process occurs primarily in the background of the software and only requires us to take action the first time a signature is received. A valid digital signature proves that the message was created by a known sender; such that the sender cannot deny having sent the message (authentication and non-repudiation) and that the message was not altered in transit (integrity). This is accomplished by the use of an algorithm that creates unique encrypted codes associated with the digital signature for the user. In general, each digital signature has two main components. The first is a private key code that is encrypted into the signature which is essentially the user’s password used to affix their signature. The second component is called the public key code which is a unique complex code embedded into the signature that allows other parties to easily authenticate the true identity of the signer. Each digital signatures public code is unique to the digital signature, not the person, thus if you have two digital signatures each has its own unique code, they are not the same. When a sender signs a document their private key remains with them, but the public key is embedded into the signature on the document. When the document is sent to the recipient, the recipient’s computer compares the unique public code in the signature to the list of known validated signature codes. If the codes match then the signature is considered valid and proves the signature was made by the sender. If the codes do not match, the software indicates the signature has not been validated. If this occurs the recipient is required to perform the validation process as described in the next section of this BOH IM. (Note the graphic process describing the validation process is presented in Attachment 1; e-Signature Validation Process Overview of this BOH IM.)<br />
<br />
Effective immediately, the process for validating Digital Electronic Signature (DES) received by MDOT from any external party will be as follows:<br />
<br />
:1. External Parties:<br />
<br />
::a. All external parties (non-MDOT/FHWA), intending to use DES on any documents to be submitted to MDOT, must submit form 5600 Statement of Digital Electronic Signature Validation to the local MDOT office for validation of the DES prior to (or concurrent with) the DES being used on any documents submitted to MDOT.<br />
<br />
::b. Form 5600 must be submitted for each individual DES the first time the signature is used on a project. This can be submitted concurrently with a document; however, the document will not be accepted until the validation process has been completed.<br />
<br />
::c. Most DES certificates expire after four (4) years from the initial date of the DES creation. It is the responsibility of the signature creator to maintain their DES and create a new DES when their current DES expires. Form 5600, once validated, will allow the use of the DES on other documents submitted to MDOT until the DES expires (including on other projects or in other offices).<br />
<br />
::d. If the DES owner changes employment, position, responsibilities, forgets the DES password, or loses the DES file, this will require that a new form 5600 be submitted for the new signature.<br />
<br />
:2. MDOT Office:<br />
<br />
Any document received by MDOT containing a DES must be checked for proper validation prior to acceptance. This can be confirmed via the blue signature panel validation process at the top of the document in Adobe Acrobat (Figure 1).<br />
<br />
Figure 1: Screen showing blue signature panel in Adobe Standard XI<br />
<br />
<br />
<br />
<br />
If the digital electronic signatures on the document have already been authenticated, the software will clearly confirm this with the green checkmark as shown below in Figure 2.<br />
<br />
<br />
<br />
<br />
If electronic documents come into the office with a non-validated DES, (figure 3 below), <br />
<br />
<br />
<br />
<br />
<br />
then the office must determine the validity of the document signers. If the signature does not match the previously validated signature codes on file the office must reject the document until a new form 5600 is submitted and the DES can be validated. '''It is the legal responsibility of the first person who receives any signature to verify the validity of the signature before accepting any documents.''' After the signature has been validated and added to the trusted list of validated signatures, the software will re-validate and display the green check mark. The completion of the form 5600 is only required when a signature is first used, subsequent documents will be validated automatically for that user. It may take a while for the central office database updates to be distributed to all other users, so until that occurs a signer can send along a copy of the fully completed form 5600 to the new office where they can manually add the validated signature to their trusted identities.<br />
<br />
In the case of multiple signatures on the same document, the software clearly identifies the signatures that have not been validated as shown in figure 4 below.<br />
<br />
<br />
<br />
<br />
<br />
The software also automatically tracks all changes made to the document. This is important because by the very act of signing a document, the document has changed from the version the first person saw. Any major changes to the document that affect the integrety of the encrypted digital signatures will invalidate or delete the signatures, but minor changes like multiple signers will just be noted.<br />
<br />
Should an office receive a document or form 5600 that requries them to validate the digital signature the process is simple and straightforeward.<br />
<br />
The validation process is detailed on form 5600 and the receiver must verify at least two (2) of the four (4) federal signature authentication requirements outlined below:<br />
<br />
::a. The name of the sender is the same name expected.<br />
::b. E-mail from a company domain e-mail address.<br />
::c. Direct contact with sender verifying they sent the document with signature.<br />
::d. Verification via another method with provided details.<br />
<br />
The MDOT recipient of the document is then required to indicate which two methods were used to verify the signature is actually from the recipient and then confirm their validation efforts by placing their own digital signature on the form. This form is then routed to the central office for archiving and a copy of the completed form returned to the sender for their records or for submission to other offices until the central database is updated.<br />
::a. MDOT office staff that receives form 5600 will go through and complete the validation steps per the form instructions.<br />
<br />
::b. Once the DES is validated, the validating MDOT office staff will countersign form 5600. <br />
<br />
::c. MDOT office staff will then add the validated signature to their trusted identities. Instructions for manually adding a validated signature to your trusted identities can be found on the MDOT WIKI Construction Manual in Division 1 Supplemental Information, e-Sign section. <br />
[[E-Signature|http://mdotwiki.state.mi.us/construction/index.php/E-Signature]]<br />
<br />
:d. MDOT office staff will then submit the completed form 5600 to <br />
[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov] and also back to the submitting applicant.<br />
<br />
:3. MDOT-Central Office:<br />
<br />
::a. MDOT Central Office staff will receive form 5600 via the <br />
[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov] e-mail address. MDOT Central Office staff will then maintain these 5600 forms in a centralized server for archiving purposes, update export files of all previously validated DES, and send these validated DES out to MDOT staff periodically.<br />
<br />
If you have any questions, contact[mailto:MDOT-eSign@michigan.gov MDOT-eSign@michigan.gov]. Please share this information with consultants and local agencies within your area.<br />
<br />
<br />
<br />
<br />
<br />
====[[#Resources|Resources]]====<br />
<br />
{| class="wikitable"<br />
|-<br />
! File Name !! Description <br />
|-<br />
| [//{{SERVERNAME}}/images_construction/f/fa/Setting_Up_an_Electronic_Signature.pdf Setting Up an Electronic Signature] || Creating a Digital Identity with Adobe Acrobat|| <br />
|-<br />
| [//{{SERVERNAME}}/images_construction/5/5d/How_To_Add_A_Digital_Signature_Via_iPhone_422065_7.pdf How To Add A Digital Signature Via iPhone] || Creating a Digital Signature on any iOS smart device<br />
|-<br />
| [//{{SERVERNAME}}/images_construction/a/a6/E-sign_brochure.pdf E-sign brochure] || A brief outline concering various facets of E-signatures<br />
|-<br />
|[http://www.youtube.com/watch?v=pUIWvJgkw8E How to Digitally Sign a document with Adobe Reader]||A YouTube video published by Adobe about how to digitally sign a PDF file with the free Adobe Reader<br />
|-<br />
|[http://www.michigan.gov/documents/mdot/Applying_an_Image_To_Digital_Signature_422061_7.pdf Applying an Image To Digital Signature]|| How to import and insert an image to a digital signature<br />
|-<br />
|[http://www.michigan.gov/documents/mdot/Trusting_and_Validating_a_Digital_Signature_422068_7.pdf Trusting and Validating a Digital Siganture]|| How to trust and validate a signature in Adobe Acrobat<br />
|-<br />
|}<br />
<br />
<br />
<br />
[[Category: Construction Manual]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=719_-_Earth_Retaining_Structures&diff=3904719 - Earth Retaining Structures2014-11-14T16:01:15Z<p>HarrisR18: /* Abutments */</p>
<hr />
<div><br />
<center><span STYLE="font: 60pt arial;">'''719'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Earth Retaining Structures'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/719%20Earth%20Retaining%Structures.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 719]</center><br />
<br />
==[[#GENERAL|GENERAL]]==<br />
<br />
Below is a list with definitions of common earth retaining structures utilized by MDOT:<br />
<br />
*Abutment – A structure located at the end of a bridge span that supports the vertical loads from the bridge superstructure, and resists lateral loads from fill material on which the roadway rests immediately adjacent to the bridge.<br />
<br />
*Anchored Wall – An earth retaining system typically composed of the same elements as non-gravity cantilevered walls and that derive additional lateral resistance from one or more tiers of anchors.<br />
<br />
*Mechanically Stabilized Earth (MSE) Wall – A soil-retaining system, employing either strip or grid-type, metallic, or polymeric tensile reinforcements in the soil mass, and a facing element that is either vertical or nearly vertical.<br />
<br />
*Segmental Block Retaining Wall – A soil-retaining system, typically employing polymeric tensile reinforcements in the soil mass attached to a facing element that consists of segmental blocks. Segmental blocks are typically dry cast blocks.<br />
<br />
*Modular Block Retaining Wall – A soil-retaining system that consists of modular blocks stacked to form a gravity wall with a vertical or nearly vertical face. Modular blocks are typically large precast concrete blocks.<br />
<br />
*Non-Gravity Cantilever Retaining Wall – A soil-retaining system that derives lateral resistance through embedment of vertical wall elements and supports retained soil with facing elements. Vertical wall elements may consist of discrete elements (piles, drilled shafts, etc.) or a continuous system (sheet piles, tangent drilled shafts, etc.).<br />
<br />
*Rigid Gravity and Semi-Gravity Retaining Wall – A structure that provides lateral support for a mass of soil and that owes its stability primarily to its own weight and to the weight of any soil located directly above its base.<br />
<br />
Some of these elements may not be detailed on the plans, and may require shop drawing submittals for approval. See [[707_-_Structural_Steel#Shop_Drawing_Review_Process|707 of the MDOT Construction Manual]] for shop drawing requirements.<br />
<br />
{{top}}<br />
<br />
==[[#MATERIALS|MATERIALS]]==<br />
<span style="color: red"> -Reserved- </span><br />
<br />
{{top}}<br />
<br />
==[[#CONSTRUCTION|CONSTRUCTION]]==<br />
<br />
<br />
<br />
===[[#Abutments|Abutments]]===<br />
<br />
MDOT utilizes the following types of abutments:<br />
<br />
*Curtainwall Abutment (see rigid-gravity retaining wall below);<br />
<br />
<br />
[[File:Fig719-1.png|600px|framed|center|Figure 1. Unreinforced concrete rigid-gravity wall, or curtain wall abutment]]<br />
<br />
<br />
<br />
*Cantilevered Abutment (see semi-gravity retaining wall below)<br />
<br />
<br />
[[File:Fig719-2.png|600px|framed|center|Figure 2. reinforced cantilever abutment wall]]<br />
<br />
<br />
<br />
*Integral and Semi-Integral Abutments – Integral and semi-integral abutments are detailed in the [http://mdotcf.state.mi.us/public/design/englishbridgeguides/ MDOT Bridge Design Guides] 6.20.04, 6.20.04B, 6.20.04D.<br />
<br />
Integral abutments are designed to be supported on a single row of piles that are oriented with their webs parallel to the bridge reference line to allow weak axis bending to accommodate superstructure articulation due to thermal gradient and live loading. Splices for piles in integral abutments must be complete joint penetration (CJP). Alternative mechanical splicer channels are not permitted.<br />
<br />
{{top}}<br />
<br />
===[[#Anchored Wall| Anchored Wall]]===<br />
<br />
Anchored walls can consist of ground anchors or tie backs. Verification load testing and proof load testing of the ground anchors is typically performed on all anchors to ensure the actual lateral pullout resistance is within the design tolerances. The verification load testing procedures will be detailed in the contract documents.<br />
<br />
{{top}}<br />
<br />
===[[#Mechanically Stabilized Earth Wall| Mechanically Stabilized Earth Wall]]===<br />
<br />
Below are the basic components of a mechanically stabilized earth (MSE) wall system and a summary of items to review during construction:<br />
<br />
:A. Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed. Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.<br />
<br />
:B. Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office. <br />
<br />
:Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.<br />
<br />
:C. Wire Facing Panels – Wire facing panels are typically specified for temporary MSE walls during Stage I construction. The walls end up being buried into the final structure and are not removed. The wire facing panels in this temporary application are usually black steel due to the short duration of use.<br />
<br />
:D. Soil Reinforcement – MDOT permits the use of steel strip-type (bar or welded wire fabric ladder) reinforcement. Soil reinforcement must be placed as close to perpendicular from the wall face as practical. The reinforcement is permitted to be skewed around piling or other obstructions, but should be done so to not only reduce the skew, but also the number of skewed reinforcement strips. Reinforcement should not be in contact with other reinforcement. For skewed reinforcement soil must be placed between overlapping reinforcement. <br />
<br />
:E. Bolts – Bolts are typically positioned with the head at the bottom side of the connection lug and the washer and nut on the top side. This allows the inspector to visually inspect that the washers and nuts have been installed as the reinforced soil is constructed behind the wall. <br />
<br />
:F. Concrete Facing Panel Joint Material – Geotextile fabric is used to prevent soil particles from moving through the concrete facing panels. If the facing panel joints start to open up then the contractor should double the geotextile over the joints in question to provide additional protection.<br />
<br />
:G. Backfill for Reinforced Soil Mass – Granular soil, typically Granular Material Class II, whic is free draining and meets the required strength and electro-chemical properties. This material must be tested and approved prior to placement.<br />
<br />
:H. Leveling Pad – Is a non-reinforced concrete pad that provides a level starting point for constructing the precast concrete facing panels. A leveling pad is not needed for a wire faced MSE wall.<br />
<br />
:I. Impervious Membrane – A polyvinylchloride (PVC) liner that prevents chloride laden runoff from penetrating into the reinforced soil mass and corroding the steel reinforcement. The liner must be shingle-lapped or seam welded and is positioned to slope away from the front of the wall and extend a minimum distance beyond the end of the soil reinforcement.<br />
<br />
:J. CIP Copings – These copings are typically used as closure pours, but can also run up to 20 feet in length and can overlap adjacent panels without the need for a bond breaker. Expansion joint material is needed when butting CIP coping up to precast coping.<br />
<br />
:K. Foundation Underdrains – Are strategically placed to transport water from the reinforced soil mass to a location far away from the wall. MSE walls are generally not designed for hydrostatic pressure. Foundation underdrains are to be installed at the locations indicated on the plans. The lower foundation underdrains are to be located as low as possible but still drain to either a ditch or a drainage structure.<br />
<br />
MSE Wall Construction Considerations<br />
<br />
*During the wet cure for the concrete bridge deck the water coming off of the deck needs to be collected and discharged away from the MSE wall. Water runoff from the deck may saturate the MSE backfill and cause wall movement.<br />
<br />
*Groundwater needs to be controlled to prevent hydrostatic forces from acting on the wall. If groundwater is encountered during construction the location/number of foundation underdrains may need to be reevaluated.<br />
<br />
*Compaction of the Select Backfill and any subgrade undercuts is important in order to limit any future settlement of the MSE wall fill.<br />
<br />
[[File:Fig719-3.png|600px|framed|center|Figure 1. MSE wall]]<br />
<br />
{{top}}<br />
<br />
===[[#Non-Gravity Cantilevered Retaining Wall| Non-Gravity Cantilevered Retaining Wall]]===<br />
<br />
Examples of on-gravity cantilevered retaining walls are listed below:<br />
*Tangent piles or drilled shafts;<br />
*Drilled shafts or auger-cast piles spanned by structural facing (lagging, panels or shotcrete);<br />
*Steel sheet piling (see [[704_-_Steel_Sheet_Piling_and_Cofferdams|Section 704 – Steel Sheet Piling and Cofferdams]]).<br />
<br />
{{top}}<br />
<br />
===[[#Rigid-Gravity and Semi-Gravity Retaining Wall|Rigid-Gravity and Semi-Gravity Retaining Wall]]===<br />
<br />
[[File:Fig719-4.png|600px|framed|center|Figure 3. Reinforced concrete counterfort semi-gravity wall]]<br />
<br />
<br />
<br />
[[File:Fig719-5.png|600px|framed|center|Figure 4. Reinforced concrete cantilever semi-gravity wall.]]<br />
<br />
{{top}}<br />
<br />
==[[#MEASUREMENT AND PAYMENT|MEASUREMENT AND PAYMENT]]==<br />
<br />
<span style="color: red"> -Reserved- </span><br />
<br />
{{top}}<br />
<br />
[[Category:Construction Manual]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=719_-_Earth_Retaining_Structures&diff=3903719 - Earth Retaining Structures2014-11-14T15:02:40Z<p>HarrisR18: /* Non-Gravity Cantilevered Retaining Wall */</p>
<hr />
<div><br />
<center><span STYLE="font: 60pt arial;">'''719'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Earth Retaining Structures'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/719%20Earth%20Retaining%Structures.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 719]</center><br />
<br />
==[[#GENERAL|GENERAL]]==<br />
<br />
Below is a list with definitions of common earth retaining structures utilized by MDOT:<br />
<br />
*Abutment – A structure located at the end of a bridge span that supports the vertical loads from the bridge superstructure, and resists lateral loads from fill material on which the roadway rests immediately adjacent to the bridge.<br />
<br />
*Anchored Wall – An earth retaining system typically composed of the same elements as non-gravity cantilevered walls and that derive additional lateral resistance from one or more tiers of anchors.<br />
<br />
*Mechanically Stabilized Earth (MSE) Wall – A soil-retaining system, employing either strip or grid-type, metallic, or polymeric tensile reinforcements in the soil mass, and a facing element that is either vertical or nearly vertical.<br />
<br />
*Segmental Block Retaining Wall – A soil-retaining system, typically employing polymeric tensile reinforcements in the soil mass attached to a facing element that consists of segmental blocks. Segmental blocks are typically dry cast blocks.<br />
<br />
*Modular Block Retaining Wall – A soil-retaining system that consists of modular blocks stacked to form a gravity wall with a vertical or nearly vertical face. Modular blocks are typically large precast concrete blocks.<br />
<br />
*Non-Gravity Cantilever Retaining Wall – A soil-retaining system that derives lateral resistance through embedment of vertical wall elements and supports retained soil with facing elements. Vertical wall elements may consist of discrete elements (piles, drilled shafts, etc.) or a continuous system (sheet piles, tangent drilled shafts, etc.).<br />
<br />
*Rigid Gravity and Semi-Gravity Retaining Wall – A structure that provides lateral support for a mass of soil and that owes its stability primarily to its own weight and to the weight of any soil located directly above its base.<br />
<br />
Some of these elements may not be detailed on the plans, and may require shop drawing submittals for approval. See [[707_-_Structural_Steel#Shop_Drawing_Review_Process|707 of the MDOT Construction Manual]] for shop drawing requirements.<br />
<br />
{{top}}<br />
<br />
==[[#MATERIALS|MATERIALS]]==<br />
<span style="color: red"> -Reserved- </span><br />
<br />
{{top}}<br />
<br />
==[[#CONSTRUCTION|CONSTRUCTION]]==<br />
<br />
<br />
<br />
===[[#Abutments|Abutments]]===<br />
<br />
MDOT utilizes the following types of abutments:<br />
<br />
*Curtainwall Abutment (see rigid-gravity retaining wall below);<br />
<br />
<br />
[[File:Fig719-1.png|600px|framed|center|Figure 1. Unreinforced concrete rigid-gravity wall, or curtain wall abutment]]<br />
<br />
<br />
<br />
*Cantilevered Abutment (see semi-gravity retaining wall below)<br />
<br />
<br />
[[File:Fig719-2.png|600px|framed|center|Figure 2. reinforced cantilever abutment wall]]<br />
<br />
<br />
<br />
*Integral and Semi-Integral Abutments – Integral and semi-integral abutments are detailed in the MDOT Bridge Design Guides 6.20.04, 6.20.04B, 6.20.04D.<br />
<br />
Integral abutments are designed to be supported on a single row of piles that are oriented with their webs parallel to the bridge reference line to allow weak axis bending to accommodate superstructure articulation due to thermal gradient and live loading. Splices for piles in integral abutments must be complete joint penetration (CJP). Alternative mechanical splicer channels are not permitted.<br />
<br />
{{top}}<br />
<br />
===[[#Anchored Wall| Anchored Wall]]===<br />
<br />
Anchored walls can consist of ground anchors or tie backs. Verification load testing and proof load testing of the ground anchors is typically performed on all anchors to ensure the actual lateral pullout resistance is within the design tolerances. The verification load testing procedures will be detailed in the contract documents.<br />
<br />
{{top}}<br />
<br />
===[[#Mechanically Stabilized Earth Wall| Mechanically Stabilized Earth Wall]]===<br />
<br />
Below are the basic components of a mechanically stabilized earth (MSE) wall system and a summary of items to review during construction:<br />
<br />
:A. Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed. Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.<br />
<br />
:B. Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office. <br />
<br />
:Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.<br />
<br />
:C. Wire Facing Panels – Wire facing panels are typically specified for temporary MSE walls during Stage I construction. The walls end up being buried into the final structure and are not removed. The wire facing panels in this temporary application are usually black steel due to the short duration of use.<br />
<br />
:D. Soil Reinforcement – MDOT permits the use of steel strip-type (bar or welded wire fabric ladder) reinforcement. Soil reinforcement must be placed as close to perpendicular from the wall face as practical. The reinforcement is permitted to be skewed around piling or other obstructions, but should be done so to not only reduce the skew, but also the number of skewed reinforcement strips. Reinforcement should not be in contact with other reinforcement. For skewed reinforcement soil must be placed between overlapping reinforcement. <br />
<br />
:E. Bolts – Bolts are typically positioned with the head at the bottom side of the connection lug and the washer and nut on the top side. This allows the inspector to visually inspect that the washers and nuts have been installed as the reinforced soil is constructed behind the wall. <br />
<br />
:F. Concrete Facing Panel Joint Material – Geotextile fabric is used to prevent soil particles from moving through the concrete facing panels. If the facing panel joints start to open up then the contractor should double the geotextile over the joints in question to provide additional protection.<br />
<br />
:G. Backfill for Reinforced Soil Mass – Granular soil, typically Granular Material Class II, whic is free draining and meets the required strength and electro-chemical properties. This material must be tested and approved prior to placement.<br />
<br />
:H. Leveling Pad – Is a non-reinforced concrete pad that provides a level starting point for constructing the precast concrete facing panels. A leveling pad is not needed for a wire faced MSE wall.<br />
<br />
:I. Impervious Membrane – A polyvinylchloride (PVC) liner that prevents chloride laden runoff from penetrating into the reinforced soil mass and corroding the steel reinforcement. The liner must be shingle-lapped or seam welded and is positioned to slope away from the front of the wall and extend a minimum distance beyond the end of the soil reinforcement.<br />
<br />
:J. CIP Copings – These copings are typically used as closure pours, but can also run up to 20 feet in length and can overlap adjacent panels without the need for a bond breaker. Expansion joint material is needed when butting CIP coping up to precast coping.<br />
<br />
:K. Foundation Underdrains – Are strategically placed to transport water from the reinforced soil mass to a location far away from the wall. MSE walls are generally not designed for hydrostatic pressure. Foundation underdrains are to be installed at the locations indicated on the plans. The lower foundation underdrains are to be located as low as possible but still drain to either a ditch or a drainage structure.<br />
<br />
MSE Wall Construction Considerations<br />
<br />
*During the wet cure for the concrete bridge deck the water coming off of the deck needs to be collected and discharged away from the MSE wall. Water runoff from the deck may saturate the MSE backfill and cause wall movement.<br />
<br />
*Groundwater needs to be controlled to prevent hydrostatic forces from acting on the wall. If groundwater is encountered during construction the location/number of foundation underdrains may need to be reevaluated.<br />
<br />
*Compaction of the Select Backfill and any subgrade undercuts is important in order to limit any future settlement of the MSE wall fill.<br />
<br />
[[File:Fig719-3.png|600px|framed|center|Figure 1. MSE wall]]<br />
<br />
{{top}}<br />
<br />
===[[#Non-Gravity Cantilevered Retaining Wall| Non-Gravity Cantilevered Retaining Wall]]===<br />
<br />
Examples of on-gravity cantilevered retaining walls are listed below:<br />
*Tangent piles or drilled shafts;<br />
*Drilled shafts or auger-cast piles spanned by structural facing (lagging, panels or shotcrete);<br />
*Steel sheet piling (see [[704_-_Steel_Sheet_Piling_and_Cofferdams|Section 704 – Steel Sheet Piling and Cofferdams]]).<br />
<br />
{{top}}<br />
<br />
===[[#Rigid-Gravity and Semi-Gravity Retaining Wall|Rigid-Gravity and Semi-Gravity Retaining Wall]]===<br />
<br />
[[File:Fig719-4.png|600px|framed|center|Figure 3. Reinforced concrete counterfort semi-gravity wall]]<br />
<br />
<br />
<br />
[[File:Fig719-5.png|600px|framed|center|Figure 4. Reinforced concrete cantilever semi-gravity wall.]]<br />
<br />
{{top}}<br />
<br />
==[[#MEASUREMENT AND PAYMENT|MEASUREMENT AND PAYMENT]]==<br />
<br />
<span style="color: red"> -Reserved- </span><br />
<br />
{{top}}<br />
<br />
[[Category:Construction Manual]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=719_-_Earth_Retaining_Structures&diff=3899719 - Earth Retaining Structures2014-11-14T14:46:17Z<p>HarrisR18: </p>
<hr />
<div><br />
<center><span STYLE="font: 60pt arial;">'''719'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Earth Retaining Structures'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/719%20Earth%20Retaining%Structures.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 719]</center><br />
<br />
==[[#GENERAL|GENERAL]]==<br />
<br />
Below is a list with definitions of common earth retaining structures utilized by MDOT:<br />
<br />
*Abutment – A structure located at the end of a bridge span that supports the vertical loads from the bridge superstructure, and resists lateral loads from fill material on which the roadway rests immediately adjacent to the bridge.<br />
<br />
*Anchored Wall – An earth retaining system typically composed of the same elements as non-gravity cantilevered walls and that derive additional lateral resistance from one or more tiers of anchors.<br />
<br />
*Mechanically Stabilized Earth (MSE) Wall – A soil-retaining system, employing either strip or grid-type, metallic, or polymeric tensile reinforcements in the soil mass, and a facing element that is either vertical or nearly vertical.<br />
<br />
*Segmental Block Retaining Wall – A soil-retaining system, typically employing polymeric tensile reinforcements in the soil mass attached to a facing element that consists of segmental blocks. Segmental blocks are typically dry cast blocks.<br />
<br />
*Modular Block Retaining Wall – A soil-retaining system that consists of modular blocks stacked to form a gravity wall with a vertical or nearly vertical face. Modular blocks are typically large precast concrete blocks.<br />
<br />
*Non-Gravity Cantilever Retaining Wall – A soil-retaining system that derives lateral resistance through embedment of vertical wall elements and supports retained soil with facing elements. Vertical wall elements may consist of discrete elements (piles, drilled shafts, etc.) or a continuous system (sheet piles, tangent drilled shafts, etc.).<br />
<br />
*Rigid Gravity and Semi-Gravity Retaining Wall – A structure that provides lateral support for a mass of soil and that owes its stability primarily to its own weight and to the weight of any soil located directly above its base.<br />
<br />
Some of these elements may not be detailed on the plans, and may require shop drawing submittals for approval. See 707 of the MDOT Construction Manual for shop drawing requirements.<br />
<br />
{{top}}<br />
<br />
==[[#MATERIALS|MATERIALS]]==<br />
<span style="color: red"> -Reserved- </span><br />
<br />
{{top}}<br />
<br />
==[[#CONSTRUCTION|CONSTRUCTION]]==<br />
<br />
<br />
<br />
===[[#Abutments|Abutments]]===<br />
<br />
MDOT utilizes the following types of abutments:<br />
<br />
*Curtainwall Abutment (see rigid-gravity retaining wall below);<br />
<br />
<br />
[[File:Fig719-1.png|600px|framed|center|Figure 1. Unreinforced concrete rigid-gravity wall, or curtain wall abutment]]<br />
<br />
<br />
<br />
*Cantilevered Abutment (see semi-gravity retaining wall below)<br />
<br />
<br />
[[File:Fig719-2.png|600px|framed|center|Figure 2. reinforced cantilever abutment wall]]<br />
<br />
<br />
<br />
*Integral and Semi-Integral Abutments – Integral and semi-integral abutments are detailed in the MDOT Bridge Design Guides 6.20.04, 6.20.04B, 6.20.04D.<br />
<br />
Integral abutments are designed to be supported on a single row of piles that are oriented with their webs parallel to the bridge reference line to allow weak axis bending to accommodate superstructure articulation due to thermal gradient and live loading. Splices for piles in integral abutments must be complete joint penetration (CJP). Alternative mechanical splicer channels are not permitted.<br />
<br />
{{top}}<br />
<br />
===[[#Anchored Wall| Anchored Wall]]===<br />
<br />
Anchored walls can consist of ground anchors or tie backs. Verification load testing and proof load testing of the ground anchors is typically performed on all anchors to ensure the actual lateral pullout resistance is within the design tolerances. The verification load testing procedures will be detailed in the contract documents.<br />
<br />
{{top}}<br />
<br />
===[[#Mechanically Stabilized Earth Wall| Mechanically Stabilized Earth Wall]]===<br />
<br />
Below are the basic components of a mechanically stabilized earth (MSE) wall system and a summary of items to review during construction:<br />
<br />
:A. Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed. Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.<br />
<br />
:B. Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office. <br />
<br />
:Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.<br />
<br />
:C. Wire Facing Panels – Wire facing panels are typically specified for temporary MSE walls during Stage I construction. The walls end up being buried into the final structure and are not removed. The wire facing panels in this temporary application are usually black steel due to the short duration of use.<br />
<br />
:D. Soil Reinforcement – MDOT permits the use of steel strip-type (bar or welded wire fabric ladder) reinforcement. Soil reinforcement must be placed as close to perpendicular from the wall face as practical. The reinforcement is permitted to be skewed around piling or other obstructions, but should be done so to not only reduce the skew, but also the number of skewed reinforcement strips. Reinforcement should not be in contact with other reinforcement. For skewed reinforcement soil must be placed between overlapping reinforcement. <br />
<br />
:E. Bolts – Bolts are typically positioned with the head at the bottom side of the connection lug and the washer and nut on the top side. This allows the inspector to visually inspect that the washers and nuts have been installed as the reinforced soil is constructed behind the wall. <br />
<br />
:F. Concrete Facing Panel Joint Material – Geotextile fabric is used to prevent soil particles from moving through the concrete facing panels. If the facing panel joints start to open up then the contractor should double the geotextile over the joints in question to provide additional protection.<br />
<br />
:G. Backfill for Reinforced Soil Mass – Granular soil, typically Granular Material Class II, whic is free draining and meets the required strength and electro-chemical properties. This material must be tested and approved prior to placement.<br />
<br />
:H. Leveling Pad – Is a non-reinforced concrete pad that provides a level starting point for constructing the precast concrete facing panels. A leveling pad is not needed for a wire faced MSE wall.<br />
<br />
:I. Impervious Membrane – A polyvinylchloride (PVC) liner that prevents chloride laden runoff from penetrating into the reinforced soil mass and corroding the steel reinforcement. The liner must be shingle-lapped or seam welded and is positioned to slope away from the front of the wall and extend a minimum distance beyond the end of the soil reinforcement.<br />
<br />
:J. CIP Copings – These copings are typically used as closure pours, but can also run up to 20 feet in length and can overlap adjacent panels without the need for a bond breaker. Expansion joint material is needed when butting CIP coping up to precast coping.<br />
<br />
:K. Foundation Underdrains – Are strategically placed to transport water from the reinforced soil mass to a location far away from the wall. MSE walls are generally not designed for hydrostatic pressure. Foundation underdrains are to be installed at the locations indicated on the plans. The lower foundation underdrains are to be located as low as possible but still drain to either a ditch or a drainage structure.<br />
<br />
MSE Wall Construction Considerations<br />
<br />
*During the wet cure for the concrete bridge deck the water coming off of the deck needs to be collected and discharged away from the MSE wall. Water runoff from the deck may saturate the MSE backfill and cause wall movement.<br />
<br />
*Groundwater needs to be controlled to prevent hydrostatic forces from acting on the wall. If groundwater is encountered during construction the location/number of foundation underdrains may need to be reevaluated.<br />
<br />
*Compaction of the Select Backfill and any subgrade undercuts is important in order to limit any future settlement of the MSE wall fill.<br />
<br />
[[File:Fig719-3.png|600px|framed|center|Figure 1. MSE wall]]<br />
<br />
{{top}}<br />
<br />
===[[#Non-Gravity Cantilevered Retaining Wall| Non-Gravity Cantilevered Retaining Wall]]===<br />
<br />
Examples of on-gravity cantilevered retaining walls are listed below:<br />
*Tangent piles or drilled shafts;<br />
*Drilled shafts or auger-cast piles spanned by structural facing (lagging, panels or shotcrete);<br />
*Steel sheet piling (see Section 704 – Steel Sheet Piling and Cofferdams).<br />
<br />
{{top}}<br />
<br />
===[[#Rigid-Gravity and Semi-Gravity Retaining Wall|Rigid-Gravity and Semi-Gravity Retaining Wall]]===<br />
<br />
[[File:Fig719-4.png|600px|framed|center|Figure 3. Reinforced concrete counterfort semi-gravity wall]]<br />
<br />
<br />
<br />
[[File:Fig719-5.png|600px|framed|center|Figure 4. Reinforced concrete cantilever semi-gravity wall.]]<br />
<br />
{{top}}<br />
<br />
==[[#MEASUREMENT AND PAYMENT|MEASUREMENT AND PAYMENT]]==<br />
<br />
<span style="color: red"> -Reserved- </span><br />
<br />
{{top}}</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=719_-_Earth_Retaining_Structures&diff=3898719 - Earth Retaining Structures2014-11-14T14:45:26Z<p>HarrisR18: </p>
<hr />
<div><br />
<center><span STYLE="font: 60pt arial;">'''719'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Earth Retaining Structures'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/719%20Earth%20Retaining%Structures.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 719]</center><br />
<br />
==[[#GENERAL|GENERAL]]==<br />
<br />
Below is a list with definitions of common earth retaining structures utilized by MDOT:<br />
<br />
*Abutment – A structure located at the end of a bridge span that supports the vertical loads from the bridge superstructure, and resists lateral loads from fill material on which the roadway rests immediately adjacent to the bridge.<br />
<br />
*Anchored Wall – An earth retaining system typically composed of the same elements as non-gravity cantilevered walls and that derive additional lateral resistance from one or more tiers of anchors.<br />
<br />
*Mechanically Stabilized Earth (MSE) Wall – A soil-retaining system, employing either strip or grid-type, metallic, or polymeric tensile reinforcements in the soil mass, and a facing element that is either vertical or nearly vertical.<br />
<br />
*Segmental Block Retaining Wall – A soil-retaining system, typically employing polymeric tensile reinforcements in the soil mass attached to a facing element that consists of segmental blocks. Segmental blocks are typically dry cast blocks.<br />
<br />
*Modular Block Retaining Wall – A soil-retaining system that consists of modular blocks stacked to form a gravity wall with a vertical or nearly vertical face. Modular blocks are typically large precast concrete blocks.<br />
<br />
*Non-Gravity Cantilever Retaining Wall – A soil-retaining system that derives lateral resistance through embedment of vertical wall elements and supports retained soil with facing elements. Vertical wall elements may consist of discrete elements (piles, drilled shafts, etc.) or a continuous system (sheet piles, tangent drilled shafts, etc.).<br />
<br />
*Rigid Gravity and Semi-Gravity Retaining Wall – A structure that provides lateral support for a mass of soil and that owes its stability primarily to its own weight and to the weight of any soil located directly above its base.<br />
<br />
Some of these elements may not be detailed on the plans, and may require shop drawing submittals for approval. See 707 of the MDOT Construction Manual for shop drawing requirements.<br />
<br />
{{top}}<br />
<br />
==[[#MATERIALS|MATERIALS]]==<br />
<span style="color: red"> -Reserved- </span><br />
<br />
{{top}}<br />
<br />
==[[#Construction|Construction]]==<br />
<br />
<br />
<br />
===[[#Abutments|Abutments]]===<br />
<br />
MDOT utilizes the following types of abutments:<br />
<br />
*Curtainwall Abutment (see rigid-gravity retaining wall below);<br />
<br />
<br />
[[File:Fig719-1.png|600px|framed|center|Figure 1. Unreinforced concrete rigid-gravity wall, or curtain wall abutment]]<br />
<br />
<br />
<br />
*Cantilevered Abutment (see semi-gravity retaining wall below)<br />
<br />
<br />
[[File:Fig719-2.png|600px|framed|center|Figure 2. reinforced cantilever abutment wall]]<br />
<br />
<br />
<br />
*Integral and Semi-Integral Abutments – Integral and semi-integral abutments are detailed in the MDOT Bridge Design Guides 6.20.04, 6.20.04B, 6.20.04D.<br />
<br />
Integral abutments are designed to be supported on a single row of piles that are oriented with their webs parallel to the bridge reference line to allow weak axis bending to accommodate superstructure articulation due to thermal gradient and live loading. Splices for piles in integral abutments must be complete joint penetration (CJP). Alternative mechanical splicer channels are not permitted.<br />
<br />
{{top}}<br />
<br />
===[[#Anchored Wall| Anchored Wall]]===<br />
<br />
Anchored walls can consist of ground anchors or tie backs. Verification load testing and proof load testing of the ground anchors is typically performed on all anchors to ensure the actual lateral pullout resistance is within the design tolerances. The verification load testing procedures will be detailed in the contract documents.<br />
<br />
{{top}}<br />
<br />
===[[#Mechanically Stabilized Earth Wall| Mechanically Stabilized Earth Wall]]===<br />
<br />
Below are the basic components of a mechanically stabilized earth (MSE) wall system and a summary of items to review during construction:<br />
<br />
:A. Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed. Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.<br />
<br />
:B. Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office. <br />
<br />
:Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.<br />
<br />
:C. Wire Facing Panels – Wire facing panels are typically specified for temporary MSE walls during Stage I construction. The walls end up being buried into the final structure and are not removed. The wire facing panels in this temporary application are usually black steel due to the short duration of use.<br />
<br />
:D. Soil Reinforcement – MDOT permits the use of steel strip-type (bar or welded wire fabric ladder) reinforcement. Soil reinforcement must be placed as close to perpendicular from the wall face as practical. The reinforcement is permitted to be skewed around piling or other obstructions, but should be done so to not only reduce the skew, but also the number of skewed reinforcement strips. Reinforcement should not be in contact with other reinforcement. For skewed reinforcement soil must be placed between overlapping reinforcement. <br />
<br />
:E. Bolts – Bolts are typically positioned with the head at the bottom side of the connection lug and the washer and nut on the top side. This allows the inspector to visually inspect that the washers and nuts have been installed as the reinforced soil is constructed behind the wall. <br />
<br />
:F. Concrete Facing Panel Joint Material – Geotextile fabric is used to prevent soil particles from moving through the concrete facing panels. If the facing panel joints start to open up then the contractor should double the geotextile over the joints in question to provide additional protection.<br />
<br />
:G. Backfill for Reinforced Soil Mass – Granular soil, typically Granular Material Class II, whic is free draining and meets the required strength and electro-chemical properties. This material must be tested and approved prior to placement.<br />
<br />
:H. Leveling Pad – Is a non-reinforced concrete pad that provides a level starting point for constructing the precast concrete facing panels. A leveling pad is not needed for a wire faced MSE wall.<br />
<br />
:I. Impervious Membrane – A polyvinylchloride (PVC) liner that prevents chloride laden runoff from penetrating into the reinforced soil mass and corroding the steel reinforcement. The liner must be shingle-lapped or seam welded and is positioned to slope away from the front of the wall and extend a minimum distance beyond the end of the soil reinforcement.<br />
<br />
:J. CIP Copings – These copings are typically used as closure pours, but can also run up to 20 feet in length and can overlap adjacent panels without the need for a bond breaker. Expansion joint material is needed when butting CIP coping up to precast coping.<br />
<br />
:K. Foundation Underdrains – Are strategically placed to transport water from the reinforced soil mass to a location far away from the wall. MSE walls are generally not designed for hydrostatic pressure. Foundation underdrains are to be installed at the locations indicated on the plans. The lower foundation underdrains are to be located as low as possible but still drain to either a ditch or a drainage structure.<br />
<br />
MSE Wall Construction Considerations<br />
<br />
*During the wet cure for the concrete bridge deck the water coming off of the deck needs to be collected and discharged away from the MSE wall. Water runoff from the deck may saturate the MSE backfill and cause wall movement.<br />
<br />
*Groundwater needs to be controlled to prevent hydrostatic forces from acting on the wall. If groundwater is encountered during construction the location/number of foundation underdrains may need to be reevaluated.<br />
<br />
*Compaction of the Select Backfill and any subgrade undercuts is important in order to limit any future settlement of the MSE wall fill.<br />
<br />
[[File:Fig719-3.png|600px|framed|center|Figure 1. MSE wall]]<br />
<br />
{{top}}<br />
<br />
===[[#Non-Gravity Cantilevered Retaining Wall| Non-Gravity Cantilevered Retaining Wall]]===<br />
<br />
Examples of on-gravity cantilevered retaining walls are listed below:<br />
*Tangent piles or drilled shafts;<br />
*Drilled shafts or auger-cast piles spanned by structural facing (lagging, panels or shotcrete);<br />
*Steel sheet piling (see Section 704 – Steel Sheet Piling and Cofferdams).<br />
<br />
{{top}}<br />
<br />
===[[#Rigid-Gravity and Semi-Gravity Retaining Wall|Rigid-Gravity and Semi-Gravity Retaining Wall]]===<br />
<br />
[[File:Fig719-4.png|600px|framed|center|Figure 3. Reinforced concrete counterfort semi-gravity wall]]<br />
<br />
<br />
<br />
[[File:Fig719-5.png|600px|framed|center|Figure 4. Reinforced concrete cantilever semi-gravity wall.]]<br />
<br />
{{top}}<br />
<br />
==[[#MEASUREMENT AND PAYMENT|MEASUREMENT AND PAYMENT]]==<br />
<br />
<span style="color: red"> -Reserved- </span><br />
<br />
{{top}}</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=719_-_Earth_Retaining_Structures&diff=3897719 - Earth Retaining Structures2014-11-14T14:40:35Z<p>HarrisR18: /* Measurement and Payment */</p>
<hr />
<div><br />
<center><span STYLE="font: 60pt arial;">'''719'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Earth Retaining Structures'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/719%20Earth%20Retaining%Structures.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 719]</center><br />
<br />
==[[#General|General]]==<br />
<br />
Below is a list with definitions of common earth retaining structures utilized by MDOT:<br />
<br />
*Abutment – A structure located at the end of a bridge span that supports the vertical loads from the bridge superstructure, and resists lateral loads from fill material on which the roadway rests immediately adjacent to the bridge.<br />
<br />
*Anchored Wall – An earth retaining system typically composed of the same elements as non-gravity cantilevered walls and that derive additional lateral resistance from one or more tiers of anchors.<br />
<br />
*Mechanically Stabilized Earth (MSE) Wall – A soil-retaining system, employing either strip or grid-type, metallic, or polymeric tensile reinforcements in the soil mass, and a facing element that is either vertical or nearly vertical.<br />
<br />
*Segmental Block Retaining Wall – A soil-retaining system, typically employing polymeric tensile reinforcements in the soil mass attached to a facing element that consists of segmental blocks. Segmental blocks are typically dry cast blocks.<br />
<br />
*Modular Block Retaining Wall – A soil-retaining system that consists of modular blocks stacked to form a gravity wall with a vertical or nearly vertical face. Modular blocks are typically large precast concrete blocks.<br />
<br />
*Non-Gravity Cantilever Retaining Wall – A soil-retaining system that derives lateral resistance through embedment of vertical wall elements and supports retained soil with facing elements. Vertical wall elements may consist of discrete elements (piles, drilled shafts, etc.) or a continuous system (sheet piles, tangent drilled shafts, etc.).<br />
<br />
*Rigid Gravity and Semi-Gravity Retaining Wall – A structure that provides lateral support for a mass of soil and that owes its stability primarily to its own weight and to the weight of any soil located directly above its base.<br />
<br />
Some of these elements may not be detailed on the plans, and may require shop drawing submittals for approval. See 707 of the MDOT Construction Manual for shop drawing requirements.<br />
<br />
{{top}}<br />
<br />
==[[#Materials|Materials]]==<br />
<span style="color: red"> -Reserved- </span><br />
<br />
{{top}}<br />
<br />
==[[#Construction|Construction]]==<br />
<br />
<br />
<br />
===[[#Abutments|Abutments]]===<br />
<br />
MDOT utilizes the following types of abutments:<br />
<br />
*Curtainwall Abutment (see rigid-gravity retaining wall below);<br />
<br />
<br />
[[File:Fig719-1.png|600px|framed|center|Figure 1. Unreinforced concrete rigid-gravity wall, or curtain wall abutment]]<br />
<br />
<br />
<br />
*Cantilevered Abutment (see semi-gravity retaining wall below)<br />
<br />
<br />
[[File:Fig719-2.png|600px|framed|center|Figure 2. reinforced cantilever abutment wall]]<br />
<br />
<br />
<br />
*Integral and Semi-Integral Abutments – Integral and semi-integral abutments are detailed in the MDOT Bridge Design Guides 6.20.04, 6.20.04B, 6.20.04D.<br />
<br />
Integral abutments are designed to be supported on a single row of piles that are oriented with their webs parallel to the bridge reference line to allow weak axis bending to accommodate superstructure articulation due to thermal gradient and live loading. Splices for piles in integral abutments must be complete joint penetration (CJP). Alternative mechanical splicer channels are not permitted.<br />
<br />
{{top}}<br />
<br />
===[[#Anchored Wall|Anchored Wall]]===<br />
<br />
Anchored walls can consist of ground anchors or tie backs. Verification load testing and proof load testing of the ground anchors is typically performed on all anchors to ensure the actual lateral pullout resistance is within the design tolerances. The verification load testing procedures will be detailed in the contract documents.<br />
<br />
{{top}}<br />
<br />
===[[#Mechanically Stabilized Earth Wall| Mechanically Stabilized Earth Wall]]===<br />
<br />
Below are the basic components of a mechanically stabilized earth (MSE) wall system and a summary of items to review during construction:<br />
<br />
:A. Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed. Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.<br />
<br />
:B. Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office. <br />
<br />
:Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.<br />
<br />
:C. Wire Facing Panels – Wire facing panels are typically specified for temporary MSE walls during Stage I construction. The walls end up being buried into the final structure and are not removed. The wire facing panels in this temporary application are usually black steel due to the short duration of use.<br />
<br />
:D. Soil Reinforcement – MDOT permits the use of steel strip-type (bar or welded wire fabric ladder) reinforcement. Soil reinforcement must be placed as close to perpendicular from the wall face as practical. The reinforcement is permitted to be skewed around piling or other obstructions, but should be done so to not only reduce the skew, but also the number of skewed reinforcement strips. Reinforcement should not be in contact with other reinforcement. For skewed reinforcement soil must be placed between overlapping reinforcement. <br />
<br />
:E. Bolts – Bolts are typically positioned with the head at the bottom side of the connection lug and the washer and nut on the top side. This allows the inspector to visually inspect that the washers and nuts have been installed as the reinforced soil is constructed behind the wall. <br />
<br />
:F. Concrete Facing Panel Joint Material – Geotextile fabric is used to prevent soil particles from moving through the concrete facing panels. If the facing panel joints start to open up then the contractor should double the geotextile over the joints in question to provide additional protection.<br />
<br />
:G. Backfill for Reinforced Soil Mass – Granular soil, typically Granular Material Class II, whic is free draining and meets the required strength and electro-chemical properties. This material must be tested and approved prior to placement.<br />
<br />
:H. Leveling Pad – Is a non-reinforced concrete pad that provides a level starting point for constructing the precast concrete facing panels. A leveling pad is not needed for a wire faced MSE wall.<br />
<br />
:I. Impervious Membrane – A polyvinylchloride (PVC) liner that prevents chloride laden runoff from penetrating into the reinforced soil mass and corroding the steel reinforcement. The liner must be shingle-lapped or seam welded and is positioned to slope away from the front of the wall and extend a minimum distance beyond the end of the soil reinforcement.<br />
<br />
:J. CIP Copings – These copings are typically used as closure pours, but can also run up to 20 feet in length and can overlap adjacent panels without the need for a bond breaker. Expansion joint material is needed when butting CIP coping up to precast coping.<br />
<br />
:K. Foundation Underdrains – Are strategically placed to transport water from the reinforced soil mass to a location far away from the wall. MSE walls are generally not designed for hydrostatic pressure. Foundation underdrains are to be installed at the locations indicated on the plans. The lower foundation underdrains are to be located as low as possible but still drain to either a ditch or a drainage structure.<br />
<br />
MSE Wall Construction Considerations<br />
<br />
*During the wet cure for the concrete bridge deck the water coming off of the deck needs to be collected and discharged away from the MSE wall. Water runoff from the deck may saturate the MSE backfill and cause wall movement.<br />
<br />
*Groundwater needs to be controlled to prevent hydrostatic forces from acting on the wall. If groundwater is encountered during construction the location/number of foundation underdrains may need to be reevaluated.<br />
<br />
*Compaction of the Select Backfill and any subgrade undercuts is important in order to limit any future settlement of the MSE wall fill.<br />
<br />
[[File:Fig719-3.png|600px|framed|center|Figure 1. MSE wall]]<br />
<br />
{{top}}<br />
<br />
===[[#Non-Gravity Cantilevered Retaining Wall| Non-Gravity Cantilevered Retaining Wall]]===<br />
<br />
Examples of on-gravity cantilevered retaining walls are listed below:<br />
*Tangent piles or drilled shafts;<br />
*Drilled shafts or auger-cast piles spanned by structural facing (lagging, panels or shotcrete);<br />
*Steel sheet piling (see Section 704 – Steel Sheet Piling and Cofferdams).<br />
<br />
{{top}}<br />
<br />
===[[#Rigid-Gravity and Semi-Gravity Retaining Wall|Rigid-Gravity and Semi-Gravity Retaining Wall]]===<br />
<br />
[[File:Fig719-4.png|600px|framed|center|Figure 3. Reinforced concrete counterfort semi-gravity wall]]<br />
<br />
<br />
<br />
[[File:Fig719-5.png|600px|framed|center|Figure 4. Reinforced concrete cantilever semi-gravity wall.]]<br />
<br />
{{top}}<br />
<br />
==[[#Measurement and Payment|Measurement and Payment]]==<br />
<br />
<span style="color: red"> -Reserved- </span><br />
<br />
{{top}}</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=719_-_Earth_Retaining_Structures&diff=3896719 - Earth Retaining Structures2014-11-14T14:39:34Z<p>HarrisR18: /* Materials */</p>
<hr />
<div><br />
<center><span STYLE="font: 60pt arial;">'''719'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Earth Retaining Structures'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/719%20Earth%20Retaining%Structures.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 719]</center><br />
<br />
==[[#General|General]]==<br />
<br />
Below is a list with definitions of common earth retaining structures utilized by MDOT:<br />
<br />
*Abutment – A structure located at the end of a bridge span that supports the vertical loads from the bridge superstructure, and resists lateral loads from fill material on which the roadway rests immediately adjacent to the bridge.<br />
<br />
*Anchored Wall – An earth retaining system typically composed of the same elements as non-gravity cantilevered walls and that derive additional lateral resistance from one or more tiers of anchors.<br />
<br />
*Mechanically Stabilized Earth (MSE) Wall – A soil-retaining system, employing either strip or grid-type, metallic, or polymeric tensile reinforcements in the soil mass, and a facing element that is either vertical or nearly vertical.<br />
<br />
*Segmental Block Retaining Wall – A soil-retaining system, typically employing polymeric tensile reinforcements in the soil mass attached to a facing element that consists of segmental blocks. Segmental blocks are typically dry cast blocks.<br />
<br />
*Modular Block Retaining Wall – A soil-retaining system that consists of modular blocks stacked to form a gravity wall with a vertical or nearly vertical face. Modular blocks are typically large precast concrete blocks.<br />
<br />
*Non-Gravity Cantilever Retaining Wall – A soil-retaining system that derives lateral resistance through embedment of vertical wall elements and supports retained soil with facing elements. Vertical wall elements may consist of discrete elements (piles, drilled shafts, etc.) or a continuous system (sheet piles, tangent drilled shafts, etc.).<br />
<br />
*Rigid Gravity and Semi-Gravity Retaining Wall – A structure that provides lateral support for a mass of soil and that owes its stability primarily to its own weight and to the weight of any soil located directly above its base.<br />
<br />
Some of these elements may not be detailed on the plans, and may require shop drawing submittals for approval. See 707 of the MDOT Construction Manual for shop drawing requirements.<br />
<br />
{{top}}<br />
<br />
==[[#Materials|Materials]]==<br />
<span style="color: red"> -Reserved- </span><br />
<br />
{{top}}<br />
<br />
==[[#Construction|Construction]]==<br />
<br />
<br />
<br />
===[[#Abutments|Abutments]]===<br />
<br />
MDOT utilizes the following types of abutments:<br />
<br />
*Curtainwall Abutment (see rigid-gravity retaining wall below);<br />
<br />
<br />
[[File:Fig719-1.png|600px|framed|center|Figure 1. Unreinforced concrete rigid-gravity wall, or curtain wall abutment]]<br />
<br />
<br />
<br />
*Cantilevered Abutment (see semi-gravity retaining wall below)<br />
<br />
<br />
[[File:Fig719-2.png|600px|framed|center|Figure 2. reinforced cantilever abutment wall]]<br />
<br />
<br />
<br />
*Integral and Semi-Integral Abutments – Integral and semi-integral abutments are detailed in the MDOT Bridge Design Guides 6.20.04, 6.20.04B, 6.20.04D.<br />
<br />
Integral abutments are designed to be supported on a single row of piles that are oriented with their webs parallel to the bridge reference line to allow weak axis bending to accommodate superstructure articulation due to thermal gradient and live loading. Splices for piles in integral abutments must be complete joint penetration (CJP). Alternative mechanical splicer channels are not permitted.<br />
<br />
{{top}}<br />
<br />
===[[#Anchored Wall|Anchored Wall]]===<br />
<br />
Anchored walls can consist of ground anchors or tie backs. Verification load testing and proof load testing of the ground anchors is typically performed on all anchors to ensure the actual lateral pullout resistance is within the design tolerances. The verification load testing procedures will be detailed in the contract documents.<br />
<br />
{{top}}<br />
<br />
===[[#Mechanically Stabilized Earth Wall| Mechanically Stabilized Earth Wall]]===<br />
<br />
Below are the basic components of a mechanically stabilized earth (MSE) wall system and a summary of items to review during construction:<br />
<br />
:A. Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed. Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.<br />
<br />
:B. Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office. <br />
<br />
:Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.<br />
<br />
:C. Wire Facing Panels – Wire facing panels are typically specified for temporary MSE walls during Stage I construction. The walls end up being buried into the final structure and are not removed. The wire facing panels in this temporary application are usually black steel due to the short duration of use.<br />
<br />
:D. Soil Reinforcement – MDOT permits the use of steel strip-type (bar or welded wire fabric ladder) reinforcement. Soil reinforcement must be placed as close to perpendicular from the wall face as practical. The reinforcement is permitted to be skewed around piling or other obstructions, but should be done so to not only reduce the skew, but also the number of skewed reinforcement strips. Reinforcement should not be in contact with other reinforcement. For skewed reinforcement soil must be placed between overlapping reinforcement. <br />
<br />
:E. Bolts – Bolts are typically positioned with the head at the bottom side of the connection lug and the washer and nut on the top side. This allows the inspector to visually inspect that the washers and nuts have been installed as the reinforced soil is constructed behind the wall. <br />
<br />
:F. Concrete Facing Panel Joint Material – Geotextile fabric is used to prevent soil particles from moving through the concrete facing panels. If the facing panel joints start to open up then the contractor should double the geotextile over the joints in question to provide additional protection.<br />
<br />
:G. Backfill for Reinforced Soil Mass – Granular soil, typically Granular Material Class II, whic is free draining and meets the required strength and electro-chemical properties. This material must be tested and approved prior to placement.<br />
<br />
:H. Leveling Pad – Is a non-reinforced concrete pad that provides a level starting point for constructing the precast concrete facing panels. A leveling pad is not needed for a wire faced MSE wall.<br />
<br />
:I. Impervious Membrane – A polyvinylchloride (PVC) liner that prevents chloride laden runoff from penetrating into the reinforced soil mass and corroding the steel reinforcement. The liner must be shingle-lapped or seam welded and is positioned to slope away from the front of the wall and extend a minimum distance beyond the end of the soil reinforcement.<br />
<br />
:J. CIP Copings – These copings are typically used as closure pours, but can also run up to 20 feet in length and can overlap adjacent panels without the need for a bond breaker. Expansion joint material is needed when butting CIP coping up to precast coping.<br />
<br />
:K. Foundation Underdrains – Are strategically placed to transport water from the reinforced soil mass to a location far away from the wall. MSE walls are generally not designed for hydrostatic pressure. Foundation underdrains are to be installed at the locations indicated on the plans. The lower foundation underdrains are to be located as low as possible but still drain to either a ditch or a drainage structure.<br />
<br />
MSE Wall Construction Considerations<br />
<br />
*During the wet cure for the concrete bridge deck the water coming off of the deck needs to be collected and discharged away from the MSE wall. Water runoff from the deck may saturate the MSE backfill and cause wall movement.<br />
<br />
*Groundwater needs to be controlled to prevent hydrostatic forces from acting on the wall. If groundwater is encountered during construction the location/number of foundation underdrains may need to be reevaluated.<br />
<br />
*Compaction of the Select Backfill and any subgrade undercuts is important in order to limit any future settlement of the MSE wall fill.<br />
<br />
[[File:Fig719-3.png|600px|framed|center|Figure 1. MSE wall]]<br />
<br />
{{top}}<br />
<br />
===[[#Non-Gravity Cantilevered Retaining Wall| Non-Gravity Cantilevered Retaining Wall]]===<br />
<br />
Examples of on-gravity cantilevered retaining walls are listed below:<br />
*Tangent piles or drilled shafts;<br />
*Drilled shafts or auger-cast piles spanned by structural facing (lagging, panels or shotcrete);<br />
*Steel sheet piling (see Section 704 – Steel Sheet Piling and Cofferdams).<br />
<br />
{{top}}<br />
<br />
===[[#Rigid-Gravity and Semi-Gravity Retaining Wall|Rigid-Gravity and Semi-Gravity Retaining Wall]]===<br />
<br />
[[File:Fig719-4.png|600px|framed|center|Figure 3. Reinforced concrete counterfort semi-gravity wall]]<br />
<br />
<br />
<br />
[[File:Fig719-5.png|600px|framed|center|Figure 4. Reinforced concrete cantilever semi-gravity wall.]]<br />
<br />
{{top}}<br />
<br />
==[[#Measurement and Payment|Measurement and Payment]]==<br />
<br />
{{top}}</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=719_-_Earth_Retaining_Structures&diff=3895719 - Earth Retaining Structures2014-11-14T14:38:24Z<p>HarrisR18: </p>
<hr />
<div><br />
<center><span STYLE="font: 60pt arial;">'''719'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Earth Retaining Structures'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/719%20Earth%20Retaining%Structures.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 719]</center><br />
<br />
==[[#General|General]]==<br />
<br />
Below is a list with definitions of common earth retaining structures utilized by MDOT:<br />
<br />
*Abutment – A structure located at the end of a bridge span that supports the vertical loads from the bridge superstructure, and resists lateral loads from fill material on which the roadway rests immediately adjacent to the bridge.<br />
<br />
*Anchored Wall – An earth retaining system typically composed of the same elements as non-gravity cantilevered walls and that derive additional lateral resistance from one or more tiers of anchors.<br />
<br />
*Mechanically Stabilized Earth (MSE) Wall – A soil-retaining system, employing either strip or grid-type, metallic, or polymeric tensile reinforcements in the soil mass, and a facing element that is either vertical or nearly vertical.<br />
<br />
*Segmental Block Retaining Wall – A soil-retaining system, typically employing polymeric tensile reinforcements in the soil mass attached to a facing element that consists of segmental blocks. Segmental blocks are typically dry cast blocks.<br />
<br />
*Modular Block Retaining Wall – A soil-retaining system that consists of modular blocks stacked to form a gravity wall with a vertical or nearly vertical face. Modular blocks are typically large precast concrete blocks.<br />
<br />
*Non-Gravity Cantilever Retaining Wall – A soil-retaining system that derives lateral resistance through embedment of vertical wall elements and supports retained soil with facing elements. Vertical wall elements may consist of discrete elements (piles, drilled shafts, etc.) or a continuous system (sheet piles, tangent drilled shafts, etc.).<br />
<br />
*Rigid Gravity and Semi-Gravity Retaining Wall – A structure that provides lateral support for a mass of soil and that owes its stability primarily to its own weight and to the weight of any soil located directly above its base.<br />
<br />
Some of these elements may not be detailed on the plans, and may require shop drawing submittals for approval. See 707 of the MDOT Construction Manual for shop drawing requirements.<br />
<br />
{{top}}<br />
<br />
==[[#Materials|Materials]]==<br />
<br />
{{top}}<br />
<br />
<br />
==[[#Construction|Construction]]==<br />
<br />
<br />
<br />
===[[#Abutments|Abutments]]===<br />
<br />
MDOT utilizes the following types of abutments:<br />
<br />
*Curtainwall Abutment (see rigid-gravity retaining wall below);<br />
<br />
<br />
[[File:Fig719-1.png|600px|framed|center|Figure 1. Unreinforced concrete rigid-gravity wall, or curtain wall abutment]]<br />
<br />
<br />
<br />
*Cantilevered Abutment (see semi-gravity retaining wall below)<br />
<br />
<br />
[[File:Fig719-2.png|600px|framed|center|Figure 2. reinforced cantilever abutment wall]]<br />
<br />
<br />
<br />
*Integral and Semi-Integral Abutments – Integral and semi-integral abutments are detailed in the MDOT Bridge Design Guides 6.20.04, 6.20.04B, 6.20.04D.<br />
<br />
Integral abutments are designed to be supported on a single row of piles that are oriented with their webs parallel to the bridge reference line to allow weak axis bending to accommodate superstructure articulation due to thermal gradient and live loading. Splices for piles in integral abutments must be complete joint penetration (CJP). Alternative mechanical splicer channels are not permitted.<br />
<br />
{{top}}<br />
<br />
===[[#Anchored Wall|Anchored Wall]]===<br />
<br />
Anchored walls can consist of ground anchors or tie backs. Verification load testing and proof load testing of the ground anchors is typically performed on all anchors to ensure the actual lateral pullout resistance is within the design tolerances. The verification load testing procedures will be detailed in the contract documents.<br />
<br />
{{top}}<br />
<br />
===[[#Mechanically Stabilized Earth Wall| Mechanically Stabilized Earth Wall]]===<br />
<br />
Below are the basic components of a mechanically stabilized earth (MSE) wall system and a summary of items to review during construction:<br />
<br />
:A. Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed. Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.<br />
<br />
:B. Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office. <br />
<br />
:Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.<br />
<br />
:C. Wire Facing Panels – Wire facing panels are typically specified for temporary MSE walls during Stage I construction. The walls end up being buried into the final structure and are not removed. The wire facing panels in this temporary application are usually black steel due to the short duration of use.<br />
<br />
:D. Soil Reinforcement – MDOT permits the use of steel strip-type (bar or welded wire fabric ladder) reinforcement. Soil reinforcement must be placed as close to perpendicular from the wall face as practical. The reinforcement is permitted to be skewed around piling or other obstructions, but should be done so to not only reduce the skew, but also the number of skewed reinforcement strips. Reinforcement should not be in contact with other reinforcement. For skewed reinforcement soil must be placed between overlapping reinforcement. <br />
<br />
:E. Bolts – Bolts are typically positioned with the head at the bottom side of the connection lug and the washer and nut on the top side. This allows the inspector to visually inspect that the washers and nuts have been installed as the reinforced soil is constructed behind the wall. <br />
<br />
:F. Concrete Facing Panel Joint Material – Geotextile fabric is used to prevent soil particles from moving through the concrete facing panels. If the facing panel joints start to open up then the contractor should double the geotextile over the joints in question to provide additional protection.<br />
<br />
:G. Backfill for Reinforced Soil Mass – Granular soil, typically Granular Material Class II, whic is free draining and meets the required strength and electro-chemical properties. This material must be tested and approved prior to placement.<br />
<br />
:H. Leveling Pad – Is a non-reinforced concrete pad that provides a level starting point for constructing the precast concrete facing panels. A leveling pad is not needed for a wire faced MSE wall.<br />
<br />
:I. Impervious Membrane – A polyvinylchloride (PVC) liner that prevents chloride laden runoff from penetrating into the reinforced soil mass and corroding the steel reinforcement. The liner must be shingle-lapped or seam welded and is positioned to slope away from the front of the wall and extend a minimum distance beyond the end of the soil reinforcement.<br />
<br />
:J. CIP Copings – These copings are typically used as closure pours, but can also run up to 20 feet in length and can overlap adjacent panels without the need for a bond breaker. Expansion joint material is needed when butting CIP coping up to precast coping.<br />
<br />
:K. Foundation Underdrains – Are strategically placed to transport water from the reinforced soil mass to a location far away from the wall. MSE walls are generally not designed for hydrostatic pressure. Foundation underdrains are to be installed at the locations indicated on the plans. The lower foundation underdrains are to be located as low as possible but still drain to either a ditch or a drainage structure.<br />
<br />
MSE Wall Construction Considerations<br />
<br />
*During the wet cure for the concrete bridge deck the water coming off of the deck needs to be collected and discharged away from the MSE wall. Water runoff from the deck may saturate the MSE backfill and cause wall movement.<br />
<br />
*Groundwater needs to be controlled to prevent hydrostatic forces from acting on the wall. If groundwater is encountered during construction the location/number of foundation underdrains may need to be reevaluated.<br />
<br />
*Compaction of the Select Backfill and any subgrade undercuts is important in order to limit any future settlement of the MSE wall fill.<br />
<br />
[[File:Fig719-3.png|600px|framed|center|Figure 1. MSE wall]]<br />
<br />
{{top}}<br />
<br />
===[[#Non-Gravity Cantilevered Retaining Wall| Non-Gravity Cantilevered Retaining Wall]]===<br />
<br />
Examples of on-gravity cantilevered retaining walls are listed below:<br />
*Tangent piles or drilled shafts;<br />
*Drilled shafts or auger-cast piles spanned by structural facing (lagging, panels or shotcrete);<br />
*Steel sheet piling (see Section 704 – Steel Sheet Piling and Cofferdams).<br />
<br />
{{top}}<br />
<br />
===[[#Rigid-Gravity and Semi-Gravity Retaining Wall|Rigid-Gravity and Semi-Gravity Retaining Wall]]===<br />
<br />
[[File:Fig719-4.png|600px|framed|center|Figure 3. Reinforced concrete counterfort semi-gravity wall]]<br />
<br />
<br />
<br />
[[File:Fig719-5.png|600px|framed|center|Figure 4. Reinforced concrete cantilever semi-gravity wall.]]<br />
<br />
{{top}}<br />
<br />
==[[#Measurement and Payment|Measurement and Payment]]==<br />
<br />
{{top}}</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=719_-_Earth_Retaining_Structures&diff=3894719 - Earth Retaining Structures2014-11-14T14:37:16Z<p>HarrisR18: </p>
<hr />
<div><br />
<center><span STYLE="font: 60pt arial;">'''719'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Earth Retaining Structures'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/719%20Earth%20Retaining%Structures.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 719]</center><br />
<br />
==[[#General|General]]==<br />
<br />
Below is a list with definitions of common earth retaining structures utilized by MDOT:<br />
<br />
*Abutment – A structure located at the end of a bridge span that supports the vertical loads from the bridge superstructure, and resists lateral loads from fill material on which the roadway rests immediately adjacent to the bridge.<br />
<br />
*Anchored Wall – An earth retaining system typically composed of the same elements as non-gravity cantilevered walls and that derive additional lateral resistance from one or more tiers of anchors.<br />
<br />
*Mechanically Stabilized Earth (MSE) Wall – A soil-retaining system, employing either strip or grid-type, metallic, or polymeric tensile reinforcements in the soil mass, and a facing element that is either vertical or nearly vertical.<br />
<br />
*Segmental Block Retaining Wall – A soil-retaining system, typically employing polymeric tensile reinforcements in the soil mass attached to a facing element that consists of segmental blocks. Segmental blocks are typically dry cast blocks.<br />
<br />
*Modular Block Retaining Wall – A soil-retaining system that consists of modular blocks stacked to form a gravity wall with a vertical or nearly vertical face. Modular blocks are typically large precast concrete blocks.<br />
<br />
*Non-Gravity Cantilever Retaining Wall – A soil-retaining system that derives lateral resistance through embedment of vertical wall elements and supports retained soil with facing elements. Vertical wall elements may consist of discrete elements (piles, drilled shafts, etc.) or a continuous system (sheet piles, tangent drilled shafts, etc.).<br />
<br />
*Rigid Gravity and Semi-Gravity Retaining Wall – A structure that provides lateral support for a mass of soil and that owes its stability primarily to its own weight and to the weight of any soil located directly above its base.<br />
<br />
Some of these elements may not be detailed on the plans, and may require shop drawing submittals for approval. See 707 of the MDOT Construction Manual for shop drawing requirements.<br />
<br />
{{top}}<br />
<br />
==[[#Materials|Materials]]==<br />
<br />
{{top}}<br />
<br />
<br />
==[[#Construction|Construction]]==<br />
<br />
<br />
<br />
===[[#Abutments|Abutments]]===<br />
<br />
MDOT utilizes the following types of abutments:<br />
<br />
*Curtainwall Abutment (see rigid-gravity retaining wall below);<br />
<br />
<br />
[[File:Fig719-1.png|600px|framed|center|Figure 1. Unreinforced concrete rigid-gravity wall, or curtain wall abutment]]<br />
<br />
<br />
<br />
*Cantilevered Abutment (see semi-gravity retaining wall below)<br />
<br />
<br />
[[File:Fig719-2.png|600px|framed|center|Figure 2. reinforced cantilever abutment wall]]<br />
<br />
<br />
<br />
*Integral and Semi-Integral Abutments – Integral and semi-integral abutments are detailed in the MDOT Bridge Design Guides 6.20.04, 6.20.04B, 6.20.04D.<br />
<br />
Integral abutments are designed to be supported on a single row of piles that are oriented with their webs parallel to the bridge reference line to allow weak axis bending to accommodate superstructure articulation due to thermal gradient and live loading. Splices for piles in integral abutments must be complete joint penetration (CJP). Alternative mechanical splicer channels are not permitted.<br />
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<br />
===[[#Anchored Wall|Anchored Wall]]===<br />
<br />
Anchored walls can consist of ground anchors or tie backs. Verification load testing and proof load testing of the ground anchors is typically performed on all anchors to ensure the actual lateral pullout resistance is within the design tolerances. The verification load testing procedures will be detailed in the contract documents.<br />
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<br />
===[[#Mechanically Stabilized Earth Wall| Mechanically Stabilized Earth Wall]]===<br />
<br />
Below are the basic components of a mechanically stabilized earth (MSE) wall system and a summary of items to review during construction:<br />
<br />
:A. Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed. Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.<br />
<br />
:B. Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office. <br />
<br />
:Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.<br />
<br />
:C. Wire Facing Panels – Wire facing panels are typically specified for temporary MSE walls during Stage I construction. The walls end up being buried into the final structure and are not removed. The wire facing panels in this temporary application are usually black steel due to the short duration of use.<br />
<br />
:D. Soil Reinforcement – MDOT permits the use of steel strip-type (bar or welded wire fabric ladder) reinforcement. Soil reinforcement must be placed as close to perpendicular from the wall face as practical. The reinforcement is permitted to be skewed around piling or other obstructions, but should be done so to not only reduce the skew, but also the number of skewed reinforcement strips. Reinforcement should not be in contact with other reinforcement. For skewed reinforcement soil must be placed between overlapping reinforcement. <br />
<br />
:E. Bolts – Bolts are typically positioned with the head at the bottom side of the connection lug and the washer and nut on the top side. This allows the inspector to visually inspect that the washers and nuts have been installed as the reinforced soil is constructed behind the wall. <br />
<br />
:F. Concrete Facing Panel Joint Material – Geotextile fabric is used to prevent soil particles from moving through the concrete facing panels. If the facing panel joints start to open up then the contractor should double the geotextile over the joints in question to provide additional protection.<br />
<br />
:G. Backfill for Reinforced Soil Mass – Granular soil, typically Granular Material Class II, whic is free draining and meets the required strength and electro-chemical properties. This material must be tested and approved prior to placement.<br />
<br />
:H. Leveling Pad – Is a non-reinforced concrete pad that provides a level starting point for constructing the precast concrete facing panels. A leveling pad is not needed for a wire faced MSE wall.<br />
<br />
:I. Impervious Membrane – A polyvinylchloride (PVC) liner that prevents chloride laden runoff from penetrating into the reinforced soil mass and corroding the steel reinforcement. The liner must be shingle-lapped or seam welded and is positioned to slope away from the front of the wall and extend a minimum distance beyond the end of the soil reinforcement.<br />
<br />
:J. CIP Copings – These copings are typically used as closure pours, but can also run up to 20 feet in length and can overlap adjacent panels without the need for a bond breaker. Expansion joint material is needed when butting CIP coping up to precast coping.<br />
<br />
:K. Foundation Underdrains – Are strategically placed to transport water from the reinforced soil mass to a location far away from the wall. MSE walls are generally not designed for hydrostatic pressure. Foundation underdrains are to be installed at the locations indicated on the plans. The lower foundation underdrains are to be located as low as possible but still drain to either a ditch or a drainage structure.<br />
<br />
MSE Wall Construction Considerations<br />
<br />
*During the wet cure for the concrete bridge deck the water coming off of the deck needs to be collected and discharged away from the MSE wall. Water runoff from the deck may saturate the MSE backfill and cause wall movement.<br />
<br />
*Groundwater needs to be controlled to prevent hydrostatic forces from acting on the wall. If groundwater is encountered during construction the location/number of foundation underdrains may need to be reevaluated.<br />
<br />
*Compaction of the Select Backfill and any subgrade undercuts is important in order to limit any future settlement of the MSE wall fill.<br />
<br />
[[File:Fig719-3.png|600px|framed|center|Figure 1. MSE wall]]<br />
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===[[#Non-Gravity Cantilevered Retaining Wall| Non-Gravity Cantilevered Retaining Wall]]===<br />
<br />
Examples of on-gravity cantilevered retaining walls are listed below:<br />
*Tangent piles or drilled shafts;<br />
*Drilled shafts or auger-cast piles spanned by structural facing (lagging, panels or shotcrete);<br />
*Steel sheet piling (see Section 704 – Steel Sheet Piling and Cofferdams).<br />
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===[[#Rigid-Gravity and Semi-Gravity Retaining Wall|Rigid-Gravity and Semi-Gravity Retaining Wall]]===<br />
<br />
[[File:Fig719-4.png|600px|framed|center|Figure 3. Reinforced concrete counterfort semi-gravity wall]]<br />
<br />
<br />
<br />
[[File:Fig719-5.png|600px|framed|center|Figure 4. Reinforced concrete cantilever semi-gravity wall.]]<br />
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{{top}}</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=718_-_Drilled_Shafts&diff=3891718 - Drilled Shafts2014-11-12T19:36:08Z<p>HarrisR18: /* Mechanically Stabilized Earth Wall */</p>
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<div><br />
<center><span STYLE="font: 60pt arial;">'''718'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Drilled Shafts'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 718]</center><br />
<br />
<br />
==[[#GENERAL|GENERAL]]==<br />
<br />
Drilled shaft foundations are also referred to caissons, drilled piers, or bored piles, and consist of circular shafts of varying diameter, drilled to a design depth, reinforced with a steel rebar cage, and filled with concrete. Drilled shaft foundations can support large loads, and are used when driving steel piles is not feasible, or surrounding structures or utilities are too sensitive to survive the vibrations from steel foundation pile driving operations. Like steel foundation piles, loads from the superstructure transfer into the drilled shafts, which transfer loads to soil layers through side friction, end bearing, or a combination of the two. Drilled shafts are used for bridge foundations, and other ancillary structure foundations such as sign cantilevers and trusses, and signal strain poles.<br />
<br />
Drilled shafts can be constructed in the dry, or in the wet, and can also include a steel casing.<br />
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===[[#DRY CONSTRUCTION METHOD|DRY CONSTRUCTION METHOD]]===<br />
<br />
Dry construction methods are generally used when the water table is below the bottom of the shaft, and the existing soils are stiff enough as not to sloughing or caving into the hole during drilling operations. Any accumulated water greater than 3 inches at the bottom of the shaft must be pumped out prior to rebar and concrete placement, and during concrete placement, water cannot flow into the shaft at a rate greater than 12 inches within 1 hour.<br />
<br />
Typical issues with dry construction methods are if the soils are unstable, or the water table is too high, but the Contractor attempts to force dry shaft construction. In this scenario, soil caving problems will lead to soil inclusions in the shaft concrete, affecting the shaft integrity. If any problems like this arise during construction, contact the Geotechnical Services area.<br />
<br />
Another issue to watch for is if the Contractor leaves the excavation open for too long prior to reinforcement cage and concrete placement. Soils that were capable of maintaining hole stability during the drilling operations may shrink or swell over time and slowly lose that ability, resulting in caving leading to soil inclusions in the shaft concrete affecting the shaft integrity.<br />
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===[[#WET CONSTRUCTION METHOD|WET CONSTRUCTION METHOD]]===<br />
<br />
Wets construction methods are generally used where a dry excavation cannot be maintained during drilling, or shaft concrete placement. This typically occurs in areas of high water tables, and sandy soils that would otherwise slough or cave into the shaft during drilling operations. Water or a polymer slurry is used to contain water seepage, and maintain stability of the shaft excavation. Polymer slurry must be de-sanded and cleaned if used. Temporary surface casings are typically used to ensure shaft alignment. The rebar cage is lowered into the shaft, and concrete is placed using a tremie tube, or concrete pump capable of reaching the bottom of the shaft.<br />
<br />
Typical issues with wet construction methods are inexperienced Contractors that do not understand the mechanics of polymer slurry construction, and the need to ensure proper suspension of sediment and cuttings for removal, and control of caving. This can lead to shafts not being properly cleaned of sediment, resulting in voids, or inclusions in the concrete, affecting the shaft integrity.<br />
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===[[#DRY TEMPORARY CASING METHOD|DRY TEMPORARY CASING METHOD]]===<br />
<br />
Dry temporary cased construction methods are generally used where caving soils occur, over soil or rock deformations are expected, but the casing can maintain a dry and stable excavation. The casing is advanced simultaneously with the excavation. After placement of the rebar cage, the casing is then withdrawn slowly during concrete placement until removed at the top of shaft.<br />
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===[[#WET TEMPORARY CASING METHOD|WET TEMPORARY CASING METHOD]]===<br />
<br />
Wet temporary cased construction methods are generally used where caving soils occur, and a dry excavation cannot be maintained, the soils are too permeable, and the groundwater is higher than the bottom of the shaft. The casing is advanced simultaneously with the excavation, but it is important that no drilling occur outside the casing through any caving soil layers. After placement of the rebar cage, the concrete is placed using a tremie tube or concrete pump capable of reaching the bottom of the shaft. The water in the casing is not to be pumped out, rather it is to be displaced by the concrete placement.<br />
<br />
It is important to ensure the Contractor maintains a positive fluid pressure head in the shaft above the ground water elevation, or material from the side walls of the shaft will be pulled into the bottom of the shaft.<br />
<br />
For both the wet and dry casing methods, the casing is typically installed in a telescoping fashion, where the top casings may be larger than the drilled shaft diameter as called for on the plans. The depth of the hole will also dictate how many sections of casing are to be used. Ensure the contractor does not telescope the casings down to a diameter less than the design diameter as shown on the plans.<br />
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==[[#MATERIALS|MATERIALS]]==<br />
<br />
===[[#Concrete, Grade S2, and Grade T|Concrete, Grade S2, and Grade T]]===<br />
<br />
Ensure concrete materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf section 701] of the Standard Specifications for Construction, except modifications for the slump requirements per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction. Concrete Grade S2 is to be used for dry construction, and Concrete Grade T is to be used for wet construction.<br />
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===[[#Steel Reinforcement|Steel Reinforcement]]===<br />
<br />
Ensure steel reinforcement bars are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/905%20Steel%20Reinforcement.pdf section 905] of the Standard Specifications for Construction. Check the plans and specifications for epoxy rebar requirements.<br />
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===[[#Steel Casing|Steel Casing]]===<br />
<br />
Ensure steel casing materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/919%20Perm%20Traf%20Signs,%20Supports.pdf section 919.10] of the Standard Specifications for Construction. Permanent casing will also require Buy America certification, temporary casings will not, unless left in place.<br />
<br />
Review the plans for temporary casing-left in place cut off elevations. The Contractor is required to provide casing to be smooth and watertight, and capable of withstanding the pressure of concrete and the lateral earth pressures exerted down the length of the shaft. Ensure the outside diameter of the casing is at least equal to the diameter of the shaft as called for on the plans.<br />
<br />
Temporary casings should come equipped with hook holes, or other attachments to aid in the removal as the concrete pour advances. The concrete placement is to be complete prior to complete removal of the casing. The casings should be removed slowly, and with pull forces being in line with the shaft axis. Do not allow the contractor to pull shaft casings with equipment offset from the centerline of the shaft, as this will either disrupt the already placed concrete, or case caving of soil materials into the plastic concrete.<br />
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===[[#Polymer slurry|Polymer slurry]]===<br />
<br />
When wet construction methods are required, polymer type slurry is required. Bentonite slurry is prohibited. Ensure the polymer slurry is of sufficient specific gravity to ensure stability of the excavation during drilling operations, and allows for concrete placement. The Geotechnical Services area will typically review and approve the Contractor’s proposed polymer slurry materials.<br />
<br />
Ensure any polymer slurry used meets the requirements of [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Table 718-1] from the Standard Specifications for Construction. Ensure the Contractor maintains the height of polymer slurry to prevent the side walls of the excavation from caving, and the bottom from heaving.<br />
<br />
Ensure the contractor pre-mixes the polymer slurry materials with clean, fresh water, and allow time for hydration prior to pumping into shaft excavation. The polymer slurry should be agitated to prevent setting up in the shaft.<br />
<br />
If de-sanding is required, ensure the Contractor provides the appropriate equipment. Prior to placement of shaft concrete, take polymer slurry samples with a polymer slurry test kit to determine if heavily contaminated polymer slurry at the bottom of the shaft is to be removed. Ensure the Contractor controls and collects polymer slurry exiting the excavation as the concrete displaces the volume. Review the plans for polymer slurry handling and disposal requirements.<br />
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==[[#CONSTRUCTION|CONSTRUCTION]]==<br />
<br />
===[[#EQUIPMENT|Equipment]]===<br />
<br />
Ensure the contractor is using appropriate equipment to drill the shafts given the site conditions reported in the soil borings, and geotechnical subsurface exploration report. See Figure 1 for a typical drill rig set up. The major components of drill rig include:<br />
<br />
* Crawler or truck mounted auger<br />
* Auger of the appropriate type – rock auger, single or double flight earth auger. See Figure 2 for a double flight earth auger, see Figure 3 for a single flight rock auger.<br />
* Muck or clean out bucket – see Figures 4 and 5 for a muck bucket example.<br />
* Rock core barrel – see Figure 6 for a rock core barrel example.<br />
[[File:Fig 718-1.png|600px|framed|center|Figure 1. Typical drill rig set up]]<br />
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[[File:Fig 718-2.png|600px|framed|center|Figure 2. Double flight earth auger]]<br />
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[[File:Fig 718-3.png|600px|framed|center|Figure 3. Single flight rock auger]]<br />
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[[File:Fig 718-4.png|600px|framed|center|Figure 4. Muck bucket]]<br />
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[[File:Fig 718-5.png|600px|framed|center|Figure 5. Muck bucket bottom]]<br />
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[[File:Fig 718-6.png|600px|framed|center|Figure 6. Soft rock core barrel]]<br />
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===[[#DRILLED SHAFT CONSTRUCTION|DRILLED SHAFT CONSTRUCTION]]===<br />
To track drilled shaft operations, use MDOT [http://mdotcf.state.mi.us/public/webforms/public/1988.pdf form 1988] – DRILLED SHAFT INSPECTION RECORD FOR HIGHWAY SIGNS, LUMINAIRES, AND TRAFFIC SIGNALS.<br />
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====[[#Prior to Drilled Shaft Operations|Prior to Drilled Shaft Operations]]====<br />
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The Contractor is required to submit a Drilled Shaft Installation plan, per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.A] of the Standard Specifications for Construction. This plan is to detail all equipment to be used, the construction sequence, rebar and concrete placement, etc. The Geotechnical Services area will review and approve the Drilled Shaft Installation plan. Review and understand the following:<br />
<br />
* Proposed equipment, including cranes, drills, augers, core barrels, bailing buckets, cleaning equipment, polymer slurry pumps and cleaning equipment, tremie tubes or concrete pumps, and casing.<br />
<br />
* Construction sequence, including methods to ensure a stable excavation, and removal of materials at the bottom of the shaft prior to rebar cage placement.<br />
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* Shaft excavation methods, including proposed excavation methods through supporting and caving soil layers.<br />
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* Method to mix, circulate and de-sand polymer slurry for wet construction methods.<br />
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* Reinforcement placement, including support and centering methods.<br />
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* Concrete placement, including free fall, tremie, or concrete pumping procedures.<br />
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* Methods to prevent drilled shaft excavation spoils from entering waterways, wetlands and floodplains.<br />
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* Fall protection plan conforming to MIOSHA Construction Safety Standards, including a rescue plan for shafts with a diameter of at least 30 inches, and at least 6 feet deep. This must be in place prior to commencement of any drilling operations.<br />
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* Conformance with shaft diameter and rebar requirements based on details shown in the plans.<br />
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Ensure the Contractor has brought all of the proposed equipment as stated in their approved Drilled Shaft Installation plan.<br />
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If the shaft is to be constructed during the wet method, verify if the Contractor is allowed to use water as the drilling fluid, or if polymer slurry is required. Typically, Contractors will want to use water, but water will not prevent caving in deeper shafts. The use of bentonite slurry is prohibited.<br />
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====[[#During Drilling Operations|During Drilling Operations]]====<br />
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Ensure the Contractor performs the following:<br />
<br />
* Check the drilled shaft dimensions and the alignment with reference stakes and plumb bob.<br />
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* Check the dimensions and alignment of the casing inserted in the excavation.<br />
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* Insert a rigid rod assembly with several 90-degree offsets equal to the shaft diameter into the shaft excavation to ensure required diameter.<br />
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* Construction Method Log: The Contractor is required to submit a daily construction method log during drilled shaft excavation and construction per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.5] of the Standard Specifications for Construction. Ensure the following information is shown on the logs:<br />
<br />
* Start dates and completions dates<br />
<br />
* Drilled shaft identification number<br />
<br />
* Location<br />
<br />
* Actual top and bottom elevation of drilled shaft <br />
<br />
* Shaft diameter<br />
<br />
* Final centerline location at top of shaft<br />
<br />
* Variation of drilled shaft from plumb<br />
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* Top and bottom elevation of any permanent casing<br />
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* Description of each soil and rock material encountered during excavating and the top and bottom depths or elevations<br />
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* Depth drilled into bearing stratum<br />
<br />
* Top and bottom elevations of obstructions encountered<br />
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* Amount of obstruction time<br />
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* Depth or elevation of encountered seepage of groundwater<br />
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* Actual volume of concrete placed, compared to the theoretical concrete volume to detect any large void or intrusions of extraneous materials<br />
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* Any remarks to better describe operations.<br />
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Ensure the Contractor maintains the required drilling fluid or polymer slurry levels to prevent caving.<br />
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Construction tolerances – Ensure the drilled shafts are within 3 inches horizontally of centerlines shown on the plans, and the drilled shaft is no more than 1 percent out of plumb, as measured horizontally from the actual center of the shaft at the shaft design top elevation.<br />
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Ensure the Contractor cleans each shaft so at least 50% of the base contains less than ½ inch of sediment. The shaft bottom should have no more than 1 ½ inches of debris above the required bottom elevation. Use a weighted tape to check the bottom of the shaft excavation for debris.<br />
<br />
Marks on the Kelly Bar should be checked to ensure the required bottom of shaft elevation. Monitor the excavation to ensure the expected amount of materials are removed by the auger, if not, caving soils are present.<br />
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Ensure the top elevation of the drilled shaft is from +1 inch to -3 inches from the top of the shaft elevation shown on the plans. For shafts outside of this tolerance range, contact the Geotechnical Services area for recommendations as to corrections. [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Subsection 718.03.C.4] of the Standard Specifications for Construction dictates contractual obligations of the contractor to correct out of tolerance shafts.<br />
<br />
Verify the soil cuttings as they are removed from the auger, and notify the Geotechnical Services area if soil cuttings appear different than those shown on the soil borings. Ensure the Contractor stores soil cuttings away from the drill shaft locations.<br />
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===[[#Obstruction Removal|Obstruction Removal]]===<br />
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Obstructions are to be removed per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.F.2] of the Standard Specifications for Construction. Obstructions may include old concrete foundations, abandoned utilities, or boulders and cobbles. Ensure the Contractor uses tools and procedures as approved by the Geotechnical Services Section to remove the obstructions. Special procedures and tools include:<br />
<br />
* Chisels<br />
* Boulder breakers<br />
* Core barrels<br />
* Air tools<br />
* Hand excavation<br />
* Temporary casing<br />
* Enlarging the drilled shaft diameter<br />
<br />
Removal of obstructions that require special equipment or tools will be measured and paid for as extra work per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.04.D] of the Standard Specifications or Construction. A budget amount will be established to pay for removing obstructions. If the Contractor and the Engineer cannot agree on a lump sum price, the Engineer will direct the work to be done on a force account basis.<br />
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===[[#Placing Steel Reinforcement|Placing Steel Reinforcement]]===<br />
<br />
Check the plans and specifications to verify the Contractor is using the correct size longitudinal bars and lateral or spiral reinforcement, and correct bar lap lengths if used.<br />
<br />
Reinforcing cage – maintain the top of the reinforcing steel cage no greater than 1 inch above, and no greater than 3 inches below the required position. Measure the distance between the top of shaft and the top of reinforcing cage with a straight edge, and direct the Contractor to correct the position if out of tolerance.<br />
<br />
Ensure the Contractor provides a fully assembled steel reinforcement cage for inspection at least two working days before the start of construction. Ensure all longitudinal bars and lateral or spiral reinforcement is properly tied. Ensure plastic spacers are tied at the quarter points around the cage perimeter, but no greater than 30 inches apart.<br />
<br />
Ensure the plastic spacers are spaced at intervals no greater than 5 feet along the length of the cage for #8 bar or smaller, and 10’ for bars larger than #8 to ensure a minimum annular space of 3 inches between the outside of the cage and the side of the excavation or casing. See Figure 7 for an example of plastic spacers on the rebar cage.<br />
<br />
[[File:Fig 718-7.png|600px|framed|center|Figure 7. Rebar cage spacers]]<br />
<br />
Ensure the Contractor does not use concrete blocks, wood blocks, or metal chairs as spacers, as these will not retain the required spacing, and will shift out of position during cage lowering, or during the concrete pour.<br />
<br />
The Contractor may use concrete blocks at the bottom of the shaft to maintain concrete cover over the reinforcement. Ensure the Contractor picks and lowers the reinforcement cage into the shaft in a controlled manner, as not to cause racking or distorting of the tied cage. See Figure 8 for a typical reinforcement cage being lowered into the completed shaft.<br />
<br />
[[File:Fig 718-8.png|600px|framed|center|Figure 8. Rebar cage being lowered into complete shaft]]<br />
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Ensure the Contractor holds down the cage to control vertical displacement during concrete placement or casing extraction.<br />
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===[[#Placing Concrete|Placing Concrete]]===<br />
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Ensure the Contractor places concrete as soon as possible after the excavation and reinforcement cage placement. If too much time has elapsed, loose or soft materials may accumulate at the bottom of the shaft, thus affecting the structural integrity. If this happens, direct the Contractor to remove the reinforcement cage, and remove loose or soft materials.<br />
<br />
Use lighting to inspect the reinforcement cage and side of excavation for dry method construction. Ensure loose materials and groundwater is removed prior to placement of concrete.<br />
<br />
Inspect by probing and measuring the shaft for wet method construction. The Contractor is required to place the concrete in one continuous operation starting from the bottom of the shaft. Once concrete reaches the top of the shaft, inspect the concrete for contaminants, and direct the Contractor to continue concrete placement until good quality concrete flows over the top of the shaft. The concrete should not be vibrated. Ensure the Contractor uses a sump or channel adjacent to the shaft to transmit displaced fluid and concrete away from the shaft opening. If polymer slurry is used, ensure the Contractor collects and disposes of the drilling fluids or polymer slurry appropriately. <br />
<br />
Track the volume of concrete going into the shafts based on tickets, and perform theoretical concrete volume calculation based on the diameter and the length of the shaft. If the numbers vary by too much, it is possible a void is present.<br />
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====[[#Free Fall Concrete Placement|Free Fall Concrete Placement]]====<br />
<br />
Free fall concrete placement can only be done in a dry shaft excavation.<br />
<br />
The falling concrete cannot strike the sides of the excavation or the reinforcing cage. Ensure the Contractor uses a centering drop chute at least 3 feet long. If concrete strikes the sides of the excavation or the reinforcing cage, direct the Contractor to reduce the height of free fall, the rate of concrete flow, or both. The free fall height limit is 80 feet.<br />
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====[[#Tremie Tube Concrete Placement|Tremie Tube Concrete Placement]]====<br />
<br />
Ensure the Contractor is using a tremie tube of at least 10 inches in diameter. Inspect the bottom of the Contractor’s tremie tube to ensure there is a bottom plate, valve, or plug so no water can get into the tube and contaminate the concrete prior to placement.<br />
<br />
The tremie tube must be placed at the bottom of the shaft, and once the plate or plug is removed, or valve is opened, ensure the Contractor keeps the discharge end 5 feet to 10 feet immersed in concrete before raising the tremie tube.<br />
<br />
It is ideal for the concrete to be placed continuously until complete, however, should the Contractor need to withdraw the tremie tube from the concrete, ensure the discharge end is re-sealed, charged with concrete, and inserted back into the concrete at least 10 feet before continuing with the concrete placement.<br />
<br />
For cased shafts, it is important discharge keep a head of concrete above the bottom of casing to be removed, and then remove the casing slowly, to allow the concrete to fill the annular space created by the case thickness. If the concrete level goes down during case extraction, direct the Contractor to stop the extraction, and add more concrete.<br />
<br />
The concrete must be placed in a timely fashion, so the slump does not go below 4”, as the concrete will not properly envelope the rebar cage, or fill the shaft to the required diameter. See Figure 9 for an example of concrete not filling the required shaft diameter.<br />
<br />
Allow the concrete to continue flowing at the top of the shaft, until quality concrete displaces all drilling fluid. Drilling fluid at the top of the shaft may have to be pumped of.<br />
<br />
Ensure the Contractor provides a hand floated surface finish at the top of the shaft concrete per [http://mdotcf.state.mi.us/public/specbook/files/2012/706%20Str%20Conc%20Construction.pdf subsection 706.06.M.2] of the Standard Specifications for Construction.<br />
<br />
* Do not remove the tremie tube from the concrete to take concrete QA samples.<br />
<br />
[[File:Fig 718-9.png|600px|framed|center|Figure 9. Improper concrete placement]]<br />
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<br />
====[[#Pumped Concrete Placement|Pumped Concrete Placement]]====<br />
<br />
Concrete can be pumped for by dry and wet shaft excavations, however, for use in wet excavations, ensure the Contractor provides a pump discharge tube with watertight joints.<br />
<br />
Pumped concrete is very similar to tremie concrete in terms of operations. The main issue to watch is the sway and movement of the pumping pipes during concrete placement. Ensure the Contractor guides or anchors the pumping pipes as to not disturb already placed fresh concrete.<br />
<br />
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<br />
===[[#POST CONSTRUCTION INTEGRITY TESTING|POST CONSTRUCTION INTEGRITY TESTING]]===<br />
<br />
Check the plans and specifications for any type of post construction integrity testing to be done on the completed shaft. There are several methods of non-destructive testing:<br />
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<br />
====[[#Pulse Echo Integrity Testing|Pulse Echo Integrity Testing]]====<br />
<br />
This type of test involves setting an ultrasonic transducer on the surfaces of the concrete, which send wave pulses through the material. Wave pulses will continue through solid concrete until a concrete to air interface, at which time the pulse is reflected back to the transducer, and a depth can be measured. In the presence of voids, the wave would reflect back sooner than expected given the overall thickness of the materials.<br />
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<br />
====[[#Cross Hole Sonic Logging|Cross Hole Sonic Logging]]====<br />
<br />
This type of test involves the attachment of steel access tubes to the vertical cage rebar prior to concrete placement. The concrete is then placed and allowed to cure. Immediately after concrete placement, the steel access tubes are to be filled with water to protect from concrete infiltration. After curing, a sound source and a received are lowered into the steel access tubes, and while keeping them at the same elevation, sonic pulses are emitted from the sound source, and the wave generated is picked up by the receiver. Based on the speed the wave propagates through the material, the receiver maps the integrity of the surrounding concrete, and voids are reported where the wave returns to the receiver at faster rates than sound areas.<br />
<br />
These types of tests are typically performed by a skilled technician, or MDOT prequalified consultant. The [http://www.michigan.gov/mdot/0,4616,7-151-9623_26663_27303-269622--,00.html Geotechnical Services Section] will be present during integrity testing to help analyze and interpret results.<br />
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<br />
====[[#Coring|Coring]]====<br />
<br />
Coring is a destructive test to remove cores of concrete from the finished shaft, and perform testing to determine concrete quality. Coring may also be done when voids are identified during non-destructive tests to reach the detected void. Grout can then be used to fill the void, and the core holes.<br />
<br />
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<br />
==[[#MEASUREMENT AND PAYMENT|MEASUREMENT AND PAYMENT]]==<br />
<br />
<span style="color: red"> -Reserved- </span><br />
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<br />
[[Category:Construction Manual]]<br />
<br />
<br />
<center><span STYLE="font: 60pt arial;">'''719'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Earth Retaining Structures'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/719%20Earth%20Retaining%Structures.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 719]</center><br />
<br />
==[[#General|General]]==<br />
<br />
Below is a list with definitions of common earth retaining structures utilized by MDOT:<br />
<br />
*Abutment – A structure located at the end of a bridge span that supports the vertical loads from the bridge superstructure, and resists lateral loads from fill material on which the roadway rests immediately adjacent to the bridge.<br />
<br />
*Anchored Wall – An earth retaining system typically composed of the same elements as non-gravity cantilevered walls and that derive additional lateral resistance from one or more tiers of anchors.<br />
<br />
*Mechanically Stabilized Earth (MSE) Wall – A soil-retaining system, employing either strip or grid-type, metallic, or polymeric tensile reinforcements in the soil mass, and a facing element that is either vertical or nearly vertical.<br />
<br />
*Segmental Block Retaining Wall – A soil-retaining system, typically employing polymeric tensile reinforcements in the soil mass attached to a facing element that consists of segmental blocks. Segmental blocks are typically dry cast blocks.<br />
<br />
*Modular Block Retaining Wall – A soil-retaining system that consists of modular blocks stacked to form a gravity wall with a vertical or nearly vertical face. Modular blocks are typically large precast concrete blocks.<br />
<br />
*Non-Gravity Cantilever Retaining Wall – A soil-retaining system that derives lateral resistance through embedment of vertical wall elements and supports retained soil with facing elements. Vertical wall elements may consist of discrete elements (piles, drilled shafts, etc.) or a continuous system (sheet piles, tangent drilled shafts, etc.).<br />
<br />
*Rigid Gravity and Semi-Gravity Retaining Wall – A structure that provides lateral support for a mass of soil and that owes its stability primarily to its own weight and to the weight of any soil located directly above its base.<br />
<br />
Some of these elements may not be detailed on the plans, and may require shop drawing submittals for approval. See 707 of the MDOT Construction Manual for shop drawing requirements.<br />
<br />
==[[#Abutments|Abutments]]==<br />
<br />
MDOT utilizes the following types of abutments:<br />
<br />
*Curtainwall Abutment (see rigid-gravity retaining wall below);<br />
<br />
<br />
[[File:Fig719-1.png|600px|framed|center|Figure 1. Unreinforced concrete rigid-gravity wall, or curtain wall abutment]]<br />
<br />
<br />
<br />
*Cantilevered Abutment (see semi-gravity retaining wall below)<br />
<br />
<br />
[[File:Fig719-2.png|600px|framed|center|Figure 2. reinforced cantilever abutment wall]]<br />
<br />
<br />
<br />
*Integral and Semi-Integral Abutments – Integral and semi-integral abutments are detailed in the MDOT Bridge Design Guides 6.20.04, 6.20.04B, 6.20.04D.<br />
<br />
Integral abutments are designed to be supported on a single row of piles that are oriented with their webs parallel to the bridge reference line to allow weak axis bending to accommodate superstructure articulation due to thermal gradient and live loading. Splices for piles in integral abutments must be complete joint penetration (CJP). Alternative mechanical splicer channels are not permitted.<br />
<br />
==[[#Anchored Wall|Anchored Wall]]==<br />
<br />
Anchored walls can consist of ground anchors or tie backs. Verification load testing and proof load testing of the ground anchors is typically performed on all anchors to ensure the actual lateral pullout resistance is within the design tolerances. The verification load testing procedures will be detailed in the contract documents.<br />
<br />
<br />
<br />
==[[#Mechanically Stabilized Earth Wall| Mechanically Stabilized Earth Wall]]==<br />
<br />
Below are the basic components of a mechanically stabilized earth (MSE) wall system and a summary of items to review during construction:<br />
<br />
:A. Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed. Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.<br />
<br />
:B. Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office. <br />
<br />
:Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.<br />
<br />
:C. Wire Facing Panels – Wire facing panels are typically specified for temporary MSE walls during Stage I construction. The walls end up being buried into the final structure and are not removed. The wire facing panels in this temporary application are usually black steel due to the short duration of use.<br />
<br />
:D. Soil Reinforcement – MDOT permits the use of steel strip-type (bar or welded wire fabric ladder) reinforcement. Soil reinforcement must be placed as close to perpendicular from the wall face as practical. The reinforcement is permitted to be skewed around piling or other obstructions, but should be done so to not only reduce the skew, but also the number of skewed reinforcement strips. Reinforcement should not be in contact with other reinforcement. For skewed reinforcement soil must be placed between overlapping reinforcement. <br />
<br />
:E. Bolts – Bolts are typically positioned with the head at the bottom side of the connection lug and the washer and nut on the top side. This allows the inspector to visually inspect that the washers and nuts have been installed as the reinforced soil is constructed behind the wall. <br />
<br />
:F. Concrete Facing Panel Joint Material – Geotextile fabric is used to prevent soil particles from moving through the concrete facing panels. If the facing panel joints start to open up then the contractor should double the geotextile over the joints in question to provide additional protection.<br />
<br />
:G. Backfill for Reinforced Soil Mass – Granular soil, typically Granular Material Class II, whic is free draining and meets the required strength and electro-chemical properties. This material must be tested and approved prior to placement.<br />
<br />
:H. Leveling Pad – Is a non-reinforced concrete pad that provides a level starting point for constructing the precast concrete facing panels. A leveling pad is not needed for a wire faced MSE wall.<br />
<br />
:I. Impervious Membrane – A polyvinylchloride (PVC) liner that prevents chloride laden runoff from penetrating into the reinforced soil mass and corroding the steel reinforcement. The liner must be shingle-lapped or seam welded and is positioned to slope away from the front of the wall and extend a minimum distance beyond the end of the soil reinforcement.<br />
<br />
:J. CIP Copings – These copings are typically used as closure pours, but can also run up to 20 feet in length and can overlap adjacent panels without the need for a bond breaker. Expansion joint material is needed when butting CIP coping up to precast coping.<br />
<br />
:K. Foundation Underdrains – Are strategically placed to transport water from the reinforced soil mass to a location far away from the wall. MSE walls are generally not designed for hydrostatic pressure. Foundation underdrains are to be installed at the locations indicated on the plans. The lower foundation underdrains are to be located as low as possible but still drain to either a ditch or a drainage structure.<br />
<br />
MSE Wall Construction Considerations<br />
<br />
*During the wet cure for the concrete bridge deck the water coming off of the deck needs to be collected and discharged away from the MSE wall. Water runoff from the deck may saturate the MSE backfill and cause wall movement.<br />
<br />
*Groundwater needs to be controlled to prevent hydrostatic forces from acting on the wall. If groundwater is encountered during construction the location/number of foundation underdrains may need to be reevaluated.<br />
<br />
*Compaction of the Select Backfill and any subgrade undercuts is important in order to limit any future settlement of the MSE wall fill.<br />
<br />
[[File:Fig719-3.png|600px|framed|center|Figure 1. MSE wall]]<br />
<br />
==[[#Non-Gravity Cantilevered Retaining Wall| Non-Gravity Cantilevered Retaining Wall]]==<br />
<br />
Examples of on-gravity cantilevered retaining walls are listed below:<br />
*Tangent piles or drilled shafts;<br />
*Drilled shafts or auger-cast piles spanned by structural facing (lagging, panels or shotcrete);<br />
*Steel sheet piling (see Section 704 – Steel Sheet Piling and Cofferdams).<br />
<br />
==[[#Rigid-Gravity and Semi-Gravity Retaining Wall|Rigid-Gravity and Semi-Gravity Retaining Wall]]==<br />
<br />
[[File:Fig719-4.png|600px|framed|center|Figure 3. Reinforced concrete counterfort semi-gravity wall]]<br />
<br />
<br />
<br />
[[File:Fig719-5.png|600px|framed|center|Figure 4. Reinforced concrete cantilever semi-gravity wall.]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=718_-_Drilled_Shafts&diff=3890718 - Drilled Shafts2014-11-12T19:35:39Z<p>HarrisR18: /* Mechanically Stabilized Earth Wall */</p>
<hr />
<div><br />
<center><span STYLE="font: 60pt arial;">'''718'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Drilled Shafts'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 718]</center><br />
<br />
<br />
==[[#GENERAL|GENERAL]]==<br />
<br />
Drilled shaft foundations are also referred to caissons, drilled piers, or bored piles, and consist of circular shafts of varying diameter, drilled to a design depth, reinforced with a steel rebar cage, and filled with concrete. Drilled shaft foundations can support large loads, and are used when driving steel piles is not feasible, or surrounding structures or utilities are too sensitive to survive the vibrations from steel foundation pile driving operations. Like steel foundation piles, loads from the superstructure transfer into the drilled shafts, which transfer loads to soil layers through side friction, end bearing, or a combination of the two. Drilled shafts are used for bridge foundations, and other ancillary structure foundations such as sign cantilevers and trusses, and signal strain poles.<br />
<br />
Drilled shafts can be constructed in the dry, or in the wet, and can also include a steel casing.<br />
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<br />
===[[#DRY CONSTRUCTION METHOD|DRY CONSTRUCTION METHOD]]===<br />
<br />
Dry construction methods are generally used when the water table is below the bottom of the shaft, and the existing soils are stiff enough as not to sloughing or caving into the hole during drilling operations. Any accumulated water greater than 3 inches at the bottom of the shaft must be pumped out prior to rebar and concrete placement, and during concrete placement, water cannot flow into the shaft at a rate greater than 12 inches within 1 hour.<br />
<br />
Typical issues with dry construction methods are if the soils are unstable, or the water table is too high, but the Contractor attempts to force dry shaft construction. In this scenario, soil caving problems will lead to soil inclusions in the shaft concrete, affecting the shaft integrity. If any problems like this arise during construction, contact the Geotechnical Services area.<br />
<br />
Another issue to watch for is if the Contractor leaves the excavation open for too long prior to reinforcement cage and concrete placement. Soils that were capable of maintaining hole stability during the drilling operations may shrink or swell over time and slowly lose that ability, resulting in caving leading to soil inclusions in the shaft concrete affecting the shaft integrity.<br />
<br />
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<br />
===[[#WET CONSTRUCTION METHOD|WET CONSTRUCTION METHOD]]===<br />
<br />
Wets construction methods are generally used where a dry excavation cannot be maintained during drilling, or shaft concrete placement. This typically occurs in areas of high water tables, and sandy soils that would otherwise slough or cave into the shaft during drilling operations. Water or a polymer slurry is used to contain water seepage, and maintain stability of the shaft excavation. Polymer slurry must be de-sanded and cleaned if used. Temporary surface casings are typically used to ensure shaft alignment. The rebar cage is lowered into the shaft, and concrete is placed using a tremie tube, or concrete pump capable of reaching the bottom of the shaft.<br />
<br />
Typical issues with wet construction methods are inexperienced Contractors that do not understand the mechanics of polymer slurry construction, and the need to ensure proper suspension of sediment and cuttings for removal, and control of caving. This can lead to shafts not being properly cleaned of sediment, resulting in voids, or inclusions in the concrete, affecting the shaft integrity.<br />
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<br />
===[[#DRY TEMPORARY CASING METHOD|DRY TEMPORARY CASING METHOD]]===<br />
<br />
Dry temporary cased construction methods are generally used where caving soils occur, over soil or rock deformations are expected, but the casing can maintain a dry and stable excavation. The casing is advanced simultaneously with the excavation. After placement of the rebar cage, the casing is then withdrawn slowly during concrete placement until removed at the top of shaft.<br />
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<br />
===[[#WET TEMPORARY CASING METHOD|WET TEMPORARY CASING METHOD]]===<br />
<br />
Wet temporary cased construction methods are generally used where caving soils occur, and a dry excavation cannot be maintained, the soils are too permeable, and the groundwater is higher than the bottom of the shaft. The casing is advanced simultaneously with the excavation, but it is important that no drilling occur outside the casing through any caving soil layers. After placement of the rebar cage, the concrete is placed using a tremie tube or concrete pump capable of reaching the bottom of the shaft. The water in the casing is not to be pumped out, rather it is to be displaced by the concrete placement.<br />
<br />
It is important to ensure the Contractor maintains a positive fluid pressure head in the shaft above the ground water elevation, or material from the side walls of the shaft will be pulled into the bottom of the shaft.<br />
<br />
For both the wet and dry casing methods, the casing is typically installed in a telescoping fashion, where the top casings may be larger than the drilled shaft diameter as called for on the plans. The depth of the hole will also dictate how many sections of casing are to be used. Ensure the contractor does not telescope the casings down to a diameter less than the design diameter as shown on the plans.<br />
<br />
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<br />
==[[#MATERIALS|MATERIALS]]==<br />
<br />
===[[#Concrete, Grade S2, and Grade T|Concrete, Grade S2, and Grade T]]===<br />
<br />
Ensure concrete materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf section 701] of the Standard Specifications for Construction, except modifications for the slump requirements per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction. Concrete Grade S2 is to be used for dry construction, and Concrete Grade T is to be used for wet construction.<br />
<br />
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<br />
===[[#Steel Reinforcement|Steel Reinforcement]]===<br />
<br />
Ensure steel reinforcement bars are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/905%20Steel%20Reinforcement.pdf section 905] of the Standard Specifications for Construction. Check the plans and specifications for epoxy rebar requirements.<br />
<br />
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<br />
===[[#Steel Casing|Steel Casing]]===<br />
<br />
Ensure steel casing materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/919%20Perm%20Traf%20Signs,%20Supports.pdf section 919.10] of the Standard Specifications for Construction. Permanent casing will also require Buy America certification, temporary casings will not, unless left in place.<br />
<br />
Review the plans for temporary casing-left in place cut off elevations. The Contractor is required to provide casing to be smooth and watertight, and capable of withstanding the pressure of concrete and the lateral earth pressures exerted down the length of the shaft. Ensure the outside diameter of the casing is at least equal to the diameter of the shaft as called for on the plans.<br />
<br />
Temporary casings should come equipped with hook holes, or other attachments to aid in the removal as the concrete pour advances. The concrete placement is to be complete prior to complete removal of the casing. The casings should be removed slowly, and with pull forces being in line with the shaft axis. Do not allow the contractor to pull shaft casings with equipment offset from the centerline of the shaft, as this will either disrupt the already placed concrete, or case caving of soil materials into the plastic concrete.<br />
<br />
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<br />
===[[#Polymer slurry|Polymer slurry]]===<br />
<br />
When wet construction methods are required, polymer type slurry is required. Bentonite slurry is prohibited. Ensure the polymer slurry is of sufficient specific gravity to ensure stability of the excavation during drilling operations, and allows for concrete placement. The Geotechnical Services area will typically review and approve the Contractor’s proposed polymer slurry materials.<br />
<br />
Ensure any polymer slurry used meets the requirements of [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Table 718-1] from the Standard Specifications for Construction. Ensure the Contractor maintains the height of polymer slurry to prevent the side walls of the excavation from caving, and the bottom from heaving.<br />
<br />
Ensure the contractor pre-mixes the polymer slurry materials with clean, fresh water, and allow time for hydration prior to pumping into shaft excavation. The polymer slurry should be agitated to prevent setting up in the shaft.<br />
<br />
If de-sanding is required, ensure the Contractor provides the appropriate equipment. Prior to placement of shaft concrete, take polymer slurry samples with a polymer slurry test kit to determine if heavily contaminated polymer slurry at the bottom of the shaft is to be removed. Ensure the Contractor controls and collects polymer slurry exiting the excavation as the concrete displaces the volume. Review the plans for polymer slurry handling and disposal requirements.<br />
<br />
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<br />
==[[#CONSTRUCTION|CONSTRUCTION]]==<br />
<br />
===[[#EQUIPMENT|Equipment]]===<br />
<br />
Ensure the contractor is using appropriate equipment to drill the shafts given the site conditions reported in the soil borings, and geotechnical subsurface exploration report. See Figure 1 for a typical drill rig set up. The major components of drill rig include:<br />
<br />
* Crawler or truck mounted auger<br />
* Auger of the appropriate type – rock auger, single or double flight earth auger. See Figure 2 for a double flight earth auger, see Figure 3 for a single flight rock auger.<br />
* Muck or clean out bucket – see Figures 4 and 5 for a muck bucket example.<br />
* Rock core barrel – see Figure 6 for a rock core barrel example.<br />
[[File:Fig 718-1.png|600px|framed|center|Figure 1. Typical drill rig set up]]<br />
<br />
[[File:Fig 718-2.png|600px|framed|center|Figure 2. Double flight earth auger]]<br />
<br />
[[File:Fig 718-3.png|600px|framed|center|Figure 3. Single flight rock auger]]<br />
<br />
[[File:Fig 718-4.png|600px|framed|center|Figure 4. Muck bucket]]<br />
<br />
[[File:Fig 718-5.png|600px|framed|center|Figure 5. Muck bucket bottom]]<br />
<br />
[[File:Fig 718-6.png|600px|framed|center|Figure 6. Soft rock core barrel]]<br />
<br />
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<br />
===[[#DRILLED SHAFT CONSTRUCTION|DRILLED SHAFT CONSTRUCTION]]===<br />
To track drilled shaft operations, use MDOT [http://mdotcf.state.mi.us/public/webforms/public/1988.pdf form 1988] – DRILLED SHAFT INSPECTION RECORD FOR HIGHWAY SIGNS, LUMINAIRES, AND TRAFFIC SIGNALS.<br />
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<br />
====[[#Prior to Drilled Shaft Operations|Prior to Drilled Shaft Operations]]====<br />
<br />
The Contractor is required to submit a Drilled Shaft Installation plan, per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.A] of the Standard Specifications for Construction. This plan is to detail all equipment to be used, the construction sequence, rebar and concrete placement, etc. The Geotechnical Services area will review and approve the Drilled Shaft Installation plan. Review and understand the following:<br />
<br />
* Proposed equipment, including cranes, drills, augers, core barrels, bailing buckets, cleaning equipment, polymer slurry pumps and cleaning equipment, tremie tubes or concrete pumps, and casing.<br />
<br />
* Construction sequence, including methods to ensure a stable excavation, and removal of materials at the bottom of the shaft prior to rebar cage placement.<br />
<br />
* Shaft excavation methods, including proposed excavation methods through supporting and caving soil layers.<br />
<br />
* Method to mix, circulate and de-sand polymer slurry for wet construction methods.<br />
<br />
* Reinforcement placement, including support and centering methods.<br />
<br />
* Concrete placement, including free fall, tremie, or concrete pumping procedures.<br />
<br />
* Methods to prevent drilled shaft excavation spoils from entering waterways, wetlands and floodplains.<br />
<br />
* Fall protection plan conforming to MIOSHA Construction Safety Standards, including a rescue plan for shafts with a diameter of at least 30 inches, and at least 6 feet deep. This must be in place prior to commencement of any drilling operations.<br />
<br />
* Conformance with shaft diameter and rebar requirements based on details shown in the plans.<br />
<br />
Ensure the Contractor has brought all of the proposed equipment as stated in their approved Drilled Shaft Installation plan.<br />
<br />
If the shaft is to be constructed during the wet method, verify if the Contractor is allowed to use water as the drilling fluid, or if polymer slurry is required. Typically, Contractors will want to use water, but water will not prevent caving in deeper shafts. The use of bentonite slurry is prohibited.<br />
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<br />
====[[#During Drilling Operations|During Drilling Operations]]====<br />
<br />
Ensure the Contractor performs the following:<br />
<br />
* Check the drilled shaft dimensions and the alignment with reference stakes and plumb bob.<br />
<br />
* Check the dimensions and alignment of the casing inserted in the excavation.<br />
<br />
* Insert a rigid rod assembly with several 90-degree offsets equal to the shaft diameter into the shaft excavation to ensure required diameter.<br />
<br />
* Construction Method Log: The Contractor is required to submit a daily construction method log during drilled shaft excavation and construction per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.5] of the Standard Specifications for Construction. Ensure the following information is shown on the logs:<br />
<br />
* Start dates and completions dates<br />
<br />
* Drilled shaft identification number<br />
<br />
* Location<br />
<br />
* Actual top and bottom elevation of drilled shaft <br />
<br />
* Shaft diameter<br />
<br />
* Final centerline location at top of shaft<br />
<br />
* Variation of drilled shaft from plumb<br />
<br />
* Top and bottom elevation of any permanent casing<br />
<br />
* Description of each soil and rock material encountered during excavating and the top and bottom depths or elevations<br />
<br />
* Depth drilled into bearing stratum<br />
<br />
* Top and bottom elevations of obstructions encountered<br />
<br />
* Amount of obstruction time<br />
<br />
* Depth or elevation of encountered seepage of groundwater<br />
<br />
* Actual volume of concrete placed, compared to the theoretical concrete volume to detect any large void or intrusions of extraneous materials<br />
<br />
* Any remarks to better describe operations.<br />
<br />
Ensure the Contractor maintains the required drilling fluid or polymer slurry levels to prevent caving.<br />
<br />
Construction tolerances – Ensure the drilled shafts are within 3 inches horizontally of centerlines shown on the plans, and the drilled shaft is no more than 1 percent out of plumb, as measured horizontally from the actual center of the shaft at the shaft design top elevation.<br />
<br />
Ensure the Contractor cleans each shaft so at least 50% of the base contains less than ½ inch of sediment. The shaft bottom should have no more than 1 ½ inches of debris above the required bottom elevation. Use a weighted tape to check the bottom of the shaft excavation for debris.<br />
<br />
Marks on the Kelly Bar should be checked to ensure the required bottom of shaft elevation. Monitor the excavation to ensure the expected amount of materials are removed by the auger, if not, caving soils are present.<br />
<br />
Ensure the top elevation of the drilled shaft is from +1 inch to -3 inches from the top of the shaft elevation shown on the plans. For shafts outside of this tolerance range, contact the Geotechnical Services area for recommendations as to corrections. [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Subsection 718.03.C.4] of the Standard Specifications for Construction dictates contractual obligations of the contractor to correct out of tolerance shafts.<br />
<br />
Verify the soil cuttings as they are removed from the auger, and notify the Geotechnical Services area if soil cuttings appear different than those shown on the soil borings. Ensure the Contractor stores soil cuttings away from the drill shaft locations.<br />
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<br />
===[[#Obstruction Removal|Obstruction Removal]]===<br />
<br />
Obstructions are to be removed per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.F.2] of the Standard Specifications for Construction. Obstructions may include old concrete foundations, abandoned utilities, or boulders and cobbles. Ensure the Contractor uses tools and procedures as approved by the Geotechnical Services Section to remove the obstructions. Special procedures and tools include:<br />
<br />
* Chisels<br />
* Boulder breakers<br />
* Core barrels<br />
* Air tools<br />
* Hand excavation<br />
* Temporary casing<br />
* Enlarging the drilled shaft diameter<br />
<br />
Removal of obstructions that require special equipment or tools will be measured and paid for as extra work per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.04.D] of the Standard Specifications or Construction. A budget amount will be established to pay for removing obstructions. If the Contractor and the Engineer cannot agree on a lump sum price, the Engineer will direct the work to be done on a force account basis.<br />
<br />
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<br />
===[[#Placing Steel Reinforcement|Placing Steel Reinforcement]]===<br />
<br />
Check the plans and specifications to verify the Contractor is using the correct size longitudinal bars and lateral or spiral reinforcement, and correct bar lap lengths if used.<br />
<br />
Reinforcing cage – maintain the top of the reinforcing steel cage no greater than 1 inch above, and no greater than 3 inches below the required position. Measure the distance between the top of shaft and the top of reinforcing cage with a straight edge, and direct the Contractor to correct the position if out of tolerance.<br />
<br />
Ensure the Contractor provides a fully assembled steel reinforcement cage for inspection at least two working days before the start of construction. Ensure all longitudinal bars and lateral or spiral reinforcement is properly tied. Ensure plastic spacers are tied at the quarter points around the cage perimeter, but no greater than 30 inches apart.<br />
<br />
Ensure the plastic spacers are spaced at intervals no greater than 5 feet along the length of the cage for #8 bar or smaller, and 10’ for bars larger than #8 to ensure a minimum annular space of 3 inches between the outside of the cage and the side of the excavation or casing. See Figure 7 for an example of plastic spacers on the rebar cage.<br />
<br />
[[File:Fig 718-7.png|600px|framed|center|Figure 7. Rebar cage spacers]]<br />
<br />
Ensure the Contractor does not use concrete blocks, wood blocks, or metal chairs as spacers, as these will not retain the required spacing, and will shift out of position during cage lowering, or during the concrete pour.<br />
<br />
The Contractor may use concrete blocks at the bottom of the shaft to maintain concrete cover over the reinforcement. Ensure the Contractor picks and lowers the reinforcement cage into the shaft in a controlled manner, as not to cause racking or distorting of the tied cage. See Figure 8 for a typical reinforcement cage being lowered into the completed shaft.<br />
<br />
[[File:Fig 718-8.png|600px|framed|center|Figure 8. Rebar cage being lowered into complete shaft]]<br />
<br />
Ensure the Contractor holds down the cage to control vertical displacement during concrete placement or casing extraction.<br />
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<br />
===[[#Placing Concrete|Placing Concrete]]===<br />
<br />
Ensure the Contractor places concrete as soon as possible after the excavation and reinforcement cage placement. If too much time has elapsed, loose or soft materials may accumulate at the bottom of the shaft, thus affecting the structural integrity. If this happens, direct the Contractor to remove the reinforcement cage, and remove loose or soft materials.<br />
<br />
Use lighting to inspect the reinforcement cage and side of excavation for dry method construction. Ensure loose materials and groundwater is removed prior to placement of concrete.<br />
<br />
Inspect by probing and measuring the shaft for wet method construction. The Contractor is required to place the concrete in one continuous operation starting from the bottom of the shaft. Once concrete reaches the top of the shaft, inspect the concrete for contaminants, and direct the Contractor to continue concrete placement until good quality concrete flows over the top of the shaft. The concrete should not be vibrated. Ensure the Contractor uses a sump or channel adjacent to the shaft to transmit displaced fluid and concrete away from the shaft opening. If polymer slurry is used, ensure the Contractor collects and disposes of the drilling fluids or polymer slurry appropriately. <br />
<br />
Track the volume of concrete going into the shafts based on tickets, and perform theoretical concrete volume calculation based on the diameter and the length of the shaft. If the numbers vary by too much, it is possible a void is present.<br />
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<br />
====[[#Free Fall Concrete Placement|Free Fall Concrete Placement]]====<br />
<br />
Free fall concrete placement can only be done in a dry shaft excavation.<br />
<br />
The falling concrete cannot strike the sides of the excavation or the reinforcing cage. Ensure the Contractor uses a centering drop chute at least 3 feet long. If concrete strikes the sides of the excavation or the reinforcing cage, direct the Contractor to reduce the height of free fall, the rate of concrete flow, or both. The free fall height limit is 80 feet.<br />
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<br />
====[[#Tremie Tube Concrete Placement|Tremie Tube Concrete Placement]]====<br />
<br />
Ensure the Contractor is using a tremie tube of at least 10 inches in diameter. Inspect the bottom of the Contractor’s tremie tube to ensure there is a bottom plate, valve, or plug so no water can get into the tube and contaminate the concrete prior to placement.<br />
<br />
The tremie tube must be placed at the bottom of the shaft, and once the plate or plug is removed, or valve is opened, ensure the Contractor keeps the discharge end 5 feet to 10 feet immersed in concrete before raising the tremie tube.<br />
<br />
It is ideal for the concrete to be placed continuously until complete, however, should the Contractor need to withdraw the tremie tube from the concrete, ensure the discharge end is re-sealed, charged with concrete, and inserted back into the concrete at least 10 feet before continuing with the concrete placement.<br />
<br />
For cased shafts, it is important discharge keep a head of concrete above the bottom of casing to be removed, and then remove the casing slowly, to allow the concrete to fill the annular space created by the case thickness. If the concrete level goes down during case extraction, direct the Contractor to stop the extraction, and add more concrete.<br />
<br />
The concrete must be placed in a timely fashion, so the slump does not go below 4”, as the concrete will not properly envelope the rebar cage, or fill the shaft to the required diameter. See Figure 9 for an example of concrete not filling the required shaft diameter.<br />
<br />
Allow the concrete to continue flowing at the top of the shaft, until quality concrete displaces all drilling fluid. Drilling fluid at the top of the shaft may have to be pumped of.<br />
<br />
Ensure the Contractor provides a hand floated surface finish at the top of the shaft concrete per [http://mdotcf.state.mi.us/public/specbook/files/2012/706%20Str%20Conc%20Construction.pdf subsection 706.06.M.2] of the Standard Specifications for Construction.<br />
<br />
* Do not remove the tremie tube from the concrete to take concrete QA samples.<br />
<br />
[[File:Fig 718-9.png|600px|framed|center|Figure 9. Improper concrete placement]]<br />
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<br />
====[[#Pumped Concrete Placement|Pumped Concrete Placement]]====<br />
<br />
Concrete can be pumped for by dry and wet shaft excavations, however, for use in wet excavations, ensure the Contractor provides a pump discharge tube with watertight joints.<br />
<br />
Pumped concrete is very similar to tremie concrete in terms of operations. The main issue to watch is the sway and movement of the pumping pipes during concrete placement. Ensure the Contractor guides or anchors the pumping pipes as to not disturb already placed fresh concrete.<br />
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<br />
===[[#POST CONSTRUCTION INTEGRITY TESTING|POST CONSTRUCTION INTEGRITY TESTING]]===<br />
<br />
Check the plans and specifications for any type of post construction integrity testing to be done on the completed shaft. There are several methods of non-destructive testing:<br />
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<br />
====[[#Pulse Echo Integrity Testing|Pulse Echo Integrity Testing]]====<br />
<br />
This type of test involves setting an ultrasonic transducer on the surfaces of the concrete, which send wave pulses through the material. Wave pulses will continue through solid concrete until a concrete to air interface, at which time the pulse is reflected back to the transducer, and a depth can be measured. In the presence of voids, the wave would reflect back sooner than expected given the overall thickness of the materials.<br />
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<br />
====[[#Cross Hole Sonic Logging|Cross Hole Sonic Logging]]====<br />
<br />
This type of test involves the attachment of steel access tubes to the vertical cage rebar prior to concrete placement. The concrete is then placed and allowed to cure. Immediately after concrete placement, the steel access tubes are to be filled with water to protect from concrete infiltration. After curing, a sound source and a received are lowered into the steel access tubes, and while keeping them at the same elevation, sonic pulses are emitted from the sound source, and the wave generated is picked up by the receiver. Based on the speed the wave propagates through the material, the receiver maps the integrity of the surrounding concrete, and voids are reported where the wave returns to the receiver at faster rates than sound areas.<br />
<br />
These types of tests are typically performed by a skilled technician, or MDOT prequalified consultant. The [http://www.michigan.gov/mdot/0,4616,7-151-9623_26663_27303-269622--,00.html Geotechnical Services Section] will be present during integrity testing to help analyze and interpret results.<br />
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<br />
====[[#Coring|Coring]]====<br />
<br />
Coring is a destructive test to remove cores of concrete from the finished shaft, and perform testing to determine concrete quality. Coring may also be done when voids are identified during non-destructive tests to reach the detected void. Grout can then be used to fill the void, and the core holes.<br />
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<br />
==[[#MEASUREMENT AND PAYMENT|MEASUREMENT AND PAYMENT]]==<br />
<br />
<span style="color: red"> -Reserved- </span><br />
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[[Category:Construction Manual]]<br />
<br />
<br />
<center><span STYLE="font: 60pt arial;">'''719'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Earth Retaining Structures'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/719%20Earth%20Retaining%Structures.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 719]</center><br />
<br />
==[[#General|General]]==<br />
<br />
Below is a list with definitions of common earth retaining structures utilized by MDOT:<br />
<br />
*Abutment – A structure located at the end of a bridge span that supports the vertical loads from the bridge superstructure, and resists lateral loads from fill material on which the roadway rests immediately adjacent to the bridge.<br />
<br />
*Anchored Wall – An earth retaining system typically composed of the same elements as non-gravity cantilevered walls and that derive additional lateral resistance from one or more tiers of anchors.<br />
<br />
*Mechanically Stabilized Earth (MSE) Wall – A soil-retaining system, employing either strip or grid-type, metallic, or polymeric tensile reinforcements in the soil mass, and a facing element that is either vertical or nearly vertical.<br />
<br />
*Segmental Block Retaining Wall – A soil-retaining system, typically employing polymeric tensile reinforcements in the soil mass attached to a facing element that consists of segmental blocks. Segmental blocks are typically dry cast blocks.<br />
<br />
*Modular Block Retaining Wall – A soil-retaining system that consists of modular blocks stacked to form a gravity wall with a vertical or nearly vertical face. Modular blocks are typically large precast concrete blocks.<br />
<br />
*Non-Gravity Cantilever Retaining Wall – A soil-retaining system that derives lateral resistance through embedment of vertical wall elements and supports retained soil with facing elements. Vertical wall elements may consist of discrete elements (piles, drilled shafts, etc.) or a continuous system (sheet piles, tangent drilled shafts, etc.).<br />
<br />
*Rigid Gravity and Semi-Gravity Retaining Wall – A structure that provides lateral support for a mass of soil and that owes its stability primarily to its own weight and to the weight of any soil located directly above its base.<br />
<br />
Some of these elements may not be detailed on the plans, and may require shop drawing submittals for approval. See 707 of the MDOT Construction Manual for shop drawing requirements.<br />
<br />
==[[#Abutments|Abutments]]==<br />
<br />
MDOT utilizes the following types of abutments:<br />
<br />
*Curtainwall Abutment (see rigid-gravity retaining wall below);<br />
<br />
<br />
[[File:Fig719-1.png|600px|framed|center|Figure 1. Unreinforced concrete rigid-gravity wall, or curtain wall abutment]]<br />
<br />
<br />
<br />
*Cantilevered Abutment (see semi-gravity retaining wall below)<br />
<br />
<br />
[[File:Fig719-2.png|600px|framed|center|Figure 2. reinforced cantilever abutment wall]]<br />
<br />
<br />
<br />
*Integral and Semi-Integral Abutments – Integral and semi-integral abutments are detailed in the MDOT Bridge Design Guides 6.20.04, 6.20.04B, 6.20.04D.<br />
<br />
Integral abutments are designed to be supported on a single row of piles that are oriented with their webs parallel to the bridge reference line to allow weak axis bending to accommodate superstructure articulation due to thermal gradient and live loading. Splices for piles in integral abutments must be complete joint penetration (CJP). Alternative mechanical splicer channels are not permitted.<br />
<br />
==[[#Anchored Wall|Anchored Wall]]==<br />
<br />
Anchored walls can consist of ground anchors or tie backs. Verification load testing and proof load testing of the ground anchors is typically performed on all anchors to ensure the actual lateral pullout resistance is within the design tolerances. The verification load testing procedures will be detailed in the contract documents.<br />
<br />
<br />
<br />
==[[#Mechanically Stabilized Earth Wall| Mechanically Stabilized Earth Wall]]==<br />
<br />
Below are the basic components of a mechanically stabilized earth (MSE) wall system and a summary of items to review during construction:<br />
<br />
:A. Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed. Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.<br />
<br />
:B. Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office. <br />
:Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.<br />
<br />
:C. Wire Facing Panels – Wire facing panels are typically specified for temporary MSE walls during Stage I construction. The walls end up being buried into the final structure and are not removed. The wire facing panels in this temporary application are usually black steel due to the short duration of use.<br />
<br />
:D. Soil Reinforcement – MDOT permits the use of steel strip-type (bar or welded wire fabric ladder) reinforcement. Soil reinforcement must be placed as close to perpendicular from the wall face as practical. The reinforcement is permitted to be skewed around piling or other obstructions, but should be done so to not only reduce the skew, but also the number of skewed reinforcement strips. Reinforcement should not be in contact with other reinforcement. For skewed reinforcement soil must be placed between overlapping reinforcement. <br />
<br />
:E. Bolts – Bolts are typically positioned with the head at the bottom side of the connection lug and the washer and nut on the top side. This allows the inspector to visually inspect that the washers and nuts have been installed as the reinforced soil is constructed behind the wall. <br />
<br />
:F. Concrete Facing Panel Joint Material – Geotextile fabric is used to prevent soil particles from moving through the concrete facing panels. If the facing panel joints start to open up then the contractor should double the geotextile over the joints in question to provide additional protection.<br />
<br />
:G. Backfill for Reinforced Soil Mass – Granular soil, typically Granular Material Class II, whic is free draining and meets the required strength and electro-chemical properties. This material must be tested and approved prior to placement.<br />
<br />
:H. Leveling Pad – Is a non-reinforced concrete pad that provides a level starting point for constructing the precast concrete facing panels. A leveling pad is not needed for a wire faced MSE wall.<br />
<br />
:I. Impervious Membrane – A polyvinylchloride (PVC) liner that prevents chloride laden runoff from penetrating into the reinforced soil mass and corroding the steel reinforcement. The liner must be shingle-lapped or seam welded and is positioned to slope away from the front of the wall and extend a minimum distance beyond the end of the soil reinforcement.<br />
<br />
:J. CIP Copings – These copings are typically used as closure pours, but can also run up to 20 feet in length and can overlap adjacent panels without the need for a bond breaker. Expansion joint material is needed when butting CIP coping up to precast coping.<br />
<br />
:K. Foundation Underdrains – Are strategically placed to transport water from the reinforced soil mass to a location far away from the wall. MSE walls are generally not designed for hydrostatic pressure. Foundation underdrains are to be installed at the locations indicated on the plans. The lower foundation underdrains are to be located as low as possible but still drain to either a ditch or a drainage structure.<br />
<br />
MSE Wall Construction Considerations<br />
<br />
*During the wet cure for the concrete bridge deck the water coming off of the deck needs to be collected and discharged away from the MSE wall. Water runoff from the deck may saturate the MSE backfill and cause wall movement.<br />
<br />
*Groundwater needs to be controlled to prevent hydrostatic forces from acting on the wall. If groundwater is encountered during construction the location/number of foundation underdrains may need to be reevaluated.<br />
<br />
*Compaction of the Select Backfill and any subgrade undercuts is important in order to limit any future settlement of the MSE wall fill.<br />
<br />
[[File:Fig719-3.png|600px|framed|center|Figure 1. MSE wall]]<br />
<br />
==[[#Non-Gravity Cantilevered Retaining Wall| Non-Gravity Cantilevered Retaining Wall]]==<br />
<br />
Examples of on-gravity cantilevered retaining walls are listed below:<br />
*Tangent piles or drilled shafts;<br />
*Drilled shafts or auger-cast piles spanned by structural facing (lagging, panels or shotcrete);<br />
*Steel sheet piling (see Section 704 – Steel Sheet Piling and Cofferdams).<br />
<br />
==[[#Rigid-Gravity and Semi-Gravity Retaining Wall|Rigid-Gravity and Semi-Gravity Retaining Wall]]==<br />
<br />
[[File:Fig719-4.png|600px|framed|center|Figure 3. Reinforced concrete counterfort semi-gravity wall]]<br />
<br />
<br />
<br />
[[File:Fig719-5.png|600px|framed|center|Figure 4. Reinforced concrete cantilever semi-gravity wall.]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=718_-_Drilled_Shafts&diff=3889718 - Drilled Shafts2014-11-12T19:35:02Z<p>HarrisR18: /* Mechanically Stabilized Earth Wall */</p>
<hr />
<div><br />
<center><span STYLE="font: 60pt arial;">'''718'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Drilled Shafts'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 718]</center><br />
<br />
<br />
==[[#GENERAL|GENERAL]]==<br />
<br />
Drilled shaft foundations are also referred to caissons, drilled piers, or bored piles, and consist of circular shafts of varying diameter, drilled to a design depth, reinforced with a steel rebar cage, and filled with concrete. Drilled shaft foundations can support large loads, and are used when driving steel piles is not feasible, or surrounding structures or utilities are too sensitive to survive the vibrations from steel foundation pile driving operations. Like steel foundation piles, loads from the superstructure transfer into the drilled shafts, which transfer loads to soil layers through side friction, end bearing, or a combination of the two. Drilled shafts are used for bridge foundations, and other ancillary structure foundations such as sign cantilevers and trusses, and signal strain poles.<br />
<br />
Drilled shafts can be constructed in the dry, or in the wet, and can also include a steel casing.<br />
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<br />
===[[#DRY CONSTRUCTION METHOD|DRY CONSTRUCTION METHOD]]===<br />
<br />
Dry construction methods are generally used when the water table is below the bottom of the shaft, and the existing soils are stiff enough as not to sloughing or caving into the hole during drilling operations. Any accumulated water greater than 3 inches at the bottom of the shaft must be pumped out prior to rebar and concrete placement, and during concrete placement, water cannot flow into the shaft at a rate greater than 12 inches within 1 hour.<br />
<br />
Typical issues with dry construction methods are if the soils are unstable, or the water table is too high, but the Contractor attempts to force dry shaft construction. In this scenario, soil caving problems will lead to soil inclusions in the shaft concrete, affecting the shaft integrity. If any problems like this arise during construction, contact the Geotechnical Services area.<br />
<br />
Another issue to watch for is if the Contractor leaves the excavation open for too long prior to reinforcement cage and concrete placement. Soils that were capable of maintaining hole stability during the drilling operations may shrink or swell over time and slowly lose that ability, resulting in caving leading to soil inclusions in the shaft concrete affecting the shaft integrity.<br />
<br />
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<br />
===[[#WET CONSTRUCTION METHOD|WET CONSTRUCTION METHOD]]===<br />
<br />
Wets construction methods are generally used where a dry excavation cannot be maintained during drilling, or shaft concrete placement. This typically occurs in areas of high water tables, and sandy soils that would otherwise slough or cave into the shaft during drilling operations. Water or a polymer slurry is used to contain water seepage, and maintain stability of the shaft excavation. Polymer slurry must be de-sanded and cleaned if used. Temporary surface casings are typically used to ensure shaft alignment. The rebar cage is lowered into the shaft, and concrete is placed using a tremie tube, or concrete pump capable of reaching the bottom of the shaft.<br />
<br />
Typical issues with wet construction methods are inexperienced Contractors that do not understand the mechanics of polymer slurry construction, and the need to ensure proper suspension of sediment and cuttings for removal, and control of caving. This can lead to shafts not being properly cleaned of sediment, resulting in voids, or inclusions in the concrete, affecting the shaft integrity.<br />
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<br />
===[[#DRY TEMPORARY CASING METHOD|DRY TEMPORARY CASING METHOD]]===<br />
<br />
Dry temporary cased construction methods are generally used where caving soils occur, over soil or rock deformations are expected, but the casing can maintain a dry and stable excavation. The casing is advanced simultaneously with the excavation. After placement of the rebar cage, the casing is then withdrawn slowly during concrete placement until removed at the top of shaft.<br />
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<br />
===[[#WET TEMPORARY CASING METHOD|WET TEMPORARY CASING METHOD]]===<br />
<br />
Wet temporary cased construction methods are generally used where caving soils occur, and a dry excavation cannot be maintained, the soils are too permeable, and the groundwater is higher than the bottom of the shaft. The casing is advanced simultaneously with the excavation, but it is important that no drilling occur outside the casing through any caving soil layers. After placement of the rebar cage, the concrete is placed using a tremie tube or concrete pump capable of reaching the bottom of the shaft. The water in the casing is not to be pumped out, rather it is to be displaced by the concrete placement.<br />
<br />
It is important to ensure the Contractor maintains a positive fluid pressure head in the shaft above the ground water elevation, or material from the side walls of the shaft will be pulled into the bottom of the shaft.<br />
<br />
For both the wet and dry casing methods, the casing is typically installed in a telescoping fashion, where the top casings may be larger than the drilled shaft diameter as called for on the plans. The depth of the hole will also dictate how many sections of casing are to be used. Ensure the contractor does not telescope the casings down to a diameter less than the design diameter as shown on the plans.<br />
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<br />
==[[#MATERIALS|MATERIALS]]==<br />
<br />
===[[#Concrete, Grade S2, and Grade T|Concrete, Grade S2, and Grade T]]===<br />
<br />
Ensure concrete materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf section 701] of the Standard Specifications for Construction, except modifications for the slump requirements per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction. Concrete Grade S2 is to be used for dry construction, and Concrete Grade T is to be used for wet construction.<br />
<br />
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<br />
===[[#Steel Reinforcement|Steel Reinforcement]]===<br />
<br />
Ensure steel reinforcement bars are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/905%20Steel%20Reinforcement.pdf section 905] of the Standard Specifications for Construction. Check the plans and specifications for epoxy rebar requirements.<br />
<br />
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<br />
===[[#Steel Casing|Steel Casing]]===<br />
<br />
Ensure steel casing materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/919%20Perm%20Traf%20Signs,%20Supports.pdf section 919.10] of the Standard Specifications for Construction. Permanent casing will also require Buy America certification, temporary casings will not, unless left in place.<br />
<br />
Review the plans for temporary casing-left in place cut off elevations. The Contractor is required to provide casing to be smooth and watertight, and capable of withstanding the pressure of concrete and the lateral earth pressures exerted down the length of the shaft. Ensure the outside diameter of the casing is at least equal to the diameter of the shaft as called for on the plans.<br />
<br />
Temporary casings should come equipped with hook holes, or other attachments to aid in the removal as the concrete pour advances. The concrete placement is to be complete prior to complete removal of the casing. The casings should be removed slowly, and with pull forces being in line with the shaft axis. Do not allow the contractor to pull shaft casings with equipment offset from the centerline of the shaft, as this will either disrupt the already placed concrete, or case caving of soil materials into the plastic concrete.<br />
<br />
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<br />
===[[#Polymer slurry|Polymer slurry]]===<br />
<br />
When wet construction methods are required, polymer type slurry is required. Bentonite slurry is prohibited. Ensure the polymer slurry is of sufficient specific gravity to ensure stability of the excavation during drilling operations, and allows for concrete placement. The Geotechnical Services area will typically review and approve the Contractor’s proposed polymer slurry materials.<br />
<br />
Ensure any polymer slurry used meets the requirements of [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Table 718-1] from the Standard Specifications for Construction. Ensure the Contractor maintains the height of polymer slurry to prevent the side walls of the excavation from caving, and the bottom from heaving.<br />
<br />
Ensure the contractor pre-mixes the polymer slurry materials with clean, fresh water, and allow time for hydration prior to pumping into shaft excavation. The polymer slurry should be agitated to prevent setting up in the shaft.<br />
<br />
If de-sanding is required, ensure the Contractor provides the appropriate equipment. Prior to placement of shaft concrete, take polymer slurry samples with a polymer slurry test kit to determine if heavily contaminated polymer slurry at the bottom of the shaft is to be removed. Ensure the Contractor controls and collects polymer slurry exiting the excavation as the concrete displaces the volume. Review the plans for polymer slurry handling and disposal requirements.<br />
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<br />
==[[#CONSTRUCTION|CONSTRUCTION]]==<br />
<br />
===[[#EQUIPMENT|Equipment]]===<br />
<br />
Ensure the contractor is using appropriate equipment to drill the shafts given the site conditions reported in the soil borings, and geotechnical subsurface exploration report. See Figure 1 for a typical drill rig set up. The major components of drill rig include:<br />
<br />
* Crawler or truck mounted auger<br />
* Auger of the appropriate type – rock auger, single or double flight earth auger. See Figure 2 for a double flight earth auger, see Figure 3 for a single flight rock auger.<br />
* Muck or clean out bucket – see Figures 4 and 5 for a muck bucket example.<br />
* Rock core barrel – see Figure 6 for a rock core barrel example.<br />
[[File:Fig 718-1.png|600px|framed|center|Figure 1. Typical drill rig set up]]<br />
<br />
[[File:Fig 718-2.png|600px|framed|center|Figure 2. Double flight earth auger]]<br />
<br />
[[File:Fig 718-3.png|600px|framed|center|Figure 3. Single flight rock auger]]<br />
<br />
[[File:Fig 718-4.png|600px|framed|center|Figure 4. Muck bucket]]<br />
<br />
[[File:Fig 718-5.png|600px|framed|center|Figure 5. Muck bucket bottom]]<br />
<br />
[[File:Fig 718-6.png|600px|framed|center|Figure 6. Soft rock core barrel]]<br />
<br />
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<br />
===[[#DRILLED SHAFT CONSTRUCTION|DRILLED SHAFT CONSTRUCTION]]===<br />
To track drilled shaft operations, use MDOT [http://mdotcf.state.mi.us/public/webforms/public/1988.pdf form 1988] – DRILLED SHAFT INSPECTION RECORD FOR HIGHWAY SIGNS, LUMINAIRES, AND TRAFFIC SIGNALS.<br />
<br />
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<br />
====[[#Prior to Drilled Shaft Operations|Prior to Drilled Shaft Operations]]====<br />
<br />
The Contractor is required to submit a Drilled Shaft Installation plan, per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.A] of the Standard Specifications for Construction. This plan is to detail all equipment to be used, the construction sequence, rebar and concrete placement, etc. The Geotechnical Services area will review and approve the Drilled Shaft Installation plan. Review and understand the following:<br />
<br />
* Proposed equipment, including cranes, drills, augers, core barrels, bailing buckets, cleaning equipment, polymer slurry pumps and cleaning equipment, tremie tubes or concrete pumps, and casing.<br />
<br />
* Construction sequence, including methods to ensure a stable excavation, and removal of materials at the bottom of the shaft prior to rebar cage placement.<br />
<br />
* Shaft excavation methods, including proposed excavation methods through supporting and caving soil layers.<br />
<br />
* Method to mix, circulate and de-sand polymer slurry for wet construction methods.<br />
<br />
* Reinforcement placement, including support and centering methods.<br />
<br />
* Concrete placement, including free fall, tremie, or concrete pumping procedures.<br />
<br />
* Methods to prevent drilled shaft excavation spoils from entering waterways, wetlands and floodplains.<br />
<br />
* Fall protection plan conforming to MIOSHA Construction Safety Standards, including a rescue plan for shafts with a diameter of at least 30 inches, and at least 6 feet deep. This must be in place prior to commencement of any drilling operations.<br />
<br />
* Conformance with shaft diameter and rebar requirements based on details shown in the plans.<br />
<br />
Ensure the Contractor has brought all of the proposed equipment as stated in their approved Drilled Shaft Installation plan.<br />
<br />
If the shaft is to be constructed during the wet method, verify if the Contractor is allowed to use water as the drilling fluid, or if polymer slurry is required. Typically, Contractors will want to use water, but water will not prevent caving in deeper shafts. The use of bentonite slurry is prohibited.<br />
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<br />
====[[#During Drilling Operations|During Drilling Operations]]====<br />
<br />
Ensure the Contractor performs the following:<br />
<br />
* Check the drilled shaft dimensions and the alignment with reference stakes and plumb bob.<br />
<br />
* Check the dimensions and alignment of the casing inserted in the excavation.<br />
<br />
* Insert a rigid rod assembly with several 90-degree offsets equal to the shaft diameter into the shaft excavation to ensure required diameter.<br />
<br />
* Construction Method Log: The Contractor is required to submit a daily construction method log during drilled shaft excavation and construction per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.5] of the Standard Specifications for Construction. Ensure the following information is shown on the logs:<br />
<br />
* Start dates and completions dates<br />
<br />
* Drilled shaft identification number<br />
<br />
* Location<br />
<br />
* Actual top and bottom elevation of drilled shaft <br />
<br />
* Shaft diameter<br />
<br />
* Final centerline location at top of shaft<br />
<br />
* Variation of drilled shaft from plumb<br />
<br />
* Top and bottom elevation of any permanent casing<br />
<br />
* Description of each soil and rock material encountered during excavating and the top and bottom depths or elevations<br />
<br />
* Depth drilled into bearing stratum<br />
<br />
* Top and bottom elevations of obstructions encountered<br />
<br />
* Amount of obstruction time<br />
<br />
* Depth or elevation of encountered seepage of groundwater<br />
<br />
* Actual volume of concrete placed, compared to the theoretical concrete volume to detect any large void or intrusions of extraneous materials<br />
<br />
* Any remarks to better describe operations.<br />
<br />
Ensure the Contractor maintains the required drilling fluid or polymer slurry levels to prevent caving.<br />
<br />
Construction tolerances – Ensure the drilled shafts are within 3 inches horizontally of centerlines shown on the plans, and the drilled shaft is no more than 1 percent out of plumb, as measured horizontally from the actual center of the shaft at the shaft design top elevation.<br />
<br />
Ensure the Contractor cleans each shaft so at least 50% of the base contains less than ½ inch of sediment. The shaft bottom should have no more than 1 ½ inches of debris above the required bottom elevation. Use a weighted tape to check the bottom of the shaft excavation for debris.<br />
<br />
Marks on the Kelly Bar should be checked to ensure the required bottom of shaft elevation. Monitor the excavation to ensure the expected amount of materials are removed by the auger, if not, caving soils are present.<br />
<br />
Ensure the top elevation of the drilled shaft is from +1 inch to -3 inches from the top of the shaft elevation shown on the plans. For shafts outside of this tolerance range, contact the Geotechnical Services area for recommendations as to corrections. [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Subsection 718.03.C.4] of the Standard Specifications for Construction dictates contractual obligations of the contractor to correct out of tolerance shafts.<br />
<br />
Verify the soil cuttings as they are removed from the auger, and notify the Geotechnical Services area if soil cuttings appear different than those shown on the soil borings. Ensure the Contractor stores soil cuttings away from the drill shaft locations.<br />
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<br />
===[[#Obstruction Removal|Obstruction Removal]]===<br />
<br />
Obstructions are to be removed per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.F.2] of the Standard Specifications for Construction. Obstructions may include old concrete foundations, abandoned utilities, or boulders and cobbles. Ensure the Contractor uses tools and procedures as approved by the Geotechnical Services Section to remove the obstructions. Special procedures and tools include:<br />
<br />
* Chisels<br />
* Boulder breakers<br />
* Core barrels<br />
* Air tools<br />
* Hand excavation<br />
* Temporary casing<br />
* Enlarging the drilled shaft diameter<br />
<br />
Removal of obstructions that require special equipment or tools will be measured and paid for as extra work per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.04.D] of the Standard Specifications or Construction. A budget amount will be established to pay for removing obstructions. If the Contractor and the Engineer cannot agree on a lump sum price, the Engineer will direct the work to be done on a force account basis.<br />
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<br />
===[[#Placing Steel Reinforcement|Placing Steel Reinforcement]]===<br />
<br />
Check the plans and specifications to verify the Contractor is using the correct size longitudinal bars and lateral or spiral reinforcement, and correct bar lap lengths if used.<br />
<br />
Reinforcing cage – maintain the top of the reinforcing steel cage no greater than 1 inch above, and no greater than 3 inches below the required position. Measure the distance between the top of shaft and the top of reinforcing cage with a straight edge, and direct the Contractor to correct the position if out of tolerance.<br />
<br />
Ensure the Contractor provides a fully assembled steel reinforcement cage for inspection at least two working days before the start of construction. Ensure all longitudinal bars and lateral or spiral reinforcement is properly tied. Ensure plastic spacers are tied at the quarter points around the cage perimeter, but no greater than 30 inches apart.<br />
<br />
Ensure the plastic spacers are spaced at intervals no greater than 5 feet along the length of the cage for #8 bar or smaller, and 10’ for bars larger than #8 to ensure a minimum annular space of 3 inches between the outside of the cage and the side of the excavation or casing. See Figure 7 for an example of plastic spacers on the rebar cage.<br />
<br />
[[File:Fig 718-7.png|600px|framed|center|Figure 7. Rebar cage spacers]]<br />
<br />
Ensure the Contractor does not use concrete blocks, wood blocks, or metal chairs as spacers, as these will not retain the required spacing, and will shift out of position during cage lowering, or during the concrete pour.<br />
<br />
The Contractor may use concrete blocks at the bottom of the shaft to maintain concrete cover over the reinforcement. Ensure the Contractor picks and lowers the reinforcement cage into the shaft in a controlled manner, as not to cause racking or distorting of the tied cage. See Figure 8 for a typical reinforcement cage being lowered into the completed shaft.<br />
<br />
[[File:Fig 718-8.png|600px|framed|center|Figure 8. Rebar cage being lowered into complete shaft]]<br />
<br />
Ensure the Contractor holds down the cage to control vertical displacement during concrete placement or casing extraction.<br />
<br />
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<br />
===[[#Placing Concrete|Placing Concrete]]===<br />
<br />
Ensure the Contractor places concrete as soon as possible after the excavation and reinforcement cage placement. If too much time has elapsed, loose or soft materials may accumulate at the bottom of the shaft, thus affecting the structural integrity. If this happens, direct the Contractor to remove the reinforcement cage, and remove loose or soft materials.<br />
<br />
Use lighting to inspect the reinforcement cage and side of excavation for dry method construction. Ensure loose materials and groundwater is removed prior to placement of concrete.<br />
<br />
Inspect by probing and measuring the shaft for wet method construction. The Contractor is required to place the concrete in one continuous operation starting from the bottom of the shaft. Once concrete reaches the top of the shaft, inspect the concrete for contaminants, and direct the Contractor to continue concrete placement until good quality concrete flows over the top of the shaft. The concrete should not be vibrated. Ensure the Contractor uses a sump or channel adjacent to the shaft to transmit displaced fluid and concrete away from the shaft opening. If polymer slurry is used, ensure the Contractor collects and disposes of the drilling fluids or polymer slurry appropriately. <br />
<br />
Track the volume of concrete going into the shafts based on tickets, and perform theoretical concrete volume calculation based on the diameter and the length of the shaft. If the numbers vary by too much, it is possible a void is present.<br />
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<br />
====[[#Free Fall Concrete Placement|Free Fall Concrete Placement]]====<br />
<br />
Free fall concrete placement can only be done in a dry shaft excavation.<br />
<br />
The falling concrete cannot strike the sides of the excavation or the reinforcing cage. Ensure the Contractor uses a centering drop chute at least 3 feet long. If concrete strikes the sides of the excavation or the reinforcing cage, direct the Contractor to reduce the height of free fall, the rate of concrete flow, or both. The free fall height limit is 80 feet.<br />
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<br />
====[[#Tremie Tube Concrete Placement|Tremie Tube Concrete Placement]]====<br />
<br />
Ensure the Contractor is using a tremie tube of at least 10 inches in diameter. Inspect the bottom of the Contractor’s tremie tube to ensure there is a bottom plate, valve, or plug so no water can get into the tube and contaminate the concrete prior to placement.<br />
<br />
The tremie tube must be placed at the bottom of the shaft, and once the plate or plug is removed, or valve is opened, ensure the Contractor keeps the discharge end 5 feet to 10 feet immersed in concrete before raising the tremie tube.<br />
<br />
It is ideal for the concrete to be placed continuously until complete, however, should the Contractor need to withdraw the tremie tube from the concrete, ensure the discharge end is re-sealed, charged with concrete, and inserted back into the concrete at least 10 feet before continuing with the concrete placement.<br />
<br />
For cased shafts, it is important discharge keep a head of concrete above the bottom of casing to be removed, and then remove the casing slowly, to allow the concrete to fill the annular space created by the case thickness. If the concrete level goes down during case extraction, direct the Contractor to stop the extraction, and add more concrete.<br />
<br />
The concrete must be placed in a timely fashion, so the slump does not go below 4”, as the concrete will not properly envelope the rebar cage, or fill the shaft to the required diameter. See Figure 9 for an example of concrete not filling the required shaft diameter.<br />
<br />
Allow the concrete to continue flowing at the top of the shaft, until quality concrete displaces all drilling fluid. Drilling fluid at the top of the shaft may have to be pumped of.<br />
<br />
Ensure the Contractor provides a hand floated surface finish at the top of the shaft concrete per [http://mdotcf.state.mi.us/public/specbook/files/2012/706%20Str%20Conc%20Construction.pdf subsection 706.06.M.2] of the Standard Specifications for Construction.<br />
<br />
* Do not remove the tremie tube from the concrete to take concrete QA samples.<br />
<br />
[[File:Fig 718-9.png|600px|framed|center|Figure 9. Improper concrete placement]]<br />
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<br />
====[[#Pumped Concrete Placement|Pumped Concrete Placement]]====<br />
<br />
Concrete can be pumped for by dry and wet shaft excavations, however, for use in wet excavations, ensure the Contractor provides a pump discharge tube with watertight joints.<br />
<br />
Pumped concrete is very similar to tremie concrete in terms of operations. The main issue to watch is the sway and movement of the pumping pipes during concrete placement. Ensure the Contractor guides or anchors the pumping pipes as to not disturb already placed fresh concrete.<br />
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<br />
===[[#POST CONSTRUCTION INTEGRITY TESTING|POST CONSTRUCTION INTEGRITY TESTING]]===<br />
<br />
Check the plans and specifications for any type of post construction integrity testing to be done on the completed shaft. There are several methods of non-destructive testing:<br />
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<br />
====[[#Pulse Echo Integrity Testing|Pulse Echo Integrity Testing]]====<br />
<br />
This type of test involves setting an ultrasonic transducer on the surfaces of the concrete, which send wave pulses through the material. Wave pulses will continue through solid concrete until a concrete to air interface, at which time the pulse is reflected back to the transducer, and a depth can be measured. In the presence of voids, the wave would reflect back sooner than expected given the overall thickness of the materials.<br />
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<br />
====[[#Cross Hole Sonic Logging|Cross Hole Sonic Logging]]====<br />
<br />
This type of test involves the attachment of steel access tubes to the vertical cage rebar prior to concrete placement. The concrete is then placed and allowed to cure. Immediately after concrete placement, the steel access tubes are to be filled with water to protect from concrete infiltration. After curing, a sound source and a received are lowered into the steel access tubes, and while keeping them at the same elevation, sonic pulses are emitted from the sound source, and the wave generated is picked up by the receiver. Based on the speed the wave propagates through the material, the receiver maps the integrity of the surrounding concrete, and voids are reported where the wave returns to the receiver at faster rates than sound areas.<br />
<br />
These types of tests are typically performed by a skilled technician, or MDOT prequalified consultant. The [http://www.michigan.gov/mdot/0,4616,7-151-9623_26663_27303-269622--,00.html Geotechnical Services Section] will be present during integrity testing to help analyze and interpret results.<br />
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<br />
====[[#Coring|Coring]]====<br />
<br />
Coring is a destructive test to remove cores of concrete from the finished shaft, and perform testing to determine concrete quality. Coring may also be done when voids are identified during non-destructive tests to reach the detected void. Grout can then be used to fill the void, and the core holes.<br />
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<br />
==[[#MEASUREMENT AND PAYMENT|MEASUREMENT AND PAYMENT]]==<br />
<br />
<span style="color: red"> -Reserved- </span><br />
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<br />
[[Category:Construction Manual]]<br />
<br />
<br />
<center><span STYLE="font: 60pt arial;">'''719'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Earth Retaining Structures'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/719%20Earth%20Retaining%Structures.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 719]</center><br />
<br />
==[[#General|General]]==<br />
<br />
Below is a list with definitions of common earth retaining structures utilized by MDOT:<br />
<br />
*Abutment – A structure located at the end of a bridge span that supports the vertical loads from the bridge superstructure, and resists lateral loads from fill material on which the roadway rests immediately adjacent to the bridge.<br />
<br />
*Anchored Wall – An earth retaining system typically composed of the same elements as non-gravity cantilevered walls and that derive additional lateral resistance from one or more tiers of anchors.<br />
<br />
*Mechanically Stabilized Earth (MSE) Wall – A soil-retaining system, employing either strip or grid-type, metallic, or polymeric tensile reinforcements in the soil mass, and a facing element that is either vertical or nearly vertical.<br />
<br />
*Segmental Block Retaining Wall – A soil-retaining system, typically employing polymeric tensile reinforcements in the soil mass attached to a facing element that consists of segmental blocks. Segmental blocks are typically dry cast blocks.<br />
<br />
*Modular Block Retaining Wall – A soil-retaining system that consists of modular blocks stacked to form a gravity wall with a vertical or nearly vertical face. Modular blocks are typically large precast concrete blocks.<br />
<br />
*Non-Gravity Cantilever Retaining Wall – A soil-retaining system that derives lateral resistance through embedment of vertical wall elements and supports retained soil with facing elements. Vertical wall elements may consist of discrete elements (piles, drilled shafts, etc.) or a continuous system (sheet piles, tangent drilled shafts, etc.).<br />
<br />
*Rigid Gravity and Semi-Gravity Retaining Wall – A structure that provides lateral support for a mass of soil and that owes its stability primarily to its own weight and to the weight of any soil located directly above its base.<br />
<br />
Some of these elements may not be detailed on the plans, and may require shop drawing submittals for approval. See 707 of the MDOT Construction Manual for shop drawing requirements.<br />
<br />
==[[#Abutments|Abutments]]==<br />
<br />
MDOT utilizes the following types of abutments:<br />
<br />
*Curtainwall Abutment (see rigid-gravity retaining wall below);<br />
<br />
<br />
[[File:Fig719-1.png|600px|framed|center|Figure 1. Unreinforced concrete rigid-gravity wall, or curtain wall abutment]]<br />
<br />
<br />
<br />
*Cantilevered Abutment (see semi-gravity retaining wall below)<br />
<br />
<br />
[[File:Fig719-2.png|600px|framed|center|Figure 2. reinforced cantilever abutment wall]]<br />
<br />
<br />
<br />
*Integral and Semi-Integral Abutments – Integral and semi-integral abutments are detailed in the MDOT Bridge Design Guides 6.20.04, 6.20.04B, 6.20.04D.<br />
<br />
Integral abutments are designed to be supported on a single row of piles that are oriented with their webs parallel to the bridge reference line to allow weak axis bending to accommodate superstructure articulation due to thermal gradient and live loading. Splices for piles in integral abutments must be complete joint penetration (CJP). Alternative mechanical splicer channels are not permitted.<br />
<br />
==[[#Anchored Wall|Anchored Wall]]==<br />
<br />
Anchored walls can consist of ground anchors or tie backs. Verification load testing and proof load testing of the ground anchors is typically performed on all anchors to ensure the actual lateral pullout resistance is within the design tolerances. The verification load testing procedures will be detailed in the contract documents.<br />
<br />
<br />
<br />
==[[#Mechanically Stabilized Earth Wall| Mechanically Stabilized Earth Wall]]==<br />
<br />
Below are the basic components of a mechanically stabilized earth (MSE) wall system and a summary of items to review during construction:<br />
<br />
:A.Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed. Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.<br />
<br />
:B.Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office. <br />
Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.<br />
<br />
:C. Wire Facing Panels – Wire facing panels are typically specified for temporary MSE walls during Stage I construction. The walls end up being buried into the final structure and are not removed. The wire facing panels in this temporary application are usually black steel due to the short duration of use.<br />
<br />
:D. Soil Reinforcement – MDOT permits the use of steel strip-type (bar or welded wire fabric ladder) reinforcement. Soil reinforcement must be placed as close to perpendicular from the wall face as practical. The reinforcement is permitted to be skewed around piling or other obstructions, but should be done so to not only reduce the skew, but also the number of skewed reinforcement strips. Reinforcement should not be in contact with other reinforcement. For skewed reinforcement soil must be placed between overlapping reinforcement. <br />
<br />
:E. Bolts – Bolts are typically positioned with the head at the bottom side of the connection lug and the washer and nut on the top side. This allows the inspector to visually inspect that the washers and nuts have been installed as the reinforced soil is constructed behind the wall. <br />
<br />
:F. Concrete Facing Panel Joint Material – Geotextile fabric is used to prevent soil particles from moving through the concrete facing panels. If the facing panel joints start to open up then the contractor should double the geotextile over the joints in question to provide additional protection.<br />
<br />
:G. Backfill for Reinforced Soil Mass – Granular soil, typically Granular Material Class II, whic is free draining and meets the required strength and electro-chemical properties. This material must be tested and approved prior to placement.<br />
<br />
:H. Leveling Pad – Is a non-reinforced concrete pad that provides a level starting point for constructing the precast concrete facing panels. A leveling pad is not needed for a wire faced MSE wall.<br />
<br />
:I. Impervious Membrane – A polyvinylchloride (PVC) liner that prevents chloride laden runoff from penetrating into the reinforced soil mass and corroding the steel reinforcement. The liner must be shingle-lapped or seam welded and is positioned to slope away from the front of the wall and extend a minimum distance beyond the end of the soil reinforcement.<br />
<br />
:J. CIP Copings – These copings are typically used as closure pours, but can also run up to 20 feet in length and can overlap adjacent panels without the need for a bond breaker. Expansion joint material is needed when butting CIP coping up to precast coping.<br />
<br />
:K. Foundation Underdrains – Are strategically placed to transport water from the reinforced soil mass to a location far away from the wall. MSE walls are generally not designed for hydrostatic pressure. Foundation underdrains are to be installed at the locations indicated on the plans. The lower foundation underdrains are to be located as low as possible but still drain to either a ditch or a drainage structure.<br />
<br />
MSE Wall Construction Considerations<br />
<br />
*During the wet cure for the concrete bridge deck the water coming off of the deck needs to be collected and discharged away from the MSE wall. Water runoff from the deck may saturate the MSE backfill and cause wall movement.<br />
<br />
*Groundwater needs to be controlled to prevent hydrostatic forces from acting on the wall. If groundwater is encountered during construction the location/number of foundation underdrains may need to be reevaluated.<br />
<br />
*Compaction of the Select Backfill and any subgrade undercuts is important in order to limit any future settlement of the MSE wall fill.<br />
<br />
[[File:Fig719-3.png|600px|framed|center|Figure 1. MSE wall]]<br />
<br />
==[[#Non-Gravity Cantilevered Retaining Wall| Non-Gravity Cantilevered Retaining Wall]]==<br />
<br />
Examples of on-gravity cantilevered retaining walls are listed below:<br />
*Tangent piles or drilled shafts;<br />
*Drilled shafts or auger-cast piles spanned by structural facing (lagging, panels or shotcrete);<br />
*Steel sheet piling (see Section 704 – Steel Sheet Piling and Cofferdams).<br />
<br />
==[[#Rigid-Gravity and Semi-Gravity Retaining Wall|Rigid-Gravity and Semi-Gravity Retaining Wall]]==<br />
<br />
[[File:Fig719-4.png|600px|framed|center|Figure 3. Reinforced concrete counterfort semi-gravity wall]]<br />
<br />
<br />
<br />
[[File:Fig719-5.png|600px|framed|center|Figure 4. Reinforced concrete cantilever semi-gravity wall.]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=718_-_Drilled_Shafts&diff=3888718 - Drilled Shafts2014-11-12T19:34:03Z<p>HarrisR18: /* Abutments */</p>
<hr />
<div><br />
<center><span STYLE="font: 60pt arial;">'''718'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Drilled Shafts'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 718]</center><br />
<br />
<br />
==[[#GENERAL|GENERAL]]==<br />
<br />
Drilled shaft foundations are also referred to caissons, drilled piers, or bored piles, and consist of circular shafts of varying diameter, drilled to a design depth, reinforced with a steel rebar cage, and filled with concrete. Drilled shaft foundations can support large loads, and are used when driving steel piles is not feasible, or surrounding structures or utilities are too sensitive to survive the vibrations from steel foundation pile driving operations. Like steel foundation piles, loads from the superstructure transfer into the drilled shafts, which transfer loads to soil layers through side friction, end bearing, or a combination of the two. Drilled shafts are used for bridge foundations, and other ancillary structure foundations such as sign cantilevers and trusses, and signal strain poles.<br />
<br />
Drilled shafts can be constructed in the dry, or in the wet, and can also include a steel casing.<br />
<br />
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<br />
===[[#DRY CONSTRUCTION METHOD|DRY CONSTRUCTION METHOD]]===<br />
<br />
Dry construction methods are generally used when the water table is below the bottom of the shaft, and the existing soils are stiff enough as not to sloughing or caving into the hole during drilling operations. Any accumulated water greater than 3 inches at the bottom of the shaft must be pumped out prior to rebar and concrete placement, and during concrete placement, water cannot flow into the shaft at a rate greater than 12 inches within 1 hour.<br />
<br />
Typical issues with dry construction methods are if the soils are unstable, or the water table is too high, but the Contractor attempts to force dry shaft construction. In this scenario, soil caving problems will lead to soil inclusions in the shaft concrete, affecting the shaft integrity. If any problems like this arise during construction, contact the Geotechnical Services area.<br />
<br />
Another issue to watch for is if the Contractor leaves the excavation open for too long prior to reinforcement cage and concrete placement. Soils that were capable of maintaining hole stability during the drilling operations may shrink or swell over time and slowly lose that ability, resulting in caving leading to soil inclusions in the shaft concrete affecting the shaft integrity.<br />
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<br />
===[[#WET CONSTRUCTION METHOD|WET CONSTRUCTION METHOD]]===<br />
<br />
Wets construction methods are generally used where a dry excavation cannot be maintained during drilling, or shaft concrete placement. This typically occurs in areas of high water tables, and sandy soils that would otherwise slough or cave into the shaft during drilling operations. Water or a polymer slurry is used to contain water seepage, and maintain stability of the shaft excavation. Polymer slurry must be de-sanded and cleaned if used. Temporary surface casings are typically used to ensure shaft alignment. The rebar cage is lowered into the shaft, and concrete is placed using a tremie tube, or concrete pump capable of reaching the bottom of the shaft.<br />
<br />
Typical issues with wet construction methods are inexperienced Contractors that do not understand the mechanics of polymer slurry construction, and the need to ensure proper suspension of sediment and cuttings for removal, and control of caving. This can lead to shafts not being properly cleaned of sediment, resulting in voids, or inclusions in the concrete, affecting the shaft integrity.<br />
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===[[#DRY TEMPORARY CASING METHOD|DRY TEMPORARY CASING METHOD]]===<br />
<br />
Dry temporary cased construction methods are generally used where caving soils occur, over soil or rock deformations are expected, but the casing can maintain a dry and stable excavation. The casing is advanced simultaneously with the excavation. After placement of the rebar cage, the casing is then withdrawn slowly during concrete placement until removed at the top of shaft.<br />
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===[[#WET TEMPORARY CASING METHOD|WET TEMPORARY CASING METHOD]]===<br />
<br />
Wet temporary cased construction methods are generally used where caving soils occur, and a dry excavation cannot be maintained, the soils are too permeable, and the groundwater is higher than the bottom of the shaft. The casing is advanced simultaneously with the excavation, but it is important that no drilling occur outside the casing through any caving soil layers. After placement of the rebar cage, the concrete is placed using a tremie tube or concrete pump capable of reaching the bottom of the shaft. The water in the casing is not to be pumped out, rather it is to be displaced by the concrete placement.<br />
<br />
It is important to ensure the Contractor maintains a positive fluid pressure head in the shaft above the ground water elevation, or material from the side walls of the shaft will be pulled into the bottom of the shaft.<br />
<br />
For both the wet and dry casing methods, the casing is typically installed in a telescoping fashion, where the top casings may be larger than the drilled shaft diameter as called for on the plans. The depth of the hole will also dictate how many sections of casing are to be used. Ensure the contractor does not telescope the casings down to a diameter less than the design diameter as shown on the plans.<br />
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==[[#MATERIALS|MATERIALS]]==<br />
<br />
===[[#Concrete, Grade S2, and Grade T|Concrete, Grade S2, and Grade T]]===<br />
<br />
Ensure concrete materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf section 701] of the Standard Specifications for Construction, except modifications for the slump requirements per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction. Concrete Grade S2 is to be used for dry construction, and Concrete Grade T is to be used for wet construction.<br />
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===[[#Steel Reinforcement|Steel Reinforcement]]===<br />
<br />
Ensure steel reinforcement bars are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/905%20Steel%20Reinforcement.pdf section 905] of the Standard Specifications for Construction. Check the plans and specifications for epoxy rebar requirements.<br />
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===[[#Steel Casing|Steel Casing]]===<br />
<br />
Ensure steel casing materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/919%20Perm%20Traf%20Signs,%20Supports.pdf section 919.10] of the Standard Specifications for Construction. Permanent casing will also require Buy America certification, temporary casings will not, unless left in place.<br />
<br />
Review the plans for temporary casing-left in place cut off elevations. The Contractor is required to provide casing to be smooth and watertight, and capable of withstanding the pressure of concrete and the lateral earth pressures exerted down the length of the shaft. Ensure the outside diameter of the casing is at least equal to the diameter of the shaft as called for on the plans.<br />
<br />
Temporary casings should come equipped with hook holes, or other attachments to aid in the removal as the concrete pour advances. The concrete placement is to be complete prior to complete removal of the casing. The casings should be removed slowly, and with pull forces being in line with the shaft axis. Do not allow the contractor to pull shaft casings with equipment offset from the centerline of the shaft, as this will either disrupt the already placed concrete, or case caving of soil materials into the plastic concrete.<br />
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===[[#Polymer slurry|Polymer slurry]]===<br />
<br />
When wet construction methods are required, polymer type slurry is required. Bentonite slurry is prohibited. Ensure the polymer slurry is of sufficient specific gravity to ensure stability of the excavation during drilling operations, and allows for concrete placement. The Geotechnical Services area will typically review and approve the Contractor’s proposed polymer slurry materials.<br />
<br />
Ensure any polymer slurry used meets the requirements of [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Table 718-1] from the Standard Specifications for Construction. Ensure the Contractor maintains the height of polymer slurry to prevent the side walls of the excavation from caving, and the bottom from heaving.<br />
<br />
Ensure the contractor pre-mixes the polymer slurry materials with clean, fresh water, and allow time for hydration prior to pumping into shaft excavation. The polymer slurry should be agitated to prevent setting up in the shaft.<br />
<br />
If de-sanding is required, ensure the Contractor provides the appropriate equipment. Prior to placement of shaft concrete, take polymer slurry samples with a polymer slurry test kit to determine if heavily contaminated polymer slurry at the bottom of the shaft is to be removed. Ensure the Contractor controls and collects polymer slurry exiting the excavation as the concrete displaces the volume. Review the plans for polymer slurry handling and disposal requirements.<br />
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==[[#CONSTRUCTION|CONSTRUCTION]]==<br />
<br />
===[[#EQUIPMENT|Equipment]]===<br />
<br />
Ensure the contractor is using appropriate equipment to drill the shafts given the site conditions reported in the soil borings, and geotechnical subsurface exploration report. See Figure 1 for a typical drill rig set up. The major components of drill rig include:<br />
<br />
* Crawler or truck mounted auger<br />
* Auger of the appropriate type – rock auger, single or double flight earth auger. See Figure 2 for a double flight earth auger, see Figure 3 for a single flight rock auger.<br />
* Muck or clean out bucket – see Figures 4 and 5 for a muck bucket example.<br />
* Rock core barrel – see Figure 6 for a rock core barrel example.<br />
[[File:Fig 718-1.png|600px|framed|center|Figure 1. Typical drill rig set up]]<br />
<br />
[[File:Fig 718-2.png|600px|framed|center|Figure 2. Double flight earth auger]]<br />
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[[File:Fig 718-3.png|600px|framed|center|Figure 3. Single flight rock auger]]<br />
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[[File:Fig 718-4.png|600px|framed|center|Figure 4. Muck bucket]]<br />
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[[File:Fig 718-5.png|600px|framed|center|Figure 5. Muck bucket bottom]]<br />
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[[File:Fig 718-6.png|600px|framed|center|Figure 6. Soft rock core barrel]]<br />
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===[[#DRILLED SHAFT CONSTRUCTION|DRILLED SHAFT CONSTRUCTION]]===<br />
To track drilled shaft operations, use MDOT [http://mdotcf.state.mi.us/public/webforms/public/1988.pdf form 1988] – DRILLED SHAFT INSPECTION RECORD FOR HIGHWAY SIGNS, LUMINAIRES, AND TRAFFIC SIGNALS.<br />
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====[[#Prior to Drilled Shaft Operations|Prior to Drilled Shaft Operations]]====<br />
<br />
The Contractor is required to submit a Drilled Shaft Installation plan, per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.A] of the Standard Specifications for Construction. This plan is to detail all equipment to be used, the construction sequence, rebar and concrete placement, etc. The Geotechnical Services area will review and approve the Drilled Shaft Installation plan. Review and understand the following:<br />
<br />
* Proposed equipment, including cranes, drills, augers, core barrels, bailing buckets, cleaning equipment, polymer slurry pumps and cleaning equipment, tremie tubes or concrete pumps, and casing.<br />
<br />
* Construction sequence, including methods to ensure a stable excavation, and removal of materials at the bottom of the shaft prior to rebar cage placement.<br />
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* Shaft excavation methods, including proposed excavation methods through supporting and caving soil layers.<br />
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* Method to mix, circulate and de-sand polymer slurry for wet construction methods.<br />
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* Reinforcement placement, including support and centering methods.<br />
<br />
* Concrete placement, including free fall, tremie, or concrete pumping procedures.<br />
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* Methods to prevent drilled shaft excavation spoils from entering waterways, wetlands and floodplains.<br />
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* Fall protection plan conforming to MIOSHA Construction Safety Standards, including a rescue plan for shafts with a diameter of at least 30 inches, and at least 6 feet deep. This must be in place prior to commencement of any drilling operations.<br />
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* Conformance with shaft diameter and rebar requirements based on details shown in the plans.<br />
<br />
Ensure the Contractor has brought all of the proposed equipment as stated in their approved Drilled Shaft Installation plan.<br />
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If the shaft is to be constructed during the wet method, verify if the Contractor is allowed to use water as the drilling fluid, or if polymer slurry is required. Typically, Contractors will want to use water, but water will not prevent caving in deeper shafts. The use of bentonite slurry is prohibited.<br />
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====[[#During Drilling Operations|During Drilling Operations]]====<br />
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Ensure the Contractor performs the following:<br />
<br />
* Check the drilled shaft dimensions and the alignment with reference stakes and plumb bob.<br />
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* Check the dimensions and alignment of the casing inserted in the excavation.<br />
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* Insert a rigid rod assembly with several 90-degree offsets equal to the shaft diameter into the shaft excavation to ensure required diameter.<br />
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* Construction Method Log: The Contractor is required to submit a daily construction method log during drilled shaft excavation and construction per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.5] of the Standard Specifications for Construction. Ensure the following information is shown on the logs:<br />
<br />
* Start dates and completions dates<br />
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* Drilled shaft identification number<br />
<br />
* Location<br />
<br />
* Actual top and bottom elevation of drilled shaft <br />
<br />
* Shaft diameter<br />
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* Final centerline location at top of shaft<br />
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* Variation of drilled shaft from plumb<br />
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* Top and bottom elevation of any permanent casing<br />
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* Description of each soil and rock material encountered during excavating and the top and bottom depths or elevations<br />
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* Depth drilled into bearing stratum<br />
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* Top and bottom elevations of obstructions encountered<br />
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* Amount of obstruction time<br />
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* Depth or elevation of encountered seepage of groundwater<br />
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* Actual volume of concrete placed, compared to the theoretical concrete volume to detect any large void or intrusions of extraneous materials<br />
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* Any remarks to better describe operations.<br />
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Ensure the Contractor maintains the required drilling fluid or polymer slurry levels to prevent caving.<br />
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Construction tolerances – Ensure the drilled shafts are within 3 inches horizontally of centerlines shown on the plans, and the drilled shaft is no more than 1 percent out of plumb, as measured horizontally from the actual center of the shaft at the shaft design top elevation.<br />
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Ensure the Contractor cleans each shaft so at least 50% of the base contains less than ½ inch of sediment. The shaft bottom should have no more than 1 ½ inches of debris above the required bottom elevation. Use a weighted tape to check the bottom of the shaft excavation for debris.<br />
<br />
Marks on the Kelly Bar should be checked to ensure the required bottom of shaft elevation. Monitor the excavation to ensure the expected amount of materials are removed by the auger, if not, caving soils are present.<br />
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Ensure the top elevation of the drilled shaft is from +1 inch to -3 inches from the top of the shaft elevation shown on the plans. For shafts outside of this tolerance range, contact the Geotechnical Services area for recommendations as to corrections. [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Subsection 718.03.C.4] of the Standard Specifications for Construction dictates contractual obligations of the contractor to correct out of tolerance shafts.<br />
<br />
Verify the soil cuttings as they are removed from the auger, and notify the Geotechnical Services area if soil cuttings appear different than those shown on the soil borings. Ensure the Contractor stores soil cuttings away from the drill shaft locations.<br />
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===[[#Obstruction Removal|Obstruction Removal]]===<br />
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Obstructions are to be removed per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.F.2] of the Standard Specifications for Construction. Obstructions may include old concrete foundations, abandoned utilities, or boulders and cobbles. Ensure the Contractor uses tools and procedures as approved by the Geotechnical Services Section to remove the obstructions. Special procedures and tools include:<br />
<br />
* Chisels<br />
* Boulder breakers<br />
* Core barrels<br />
* Air tools<br />
* Hand excavation<br />
* Temporary casing<br />
* Enlarging the drilled shaft diameter<br />
<br />
Removal of obstructions that require special equipment or tools will be measured and paid for as extra work per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.04.D] of the Standard Specifications or Construction. A budget amount will be established to pay for removing obstructions. If the Contractor and the Engineer cannot agree on a lump sum price, the Engineer will direct the work to be done on a force account basis.<br />
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===[[#Placing Steel Reinforcement|Placing Steel Reinforcement]]===<br />
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Check the plans and specifications to verify the Contractor is using the correct size longitudinal bars and lateral or spiral reinforcement, and correct bar lap lengths if used.<br />
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Reinforcing cage – maintain the top of the reinforcing steel cage no greater than 1 inch above, and no greater than 3 inches below the required position. Measure the distance between the top of shaft and the top of reinforcing cage with a straight edge, and direct the Contractor to correct the position if out of tolerance.<br />
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Ensure the Contractor provides a fully assembled steel reinforcement cage for inspection at least two working days before the start of construction. Ensure all longitudinal bars and lateral or spiral reinforcement is properly tied. Ensure plastic spacers are tied at the quarter points around the cage perimeter, but no greater than 30 inches apart.<br />
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Ensure the plastic spacers are spaced at intervals no greater than 5 feet along the length of the cage for #8 bar or smaller, and 10’ for bars larger than #8 to ensure a minimum annular space of 3 inches between the outside of the cage and the side of the excavation or casing. See Figure 7 for an example of plastic spacers on the rebar cage.<br />
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[[File:Fig 718-7.png|600px|framed|center|Figure 7. Rebar cage spacers]]<br />
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Ensure the Contractor does not use concrete blocks, wood blocks, or metal chairs as spacers, as these will not retain the required spacing, and will shift out of position during cage lowering, or during the concrete pour.<br />
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The Contractor may use concrete blocks at the bottom of the shaft to maintain concrete cover over the reinforcement. Ensure the Contractor picks and lowers the reinforcement cage into the shaft in a controlled manner, as not to cause racking or distorting of the tied cage. See Figure 8 for a typical reinforcement cage being lowered into the completed shaft.<br />
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[[File:Fig 718-8.png|600px|framed|center|Figure 8. Rebar cage being lowered into complete shaft]]<br />
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Ensure the Contractor holds down the cage to control vertical displacement during concrete placement or casing extraction.<br />
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===[[#Placing Concrete|Placing Concrete]]===<br />
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Ensure the Contractor places concrete as soon as possible after the excavation and reinforcement cage placement. If too much time has elapsed, loose or soft materials may accumulate at the bottom of the shaft, thus affecting the structural integrity. If this happens, direct the Contractor to remove the reinforcement cage, and remove loose or soft materials.<br />
<br />
Use lighting to inspect the reinforcement cage and side of excavation for dry method construction. Ensure loose materials and groundwater is removed prior to placement of concrete.<br />
<br />
Inspect by probing and measuring the shaft for wet method construction. The Contractor is required to place the concrete in one continuous operation starting from the bottom of the shaft. Once concrete reaches the top of the shaft, inspect the concrete for contaminants, and direct the Contractor to continue concrete placement until good quality concrete flows over the top of the shaft. The concrete should not be vibrated. Ensure the Contractor uses a sump or channel adjacent to the shaft to transmit displaced fluid and concrete away from the shaft opening. If polymer slurry is used, ensure the Contractor collects and disposes of the drilling fluids or polymer slurry appropriately. <br />
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Track the volume of concrete going into the shafts based on tickets, and perform theoretical concrete volume calculation based on the diameter and the length of the shaft. If the numbers vary by too much, it is possible a void is present.<br />
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====[[#Free Fall Concrete Placement|Free Fall Concrete Placement]]====<br />
<br />
Free fall concrete placement can only be done in a dry shaft excavation.<br />
<br />
The falling concrete cannot strike the sides of the excavation or the reinforcing cage. Ensure the Contractor uses a centering drop chute at least 3 feet long. If concrete strikes the sides of the excavation or the reinforcing cage, direct the Contractor to reduce the height of free fall, the rate of concrete flow, or both. The free fall height limit is 80 feet.<br />
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====[[#Tremie Tube Concrete Placement|Tremie Tube Concrete Placement]]====<br />
<br />
Ensure the Contractor is using a tremie tube of at least 10 inches in diameter. Inspect the bottom of the Contractor’s tremie tube to ensure there is a bottom plate, valve, or plug so no water can get into the tube and contaminate the concrete prior to placement.<br />
<br />
The tremie tube must be placed at the bottom of the shaft, and once the plate or plug is removed, or valve is opened, ensure the Contractor keeps the discharge end 5 feet to 10 feet immersed in concrete before raising the tremie tube.<br />
<br />
It is ideal for the concrete to be placed continuously until complete, however, should the Contractor need to withdraw the tremie tube from the concrete, ensure the discharge end is re-sealed, charged with concrete, and inserted back into the concrete at least 10 feet before continuing with the concrete placement.<br />
<br />
For cased shafts, it is important discharge keep a head of concrete above the bottom of casing to be removed, and then remove the casing slowly, to allow the concrete to fill the annular space created by the case thickness. If the concrete level goes down during case extraction, direct the Contractor to stop the extraction, and add more concrete.<br />
<br />
The concrete must be placed in a timely fashion, so the slump does not go below 4”, as the concrete will not properly envelope the rebar cage, or fill the shaft to the required diameter. See Figure 9 for an example of concrete not filling the required shaft diameter.<br />
<br />
Allow the concrete to continue flowing at the top of the shaft, until quality concrete displaces all drilling fluid. Drilling fluid at the top of the shaft may have to be pumped of.<br />
<br />
Ensure the Contractor provides a hand floated surface finish at the top of the shaft concrete per [http://mdotcf.state.mi.us/public/specbook/files/2012/706%20Str%20Conc%20Construction.pdf subsection 706.06.M.2] of the Standard Specifications for Construction.<br />
<br />
* Do not remove the tremie tube from the concrete to take concrete QA samples.<br />
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[[File:Fig 718-9.png|600px|framed|center|Figure 9. Improper concrete placement]]<br />
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====[[#Pumped Concrete Placement|Pumped Concrete Placement]]====<br />
<br />
Concrete can be pumped for by dry and wet shaft excavations, however, for use in wet excavations, ensure the Contractor provides a pump discharge tube with watertight joints.<br />
<br />
Pumped concrete is very similar to tremie concrete in terms of operations. The main issue to watch is the sway and movement of the pumping pipes during concrete placement. Ensure the Contractor guides or anchors the pumping pipes as to not disturb already placed fresh concrete.<br />
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===[[#POST CONSTRUCTION INTEGRITY TESTING|POST CONSTRUCTION INTEGRITY TESTING]]===<br />
<br />
Check the plans and specifications for any type of post construction integrity testing to be done on the completed shaft. There are several methods of non-destructive testing:<br />
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====[[#Pulse Echo Integrity Testing|Pulse Echo Integrity Testing]]====<br />
<br />
This type of test involves setting an ultrasonic transducer on the surfaces of the concrete, which send wave pulses through the material. Wave pulses will continue through solid concrete until a concrete to air interface, at which time the pulse is reflected back to the transducer, and a depth can be measured. In the presence of voids, the wave would reflect back sooner than expected given the overall thickness of the materials.<br />
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====[[#Cross Hole Sonic Logging|Cross Hole Sonic Logging]]====<br />
<br />
This type of test involves the attachment of steel access tubes to the vertical cage rebar prior to concrete placement. The concrete is then placed and allowed to cure. Immediately after concrete placement, the steel access tubes are to be filled with water to protect from concrete infiltration. After curing, a sound source and a received are lowered into the steel access tubes, and while keeping them at the same elevation, sonic pulses are emitted from the sound source, and the wave generated is picked up by the receiver. Based on the speed the wave propagates through the material, the receiver maps the integrity of the surrounding concrete, and voids are reported where the wave returns to the receiver at faster rates than sound areas.<br />
<br />
These types of tests are typically performed by a skilled technician, or MDOT prequalified consultant. The [http://www.michigan.gov/mdot/0,4616,7-151-9623_26663_27303-269622--,00.html Geotechnical Services Section] will be present during integrity testing to help analyze and interpret results.<br />
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====[[#Coring|Coring]]====<br />
<br />
Coring is a destructive test to remove cores of concrete from the finished shaft, and perform testing to determine concrete quality. Coring may also be done when voids are identified during non-destructive tests to reach the detected void. Grout can then be used to fill the void, and the core holes.<br />
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==[[#MEASUREMENT AND PAYMENT|MEASUREMENT AND PAYMENT]]==<br />
<br />
<span style="color: red"> -Reserved- </span><br />
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[[Category:Construction Manual]]<br />
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<br />
<center><span STYLE="font: 60pt arial;">'''719'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Earth Retaining Structures'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/719%20Earth%20Retaining%Structures.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 719]</center><br />
<br />
==[[#General|General]]==<br />
<br />
Below is a list with definitions of common earth retaining structures utilized by MDOT:<br />
<br />
*Abutment – A structure located at the end of a bridge span that supports the vertical loads from the bridge superstructure, and resists lateral loads from fill material on which the roadway rests immediately adjacent to the bridge.<br />
<br />
*Anchored Wall – An earth retaining system typically composed of the same elements as non-gravity cantilevered walls and that derive additional lateral resistance from one or more tiers of anchors.<br />
<br />
*Mechanically Stabilized Earth (MSE) Wall – A soil-retaining system, employing either strip or grid-type, metallic, or polymeric tensile reinforcements in the soil mass, and a facing element that is either vertical or nearly vertical.<br />
<br />
*Segmental Block Retaining Wall – A soil-retaining system, typically employing polymeric tensile reinforcements in the soil mass attached to a facing element that consists of segmental blocks. Segmental blocks are typically dry cast blocks.<br />
<br />
*Modular Block Retaining Wall – A soil-retaining system that consists of modular blocks stacked to form a gravity wall with a vertical or nearly vertical face. Modular blocks are typically large precast concrete blocks.<br />
<br />
*Non-Gravity Cantilever Retaining Wall – A soil-retaining system that derives lateral resistance through embedment of vertical wall elements and supports retained soil with facing elements. Vertical wall elements may consist of discrete elements (piles, drilled shafts, etc.) or a continuous system (sheet piles, tangent drilled shafts, etc.).<br />
<br />
*Rigid Gravity and Semi-Gravity Retaining Wall – A structure that provides lateral support for a mass of soil and that owes its stability primarily to its own weight and to the weight of any soil located directly above its base.<br />
<br />
Some of these elements may not be detailed on the plans, and may require shop drawing submittals for approval. See 707 of the MDOT Construction Manual for shop drawing requirements.<br />
<br />
==[[#Abutments|Abutments]]==<br />
<br />
MDOT utilizes the following types of abutments:<br />
<br />
*Curtainwall Abutment (see rigid-gravity retaining wall below);<br />
<br />
<br />
[[File:Fig719-1.png|600px|framed|center|Figure 1. Unreinforced concrete rigid-gravity wall, or curtain wall abutment]]<br />
<br />
<br />
<br />
*Cantilevered Abutment (see semi-gravity retaining wall below)<br />
<br />
<br />
[[File:Fig719-2.png|600px|framed|center|Figure 2. reinforced cantilever abutment wall]]<br />
<br />
<br />
<br />
*Integral and Semi-Integral Abutments – Integral and semi-integral abutments are detailed in the MDOT Bridge Design Guides 6.20.04, 6.20.04B, 6.20.04D.<br />
<br />
Integral abutments are designed to be supported on a single row of piles that are oriented with their webs parallel to the bridge reference line to allow weak axis bending to accommodate superstructure articulation due to thermal gradient and live loading. Splices for piles in integral abutments must be complete joint penetration (CJP). Alternative mechanical splicer channels are not permitted.<br />
<br />
==[[#Anchored Wall|Anchored Wall]]==<br />
<br />
Anchored walls can consist of ground anchors or tie backs. Verification load testing and proof load testing of the ground anchors is typically performed on all anchors to ensure the actual lateral pullout resistance is within the design tolerances. The verification load testing procedures will be detailed in the contract documents.<br />
<br />
<br />
<br />
==[[#Mechanically Stabilized Earth Wall| Mechanically Stabilized Earth Wall]]==<br />
<br />
Below are the basic components of a mechanically stabilized earth (MSE) wall system and a summary of items to review during construction:<br />
<br />
:A.Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed. Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.<br />
<br />
:B.Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office. <br />
Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.<br />
<br />
:C. Wire Facing Panels – Wire facing panels are typically specified for temporary MSE walls during Stage I construction. The walls end up being buried into the final structure and are not removed. The wire facing panels in this temporary application are usually black steel due to the short duration of use.<br />
<br />
:D. Soil Reinforcement – MDOT permits the use of steel strip-type (bar or welded wire fabric ladder) reinforcement. Soil reinforcement must be placed as close to perpendicular from the wall face as practical. The reinforcement is permitted to be skewed around piling or other obstructions, but should be done so to not only reduce the skew, but also the number of skewed reinforcement strips. Reinforcement should not be in contact with other reinforcement. For skewed reinforcement soil must be placed between overlapping reinforcement. <br />
<br />
:E. Bolts – Bolts are typically positioned with the head at the bottom side of the connection lug and the washer and nut on the top side. This allows the inspector to visually inspect that the washers and nuts have been installed as the reinforced soil is constructed behind the wall. <br />
<br />
:F. Concrete Facing Panel Joint Material – Geotextile fabric is used to prevent soil particles from moving through the concrete facing panels. If the facing panel joints start to open up then the contractor should double the geotextile over the joints in question to provide additional protection.<br />
<br />
:G. Backfill for Reinforced Soil Mass – Granular soil, typically Granular Material Class II, whic is free draining and meets the required strength and electro-chemical properties. This material must be tested and approved prior to placement.<br />
<br />
:H. Leveling Pad – Is a non-reinforced concrete pad that provides a level starting point for constructing the precast concrete facing panels. A leveling pad is not needed for a wire faced MSE wall.<br />
<br />
:I. Impervious Membrane – A polyvinylchloride (PVC) liner that prevents chloride laden runoff from penetrating into the reinforced soil mass and corroding the steel reinforcement. The liner must be shingle-lapped or seam welded and is positioned to slope away from the front of the wall and extend a minimum distance beyond the end of the soil reinforcement.<br />
<br />
:J. CIP Copings – These copings are typically used as closure pours, but can also run up to 20 feet in length and can overlap adjacent panels without the need for a bond breaker. Expansion joint material is needed when butting CIP coping up to precast coping.<br />
<br />
:K. Foundation Underdrains – Are strategically placed to transport water from the reinforced soil mass to a location far away from the wall. MSE walls are generally not designed for hydrostatic pressure. Foundation underdrains are to be installed at the locations indicated on the plans. The lower foundation underdrains are to be located as low as possible but still drain to either a ditch or a drainage structure.<br />
<br />
MSE Wall Construction Considerations<br />
<br />
*During the wet cure for the concrete bridge deck the water coming off of the deck needs to be collected and discharged away from the MSE wall. Water runoff from the deck may saturate the MSE backfill and cause wall movement.<br />
<br />
*Groundwater needs to be controlled to prevent hydrostatic forces from acting on the wall. If groundwater is encountered during construction the location/number of foundation underdrains may need to be reevaluated.<br />
<br />
*Compaction of the Select Backfill and any subgrade undercuts is important in order to limit any future settlement of the MSE wall fill.<br />
<br />
[[File:Fig 719-3.png|600px|framed|center|Figure 1. MSE wall]]<br />
<br />
==[[#Non-Gravity Cantilevered Retaining Wall| Non-Gravity Cantilevered Retaining Wall]]==<br />
<br />
Examples of on-gravity cantilevered retaining walls are listed below:<br />
*Tangent piles or drilled shafts;<br />
*Drilled shafts or auger-cast piles spanned by structural facing (lagging, panels or shotcrete);<br />
*Steel sheet piling (see Section 704 – Steel Sheet Piling and Cofferdams).<br />
<br />
==[[#Rigid-Gravity and Semi-Gravity Retaining Wall|Rigid-Gravity and Semi-Gravity Retaining Wall]]==<br />
<br />
[[File:Fig719-4.png|600px|framed|center|Figure 3. Reinforced concrete counterfort semi-gravity wall]]<br />
<br />
<br />
<br />
[[File:Fig719-5.png|600px|framed|center|Figure 4. Reinforced concrete cantilever semi-gravity wall.]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=718_-_Drilled_Shafts&diff=3887718 - Drilled Shafts2014-11-12T19:33:43Z<p>HarrisR18: /* Abutments */</p>
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<div><br />
<center><span STYLE="font: 60pt arial;">'''718'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Drilled Shafts'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 718]</center><br />
<br />
<br />
==[[#GENERAL|GENERAL]]==<br />
<br />
Drilled shaft foundations are also referred to caissons, drilled piers, or bored piles, and consist of circular shafts of varying diameter, drilled to a design depth, reinforced with a steel rebar cage, and filled with concrete. Drilled shaft foundations can support large loads, and are used when driving steel piles is not feasible, or surrounding structures or utilities are too sensitive to survive the vibrations from steel foundation pile driving operations. Like steel foundation piles, loads from the superstructure transfer into the drilled shafts, which transfer loads to soil layers through side friction, end bearing, or a combination of the two. Drilled shafts are used for bridge foundations, and other ancillary structure foundations such as sign cantilevers and trusses, and signal strain poles.<br />
<br />
Drilled shafts can be constructed in the dry, or in the wet, and can also include a steel casing.<br />
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===[[#DRY CONSTRUCTION METHOD|DRY CONSTRUCTION METHOD]]===<br />
<br />
Dry construction methods are generally used when the water table is below the bottom of the shaft, and the existing soils are stiff enough as not to sloughing or caving into the hole during drilling operations. Any accumulated water greater than 3 inches at the bottom of the shaft must be pumped out prior to rebar and concrete placement, and during concrete placement, water cannot flow into the shaft at a rate greater than 12 inches within 1 hour.<br />
<br />
Typical issues with dry construction methods are if the soils are unstable, or the water table is too high, but the Contractor attempts to force dry shaft construction. In this scenario, soil caving problems will lead to soil inclusions in the shaft concrete, affecting the shaft integrity. If any problems like this arise during construction, contact the Geotechnical Services area.<br />
<br />
Another issue to watch for is if the Contractor leaves the excavation open for too long prior to reinforcement cage and concrete placement. Soils that were capable of maintaining hole stability during the drilling operations may shrink or swell over time and slowly lose that ability, resulting in caving leading to soil inclusions in the shaft concrete affecting the shaft integrity.<br />
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===[[#WET CONSTRUCTION METHOD|WET CONSTRUCTION METHOD]]===<br />
<br />
Wets construction methods are generally used where a dry excavation cannot be maintained during drilling, or shaft concrete placement. This typically occurs in areas of high water tables, and sandy soils that would otherwise slough or cave into the shaft during drilling operations. Water or a polymer slurry is used to contain water seepage, and maintain stability of the shaft excavation. Polymer slurry must be de-sanded and cleaned if used. Temporary surface casings are typically used to ensure shaft alignment. The rebar cage is lowered into the shaft, and concrete is placed using a tremie tube, or concrete pump capable of reaching the bottom of the shaft.<br />
<br />
Typical issues with wet construction methods are inexperienced Contractors that do not understand the mechanics of polymer slurry construction, and the need to ensure proper suspension of sediment and cuttings for removal, and control of caving. This can lead to shafts not being properly cleaned of sediment, resulting in voids, or inclusions in the concrete, affecting the shaft integrity.<br />
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===[[#DRY TEMPORARY CASING METHOD|DRY TEMPORARY CASING METHOD]]===<br />
<br />
Dry temporary cased construction methods are generally used where caving soils occur, over soil or rock deformations are expected, but the casing can maintain a dry and stable excavation. The casing is advanced simultaneously with the excavation. After placement of the rebar cage, the casing is then withdrawn slowly during concrete placement until removed at the top of shaft.<br />
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===[[#WET TEMPORARY CASING METHOD|WET TEMPORARY CASING METHOD]]===<br />
<br />
Wet temporary cased construction methods are generally used where caving soils occur, and a dry excavation cannot be maintained, the soils are too permeable, and the groundwater is higher than the bottom of the shaft. The casing is advanced simultaneously with the excavation, but it is important that no drilling occur outside the casing through any caving soil layers. After placement of the rebar cage, the concrete is placed using a tremie tube or concrete pump capable of reaching the bottom of the shaft. The water in the casing is not to be pumped out, rather it is to be displaced by the concrete placement.<br />
<br />
It is important to ensure the Contractor maintains a positive fluid pressure head in the shaft above the ground water elevation, or material from the side walls of the shaft will be pulled into the bottom of the shaft.<br />
<br />
For both the wet and dry casing methods, the casing is typically installed in a telescoping fashion, where the top casings may be larger than the drilled shaft diameter as called for on the plans. The depth of the hole will also dictate how many sections of casing are to be used. Ensure the contractor does not telescope the casings down to a diameter less than the design diameter as shown on the plans.<br />
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==[[#MATERIALS|MATERIALS]]==<br />
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===[[#Concrete, Grade S2, and Grade T|Concrete, Grade S2, and Grade T]]===<br />
<br />
Ensure concrete materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf section 701] of the Standard Specifications for Construction, except modifications for the slump requirements per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction. Concrete Grade S2 is to be used for dry construction, and Concrete Grade T is to be used for wet construction.<br />
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===[[#Steel Reinforcement|Steel Reinforcement]]===<br />
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Ensure steel reinforcement bars are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/905%20Steel%20Reinforcement.pdf section 905] of the Standard Specifications for Construction. Check the plans and specifications for epoxy rebar requirements.<br />
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===[[#Steel Casing|Steel Casing]]===<br />
<br />
Ensure steel casing materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/919%20Perm%20Traf%20Signs,%20Supports.pdf section 919.10] of the Standard Specifications for Construction. Permanent casing will also require Buy America certification, temporary casings will not, unless left in place.<br />
<br />
Review the plans for temporary casing-left in place cut off elevations. The Contractor is required to provide casing to be smooth and watertight, and capable of withstanding the pressure of concrete and the lateral earth pressures exerted down the length of the shaft. Ensure the outside diameter of the casing is at least equal to the diameter of the shaft as called for on the plans.<br />
<br />
Temporary casings should come equipped with hook holes, or other attachments to aid in the removal as the concrete pour advances. The concrete placement is to be complete prior to complete removal of the casing. The casings should be removed slowly, and with pull forces being in line with the shaft axis. Do not allow the contractor to pull shaft casings with equipment offset from the centerline of the shaft, as this will either disrupt the already placed concrete, or case caving of soil materials into the plastic concrete.<br />
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===[[#Polymer slurry|Polymer slurry]]===<br />
<br />
When wet construction methods are required, polymer type slurry is required. Bentonite slurry is prohibited. Ensure the polymer slurry is of sufficient specific gravity to ensure stability of the excavation during drilling operations, and allows for concrete placement. The Geotechnical Services area will typically review and approve the Contractor’s proposed polymer slurry materials.<br />
<br />
Ensure any polymer slurry used meets the requirements of [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Table 718-1] from the Standard Specifications for Construction. Ensure the Contractor maintains the height of polymer slurry to prevent the side walls of the excavation from caving, and the bottom from heaving.<br />
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Ensure the contractor pre-mixes the polymer slurry materials with clean, fresh water, and allow time for hydration prior to pumping into shaft excavation. The polymer slurry should be agitated to prevent setting up in the shaft.<br />
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If de-sanding is required, ensure the Contractor provides the appropriate equipment. Prior to placement of shaft concrete, take polymer slurry samples with a polymer slurry test kit to determine if heavily contaminated polymer slurry at the bottom of the shaft is to be removed. Ensure the Contractor controls and collects polymer slurry exiting the excavation as the concrete displaces the volume. Review the plans for polymer slurry handling and disposal requirements.<br />
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==[[#CONSTRUCTION|CONSTRUCTION]]==<br />
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===[[#EQUIPMENT|Equipment]]===<br />
<br />
Ensure the contractor is using appropriate equipment to drill the shafts given the site conditions reported in the soil borings, and geotechnical subsurface exploration report. See Figure 1 for a typical drill rig set up. The major components of drill rig include:<br />
<br />
* Crawler or truck mounted auger<br />
* Auger of the appropriate type – rock auger, single or double flight earth auger. See Figure 2 for a double flight earth auger, see Figure 3 for a single flight rock auger.<br />
* Muck or clean out bucket – see Figures 4 and 5 for a muck bucket example.<br />
* Rock core barrel – see Figure 6 for a rock core barrel example.<br />
[[File:Fig 718-1.png|600px|framed|center|Figure 1. Typical drill rig set up]]<br />
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[[File:Fig 718-2.png|600px|framed|center|Figure 2. Double flight earth auger]]<br />
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[[File:Fig 718-3.png|600px|framed|center|Figure 3. Single flight rock auger]]<br />
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[[File:Fig 718-4.png|600px|framed|center|Figure 4. Muck bucket]]<br />
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[[File:Fig 718-5.png|600px|framed|center|Figure 5. Muck bucket bottom]]<br />
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[[File:Fig 718-6.png|600px|framed|center|Figure 6. Soft rock core barrel]]<br />
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===[[#DRILLED SHAFT CONSTRUCTION|DRILLED SHAFT CONSTRUCTION]]===<br />
To track drilled shaft operations, use MDOT [http://mdotcf.state.mi.us/public/webforms/public/1988.pdf form 1988] – DRILLED SHAFT INSPECTION RECORD FOR HIGHWAY SIGNS, LUMINAIRES, AND TRAFFIC SIGNALS.<br />
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====[[#Prior to Drilled Shaft Operations|Prior to Drilled Shaft Operations]]====<br />
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The Contractor is required to submit a Drilled Shaft Installation plan, per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.A] of the Standard Specifications for Construction. This plan is to detail all equipment to be used, the construction sequence, rebar and concrete placement, etc. The Geotechnical Services area will review and approve the Drilled Shaft Installation plan. Review and understand the following:<br />
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* Proposed equipment, including cranes, drills, augers, core barrels, bailing buckets, cleaning equipment, polymer slurry pumps and cleaning equipment, tremie tubes or concrete pumps, and casing.<br />
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* Construction sequence, including methods to ensure a stable excavation, and removal of materials at the bottom of the shaft prior to rebar cage placement.<br />
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* Shaft excavation methods, including proposed excavation methods through supporting and caving soil layers.<br />
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* Method to mix, circulate and de-sand polymer slurry for wet construction methods.<br />
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* Reinforcement placement, including support and centering methods.<br />
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* Concrete placement, including free fall, tremie, or concrete pumping procedures.<br />
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* Methods to prevent drilled shaft excavation spoils from entering waterways, wetlands and floodplains.<br />
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* Fall protection plan conforming to MIOSHA Construction Safety Standards, including a rescue plan for shafts with a diameter of at least 30 inches, and at least 6 feet deep. This must be in place prior to commencement of any drilling operations.<br />
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* Conformance with shaft diameter and rebar requirements based on details shown in the plans.<br />
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Ensure the Contractor has brought all of the proposed equipment as stated in their approved Drilled Shaft Installation plan.<br />
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If the shaft is to be constructed during the wet method, verify if the Contractor is allowed to use water as the drilling fluid, or if polymer slurry is required. Typically, Contractors will want to use water, but water will not prevent caving in deeper shafts. The use of bentonite slurry is prohibited.<br />
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====[[#During Drilling Operations|During Drilling Operations]]====<br />
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Ensure the Contractor performs the following:<br />
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* Check the drilled shaft dimensions and the alignment with reference stakes and plumb bob.<br />
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* Check the dimensions and alignment of the casing inserted in the excavation.<br />
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* Insert a rigid rod assembly with several 90-degree offsets equal to the shaft diameter into the shaft excavation to ensure required diameter.<br />
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* Construction Method Log: The Contractor is required to submit a daily construction method log during drilled shaft excavation and construction per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.5] of the Standard Specifications for Construction. Ensure the following information is shown on the logs:<br />
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* Start dates and completions dates<br />
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* Drilled shaft identification number<br />
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* Location<br />
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* Actual top and bottom elevation of drilled shaft <br />
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* Shaft diameter<br />
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* Final centerline location at top of shaft<br />
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* Variation of drilled shaft from plumb<br />
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* Top and bottom elevation of any permanent casing<br />
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* Description of each soil and rock material encountered during excavating and the top and bottom depths or elevations<br />
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* Depth drilled into bearing stratum<br />
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* Top and bottom elevations of obstructions encountered<br />
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* Amount of obstruction time<br />
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* Depth or elevation of encountered seepage of groundwater<br />
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* Actual volume of concrete placed, compared to the theoretical concrete volume to detect any large void or intrusions of extraneous materials<br />
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* Any remarks to better describe operations.<br />
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Ensure the Contractor maintains the required drilling fluid or polymer slurry levels to prevent caving.<br />
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Construction tolerances – Ensure the drilled shafts are within 3 inches horizontally of centerlines shown on the plans, and the drilled shaft is no more than 1 percent out of plumb, as measured horizontally from the actual center of the shaft at the shaft design top elevation.<br />
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Ensure the Contractor cleans each shaft so at least 50% of the base contains less than ½ inch of sediment. The shaft bottom should have no more than 1 ½ inches of debris above the required bottom elevation. Use a weighted tape to check the bottom of the shaft excavation for debris.<br />
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Marks on the Kelly Bar should be checked to ensure the required bottom of shaft elevation. Monitor the excavation to ensure the expected amount of materials are removed by the auger, if not, caving soils are present.<br />
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Ensure the top elevation of the drilled shaft is from +1 inch to -3 inches from the top of the shaft elevation shown on the plans. For shafts outside of this tolerance range, contact the Geotechnical Services area for recommendations as to corrections. [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Subsection 718.03.C.4] of the Standard Specifications for Construction dictates contractual obligations of the contractor to correct out of tolerance shafts.<br />
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Verify the soil cuttings as they are removed from the auger, and notify the Geotechnical Services area if soil cuttings appear different than those shown on the soil borings. Ensure the Contractor stores soil cuttings away from the drill shaft locations.<br />
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===[[#Obstruction Removal|Obstruction Removal]]===<br />
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Obstructions are to be removed per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.F.2] of the Standard Specifications for Construction. Obstructions may include old concrete foundations, abandoned utilities, or boulders and cobbles. Ensure the Contractor uses tools and procedures as approved by the Geotechnical Services Section to remove the obstructions. Special procedures and tools include:<br />
<br />
* Chisels<br />
* Boulder breakers<br />
* Core barrels<br />
* Air tools<br />
* Hand excavation<br />
* Temporary casing<br />
* Enlarging the drilled shaft diameter<br />
<br />
Removal of obstructions that require special equipment or tools will be measured and paid for as extra work per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.04.D] of the Standard Specifications or Construction. A budget amount will be established to pay for removing obstructions. If the Contractor and the Engineer cannot agree on a lump sum price, the Engineer will direct the work to be done on a force account basis.<br />
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===[[#Placing Steel Reinforcement|Placing Steel Reinforcement]]===<br />
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Check the plans and specifications to verify the Contractor is using the correct size longitudinal bars and lateral or spiral reinforcement, and correct bar lap lengths if used.<br />
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Reinforcing cage – maintain the top of the reinforcing steel cage no greater than 1 inch above, and no greater than 3 inches below the required position. Measure the distance between the top of shaft and the top of reinforcing cage with a straight edge, and direct the Contractor to correct the position if out of tolerance.<br />
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Ensure the Contractor provides a fully assembled steel reinforcement cage for inspection at least two working days before the start of construction. Ensure all longitudinal bars and lateral or spiral reinforcement is properly tied. Ensure plastic spacers are tied at the quarter points around the cage perimeter, but no greater than 30 inches apart.<br />
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Ensure the plastic spacers are spaced at intervals no greater than 5 feet along the length of the cage for #8 bar or smaller, and 10’ for bars larger than #8 to ensure a minimum annular space of 3 inches between the outside of the cage and the side of the excavation or casing. See Figure 7 for an example of plastic spacers on the rebar cage.<br />
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[[File:Fig 718-7.png|600px|framed|center|Figure 7. Rebar cage spacers]]<br />
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Ensure the Contractor does not use concrete blocks, wood blocks, or metal chairs as spacers, as these will not retain the required spacing, and will shift out of position during cage lowering, or during the concrete pour.<br />
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The Contractor may use concrete blocks at the bottom of the shaft to maintain concrete cover over the reinforcement. Ensure the Contractor picks and lowers the reinforcement cage into the shaft in a controlled manner, as not to cause racking or distorting of the tied cage. See Figure 8 for a typical reinforcement cage being lowered into the completed shaft.<br />
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[[File:Fig 718-8.png|600px|framed|center|Figure 8. Rebar cage being lowered into complete shaft]]<br />
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Ensure the Contractor holds down the cage to control vertical displacement during concrete placement or casing extraction.<br />
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===[[#Placing Concrete|Placing Concrete]]===<br />
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Ensure the Contractor places concrete as soon as possible after the excavation and reinforcement cage placement. If too much time has elapsed, loose or soft materials may accumulate at the bottom of the shaft, thus affecting the structural integrity. If this happens, direct the Contractor to remove the reinforcement cage, and remove loose or soft materials.<br />
<br />
Use lighting to inspect the reinforcement cage and side of excavation for dry method construction. Ensure loose materials and groundwater is removed prior to placement of concrete.<br />
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Inspect by probing and measuring the shaft for wet method construction. The Contractor is required to place the concrete in one continuous operation starting from the bottom of the shaft. Once concrete reaches the top of the shaft, inspect the concrete for contaminants, and direct the Contractor to continue concrete placement until good quality concrete flows over the top of the shaft. The concrete should not be vibrated. Ensure the Contractor uses a sump or channel adjacent to the shaft to transmit displaced fluid and concrete away from the shaft opening. If polymer slurry is used, ensure the Contractor collects and disposes of the drilling fluids or polymer slurry appropriately. <br />
<br />
Track the volume of concrete going into the shafts based on tickets, and perform theoretical concrete volume calculation based on the diameter and the length of the shaft. If the numbers vary by too much, it is possible a void is present.<br />
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====[[#Free Fall Concrete Placement|Free Fall Concrete Placement]]====<br />
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Free fall concrete placement can only be done in a dry shaft excavation.<br />
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The falling concrete cannot strike the sides of the excavation or the reinforcing cage. Ensure the Contractor uses a centering drop chute at least 3 feet long. If concrete strikes the sides of the excavation or the reinforcing cage, direct the Contractor to reduce the height of free fall, the rate of concrete flow, or both. The free fall height limit is 80 feet.<br />
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====[[#Tremie Tube Concrete Placement|Tremie Tube Concrete Placement]]====<br />
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Ensure the Contractor is using a tremie tube of at least 10 inches in diameter. Inspect the bottom of the Contractor’s tremie tube to ensure there is a bottom plate, valve, or plug so no water can get into the tube and contaminate the concrete prior to placement.<br />
<br />
The tremie tube must be placed at the bottom of the shaft, and once the plate or plug is removed, or valve is opened, ensure the Contractor keeps the discharge end 5 feet to 10 feet immersed in concrete before raising the tremie tube.<br />
<br />
It is ideal for the concrete to be placed continuously until complete, however, should the Contractor need to withdraw the tremie tube from the concrete, ensure the discharge end is re-sealed, charged with concrete, and inserted back into the concrete at least 10 feet before continuing with the concrete placement.<br />
<br />
For cased shafts, it is important discharge keep a head of concrete above the bottom of casing to be removed, and then remove the casing slowly, to allow the concrete to fill the annular space created by the case thickness. If the concrete level goes down during case extraction, direct the Contractor to stop the extraction, and add more concrete.<br />
<br />
The concrete must be placed in a timely fashion, so the slump does not go below 4”, as the concrete will not properly envelope the rebar cage, or fill the shaft to the required diameter. See Figure 9 for an example of concrete not filling the required shaft diameter.<br />
<br />
Allow the concrete to continue flowing at the top of the shaft, until quality concrete displaces all drilling fluid. Drilling fluid at the top of the shaft may have to be pumped of.<br />
<br />
Ensure the Contractor provides a hand floated surface finish at the top of the shaft concrete per [http://mdotcf.state.mi.us/public/specbook/files/2012/706%20Str%20Conc%20Construction.pdf subsection 706.06.M.2] of the Standard Specifications for Construction.<br />
<br />
* Do not remove the tremie tube from the concrete to take concrete QA samples.<br />
<br />
[[File:Fig 718-9.png|600px|framed|center|Figure 9. Improper concrete placement]]<br />
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====[[#Pumped Concrete Placement|Pumped Concrete Placement]]====<br />
<br />
Concrete can be pumped for by dry and wet shaft excavations, however, for use in wet excavations, ensure the Contractor provides a pump discharge tube with watertight joints.<br />
<br />
Pumped concrete is very similar to tremie concrete in terms of operations. The main issue to watch is the sway and movement of the pumping pipes during concrete placement. Ensure the Contractor guides or anchors the pumping pipes as to not disturb already placed fresh concrete.<br />
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===[[#POST CONSTRUCTION INTEGRITY TESTING|POST CONSTRUCTION INTEGRITY TESTING]]===<br />
<br />
Check the plans and specifications for any type of post construction integrity testing to be done on the completed shaft. There are several methods of non-destructive testing:<br />
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====[[#Pulse Echo Integrity Testing|Pulse Echo Integrity Testing]]====<br />
<br />
This type of test involves setting an ultrasonic transducer on the surfaces of the concrete, which send wave pulses through the material. Wave pulses will continue through solid concrete until a concrete to air interface, at which time the pulse is reflected back to the transducer, and a depth can be measured. In the presence of voids, the wave would reflect back sooner than expected given the overall thickness of the materials.<br />
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====[[#Cross Hole Sonic Logging|Cross Hole Sonic Logging]]====<br />
<br />
This type of test involves the attachment of steel access tubes to the vertical cage rebar prior to concrete placement. The concrete is then placed and allowed to cure. Immediately after concrete placement, the steel access tubes are to be filled with water to protect from concrete infiltration. After curing, a sound source and a received are lowered into the steel access tubes, and while keeping them at the same elevation, sonic pulses are emitted from the sound source, and the wave generated is picked up by the receiver. Based on the speed the wave propagates through the material, the receiver maps the integrity of the surrounding concrete, and voids are reported where the wave returns to the receiver at faster rates than sound areas.<br />
<br />
These types of tests are typically performed by a skilled technician, or MDOT prequalified consultant. The [http://www.michigan.gov/mdot/0,4616,7-151-9623_26663_27303-269622--,00.html Geotechnical Services Section] will be present during integrity testing to help analyze and interpret results.<br />
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<br />
====[[#Coring|Coring]]====<br />
<br />
Coring is a destructive test to remove cores of concrete from the finished shaft, and perform testing to determine concrete quality. Coring may also be done when voids are identified during non-destructive tests to reach the detected void. Grout can then be used to fill the void, and the core holes.<br />
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<br />
==[[#MEASUREMENT AND PAYMENT|MEASUREMENT AND PAYMENT]]==<br />
<br />
<span style="color: red"> -Reserved- </span><br />
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[[Category:Construction Manual]]<br />
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<br />
<center><span STYLE="font: 60pt arial;">'''719'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Earth Retaining Structures'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/719%20Earth%20Retaining%Structures.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 719]</center><br />
<br />
==[[#General|General]]==<br />
<br />
Below is a list with definitions of common earth retaining structures utilized by MDOT:<br />
<br />
*Abutment – A structure located at the end of a bridge span that supports the vertical loads from the bridge superstructure, and resists lateral loads from fill material on which the roadway rests immediately adjacent to the bridge.<br />
<br />
*Anchored Wall – An earth retaining system typically composed of the same elements as non-gravity cantilevered walls and that derive additional lateral resistance from one or more tiers of anchors.<br />
<br />
*Mechanically Stabilized Earth (MSE) Wall – A soil-retaining system, employing either strip or grid-type, metallic, or polymeric tensile reinforcements in the soil mass, and a facing element that is either vertical or nearly vertical.<br />
<br />
*Segmental Block Retaining Wall – A soil-retaining system, typically employing polymeric tensile reinforcements in the soil mass attached to a facing element that consists of segmental blocks. Segmental blocks are typically dry cast blocks.<br />
<br />
*Modular Block Retaining Wall – A soil-retaining system that consists of modular blocks stacked to form a gravity wall with a vertical or nearly vertical face. Modular blocks are typically large precast concrete blocks.<br />
<br />
*Non-Gravity Cantilever Retaining Wall – A soil-retaining system that derives lateral resistance through embedment of vertical wall elements and supports retained soil with facing elements. Vertical wall elements may consist of discrete elements (piles, drilled shafts, etc.) or a continuous system (sheet piles, tangent drilled shafts, etc.).<br />
<br />
*Rigid Gravity and Semi-Gravity Retaining Wall – A structure that provides lateral support for a mass of soil and that owes its stability primarily to its own weight and to the weight of any soil located directly above its base.<br />
<br />
Some of these elements may not be detailed on the plans, and may require shop drawing submittals for approval. See 707 of the MDOT Construction Manual for shop drawing requirements.<br />
<br />
==[[#Abutments|Abutments]]==<br />
<br />
MDOT utilizes the following types of abutments:<br />
<br />
*Curtainwall Abutment (see rigid-gravity retaining wall below);<br />
<br />
<br />
[[File:Fig719.png|600px|framed|center|Figure 1. Unreinforced concrete rigid-gravity wall, or curtain wall abutment]]<br />
<br />
<br />
<br />
*Cantilevered Abutment (see semi-gravity retaining wall below)<br />
<br />
<br />
[[File:Fig719-2.png|600px|framed|center|Figure 2. reinforced cantilever abutment wall]]<br />
<br />
<br />
<br />
*Integral and Semi-Integral Abutments – Integral and semi-integral abutments are detailed in the MDOT Bridge Design Guides 6.20.04, 6.20.04B, 6.20.04D.<br />
<br />
Integral abutments are designed to be supported on a single row of piles that are oriented with their webs parallel to the bridge reference line to allow weak axis bending to accommodate superstructure articulation due to thermal gradient and live loading. Splices for piles in integral abutments must be complete joint penetration (CJP). Alternative mechanical splicer channels are not permitted.<br />
<br />
==[[#Anchored Wall|Anchored Wall]]==<br />
<br />
Anchored walls can consist of ground anchors or tie backs. Verification load testing and proof load testing of the ground anchors is typically performed on all anchors to ensure the actual lateral pullout resistance is within the design tolerances. The verification load testing procedures will be detailed in the contract documents.<br />
<br />
<br />
<br />
==[[#Mechanically Stabilized Earth Wall| Mechanically Stabilized Earth Wall]]==<br />
<br />
Below are the basic components of a mechanically stabilized earth (MSE) wall system and a summary of items to review during construction:<br />
<br />
:A.Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed. Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.<br />
<br />
:B.Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office. <br />
Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.<br />
<br />
:C. Wire Facing Panels – Wire facing panels are typically specified for temporary MSE walls during Stage I construction. The walls end up being buried into the final structure and are not removed. The wire facing panels in this temporary application are usually black steel due to the short duration of use.<br />
<br />
:D. Soil Reinforcement – MDOT permits the use of steel strip-type (bar or welded wire fabric ladder) reinforcement. Soil reinforcement must be placed as close to perpendicular from the wall face as practical. The reinforcement is permitted to be skewed around piling or other obstructions, but should be done so to not only reduce the skew, but also the number of skewed reinforcement strips. Reinforcement should not be in contact with other reinforcement. For skewed reinforcement soil must be placed between overlapping reinforcement. <br />
<br />
:E. Bolts – Bolts are typically positioned with the head at the bottom side of the connection lug and the washer and nut on the top side. This allows the inspector to visually inspect that the washers and nuts have been installed as the reinforced soil is constructed behind the wall. <br />
<br />
:F. Concrete Facing Panel Joint Material – Geotextile fabric is used to prevent soil particles from moving through the concrete facing panels. If the facing panel joints start to open up then the contractor should double the geotextile over the joints in question to provide additional protection.<br />
<br />
:G. Backfill for Reinforced Soil Mass – Granular soil, typically Granular Material Class II, whic is free draining and meets the required strength and electro-chemical properties. This material must be tested and approved prior to placement.<br />
<br />
:H. Leveling Pad – Is a non-reinforced concrete pad that provides a level starting point for constructing the precast concrete facing panels. A leveling pad is not needed for a wire faced MSE wall.<br />
<br />
:I. Impervious Membrane – A polyvinylchloride (PVC) liner that prevents chloride laden runoff from penetrating into the reinforced soil mass and corroding the steel reinforcement. The liner must be shingle-lapped or seam welded and is positioned to slope away from the front of the wall and extend a minimum distance beyond the end of the soil reinforcement.<br />
<br />
:J. CIP Copings – These copings are typically used as closure pours, but can also run up to 20 feet in length and can overlap adjacent panels without the need for a bond breaker. Expansion joint material is needed when butting CIP coping up to precast coping.<br />
<br />
:K. Foundation Underdrains – Are strategically placed to transport water from the reinforced soil mass to a location far away from the wall. MSE walls are generally not designed for hydrostatic pressure. Foundation underdrains are to be installed at the locations indicated on the plans. The lower foundation underdrains are to be located as low as possible but still drain to either a ditch or a drainage structure.<br />
<br />
MSE Wall Construction Considerations<br />
<br />
*During the wet cure for the concrete bridge deck the water coming off of the deck needs to be collected and discharged away from the MSE wall. Water runoff from the deck may saturate the MSE backfill and cause wall movement.<br />
<br />
*Groundwater needs to be controlled to prevent hydrostatic forces from acting on the wall. If groundwater is encountered during construction the location/number of foundation underdrains may need to be reevaluated.<br />
<br />
*Compaction of the Select Backfill and any subgrade undercuts is important in order to limit any future settlement of the MSE wall fill.<br />
<br />
[[File:Fig 719-3.png|600px|framed|center|Figure 1. MSE wall]]<br />
<br />
==[[#Non-Gravity Cantilevered Retaining Wall| Non-Gravity Cantilevered Retaining Wall]]==<br />
<br />
Examples of on-gravity cantilevered retaining walls are listed below:<br />
*Tangent piles or drilled shafts;<br />
*Drilled shafts or auger-cast piles spanned by structural facing (lagging, panels or shotcrete);<br />
*Steel sheet piling (see Section 704 – Steel Sheet Piling and Cofferdams).<br />
<br />
==[[#Rigid-Gravity and Semi-Gravity Retaining Wall|Rigid-Gravity and Semi-Gravity Retaining Wall]]==<br />
<br />
[[File:Fig719-4.png|600px|framed|center|Figure 3. Reinforced concrete counterfort semi-gravity wall]]<br />
<br />
<br />
<br />
[[File:Fig719-5.png|600px|framed|center|Figure 4. Reinforced concrete cantilever semi-gravity wall.]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=File:Fig719-5.png&diff=3886File:Fig719-5.png2014-11-12T19:32:39Z<p>HarrisR18: </p>
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<div></div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=File:Fig719-4.png&diff=3885File:Fig719-4.png2014-11-12T19:32:01Z<p>HarrisR18: </p>
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<div></div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=File:Fig719-3.png&diff=3884File:Fig719-3.png2014-11-12T19:31:26Z<p>HarrisR18: </p>
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<div></div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=File:Fig719-2.png&diff=3883File:Fig719-2.png2014-11-12T19:30:44Z<p>HarrisR18: </p>
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<div></div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=File:Fig719-1.png&diff=3882File:Fig719-1.png2014-11-12T19:30:15Z<p>HarrisR18: </p>
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<div></div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=718_-_Drilled_Shafts&diff=3881718 - Drilled Shafts2014-11-12T19:26:56Z<p>HarrisR18: /* Abutments */</p>
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<div><br />
<center><span STYLE="font: 60pt arial;">'''718'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Drilled Shafts'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 718]</center><br />
<br />
<br />
==[[#GENERAL|GENERAL]]==<br />
<br />
Drilled shaft foundations are also referred to caissons, drilled piers, or bored piles, and consist of circular shafts of varying diameter, drilled to a design depth, reinforced with a steel rebar cage, and filled with concrete. Drilled shaft foundations can support large loads, and are used when driving steel piles is not feasible, or surrounding structures or utilities are too sensitive to survive the vibrations from steel foundation pile driving operations. Like steel foundation piles, loads from the superstructure transfer into the drilled shafts, which transfer loads to soil layers through side friction, end bearing, or a combination of the two. Drilled shafts are used for bridge foundations, and other ancillary structure foundations such as sign cantilevers and trusses, and signal strain poles.<br />
<br />
Drilled shafts can be constructed in the dry, or in the wet, and can also include a steel casing.<br />
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<br />
===[[#DRY CONSTRUCTION METHOD|DRY CONSTRUCTION METHOD]]===<br />
<br />
Dry construction methods are generally used when the water table is below the bottom of the shaft, and the existing soils are stiff enough as not to sloughing or caving into the hole during drilling operations. Any accumulated water greater than 3 inches at the bottom of the shaft must be pumped out prior to rebar and concrete placement, and during concrete placement, water cannot flow into the shaft at a rate greater than 12 inches within 1 hour.<br />
<br />
Typical issues with dry construction methods are if the soils are unstable, or the water table is too high, but the Contractor attempts to force dry shaft construction. In this scenario, soil caving problems will lead to soil inclusions in the shaft concrete, affecting the shaft integrity. If any problems like this arise during construction, contact the Geotechnical Services area.<br />
<br />
Another issue to watch for is if the Contractor leaves the excavation open for too long prior to reinforcement cage and concrete placement. Soils that were capable of maintaining hole stability during the drilling operations may shrink or swell over time and slowly lose that ability, resulting in caving leading to soil inclusions in the shaft concrete affecting the shaft integrity.<br />
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===[[#WET CONSTRUCTION METHOD|WET CONSTRUCTION METHOD]]===<br />
<br />
Wets construction methods are generally used where a dry excavation cannot be maintained during drilling, or shaft concrete placement. This typically occurs in areas of high water tables, and sandy soils that would otherwise slough or cave into the shaft during drilling operations. Water or a polymer slurry is used to contain water seepage, and maintain stability of the shaft excavation. Polymer slurry must be de-sanded and cleaned if used. Temporary surface casings are typically used to ensure shaft alignment. The rebar cage is lowered into the shaft, and concrete is placed using a tremie tube, or concrete pump capable of reaching the bottom of the shaft.<br />
<br />
Typical issues with wet construction methods are inexperienced Contractors that do not understand the mechanics of polymer slurry construction, and the need to ensure proper suspension of sediment and cuttings for removal, and control of caving. This can lead to shafts not being properly cleaned of sediment, resulting in voids, or inclusions in the concrete, affecting the shaft integrity.<br />
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===[[#DRY TEMPORARY CASING METHOD|DRY TEMPORARY CASING METHOD]]===<br />
<br />
Dry temporary cased construction methods are generally used where caving soils occur, over soil or rock deformations are expected, but the casing can maintain a dry and stable excavation. The casing is advanced simultaneously with the excavation. After placement of the rebar cage, the casing is then withdrawn slowly during concrete placement until removed at the top of shaft.<br />
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===[[#WET TEMPORARY CASING METHOD|WET TEMPORARY CASING METHOD]]===<br />
<br />
Wet temporary cased construction methods are generally used where caving soils occur, and a dry excavation cannot be maintained, the soils are too permeable, and the groundwater is higher than the bottom of the shaft. The casing is advanced simultaneously with the excavation, but it is important that no drilling occur outside the casing through any caving soil layers. After placement of the rebar cage, the concrete is placed using a tremie tube or concrete pump capable of reaching the bottom of the shaft. The water in the casing is not to be pumped out, rather it is to be displaced by the concrete placement.<br />
<br />
It is important to ensure the Contractor maintains a positive fluid pressure head in the shaft above the ground water elevation, or material from the side walls of the shaft will be pulled into the bottom of the shaft.<br />
<br />
For both the wet and dry casing methods, the casing is typically installed in a telescoping fashion, where the top casings may be larger than the drilled shaft diameter as called for on the plans. The depth of the hole will also dictate how many sections of casing are to be used. Ensure the contractor does not telescope the casings down to a diameter less than the design diameter as shown on the plans.<br />
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<br />
==[[#MATERIALS|MATERIALS]]==<br />
<br />
===[[#Concrete, Grade S2, and Grade T|Concrete, Grade S2, and Grade T]]===<br />
<br />
Ensure concrete materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf section 701] of the Standard Specifications for Construction, except modifications for the slump requirements per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction. Concrete Grade S2 is to be used for dry construction, and Concrete Grade T is to be used for wet construction.<br />
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<br />
===[[#Steel Reinforcement|Steel Reinforcement]]===<br />
<br />
Ensure steel reinforcement bars are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/905%20Steel%20Reinforcement.pdf section 905] of the Standard Specifications for Construction. Check the plans and specifications for epoxy rebar requirements.<br />
<br />
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<br />
===[[#Steel Casing|Steel Casing]]===<br />
<br />
Ensure steel casing materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/919%20Perm%20Traf%20Signs,%20Supports.pdf section 919.10] of the Standard Specifications for Construction. Permanent casing will also require Buy America certification, temporary casings will not, unless left in place.<br />
<br />
Review the plans for temporary casing-left in place cut off elevations. The Contractor is required to provide casing to be smooth and watertight, and capable of withstanding the pressure of concrete and the lateral earth pressures exerted down the length of the shaft. Ensure the outside diameter of the casing is at least equal to the diameter of the shaft as called for on the plans.<br />
<br />
Temporary casings should come equipped with hook holes, or other attachments to aid in the removal as the concrete pour advances. The concrete placement is to be complete prior to complete removal of the casing. The casings should be removed slowly, and with pull forces being in line with the shaft axis. Do not allow the contractor to pull shaft casings with equipment offset from the centerline of the shaft, as this will either disrupt the already placed concrete, or case caving of soil materials into the plastic concrete.<br />
<br />
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<br />
===[[#Polymer slurry|Polymer slurry]]===<br />
<br />
When wet construction methods are required, polymer type slurry is required. Bentonite slurry is prohibited. Ensure the polymer slurry is of sufficient specific gravity to ensure stability of the excavation during drilling operations, and allows for concrete placement. The Geotechnical Services area will typically review and approve the Contractor’s proposed polymer slurry materials.<br />
<br />
Ensure any polymer slurry used meets the requirements of [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Table 718-1] from the Standard Specifications for Construction. Ensure the Contractor maintains the height of polymer slurry to prevent the side walls of the excavation from caving, and the bottom from heaving.<br />
<br />
Ensure the contractor pre-mixes the polymer slurry materials with clean, fresh water, and allow time for hydration prior to pumping into shaft excavation. The polymer slurry should be agitated to prevent setting up in the shaft.<br />
<br />
If de-sanding is required, ensure the Contractor provides the appropriate equipment. Prior to placement of shaft concrete, take polymer slurry samples with a polymer slurry test kit to determine if heavily contaminated polymer slurry at the bottom of the shaft is to be removed. Ensure the Contractor controls and collects polymer slurry exiting the excavation as the concrete displaces the volume. Review the plans for polymer slurry handling and disposal requirements.<br />
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<br />
==[[#CONSTRUCTION|CONSTRUCTION]]==<br />
<br />
===[[#EQUIPMENT|Equipment]]===<br />
<br />
Ensure the contractor is using appropriate equipment to drill the shafts given the site conditions reported in the soil borings, and geotechnical subsurface exploration report. See Figure 1 for a typical drill rig set up. The major components of drill rig include:<br />
<br />
* Crawler or truck mounted auger<br />
* Auger of the appropriate type – rock auger, single or double flight earth auger. See Figure 2 for a double flight earth auger, see Figure 3 for a single flight rock auger.<br />
* Muck or clean out bucket – see Figures 4 and 5 for a muck bucket example.<br />
* Rock core barrel – see Figure 6 for a rock core barrel example.<br />
[[File:Fig 718-1.png|600px|framed|center|Figure 1. Typical drill rig set up]]<br />
<br />
[[File:Fig 718-2.png|600px|framed|center|Figure 2. Double flight earth auger]]<br />
<br />
[[File:Fig 718-3.png|600px|framed|center|Figure 3. Single flight rock auger]]<br />
<br />
[[File:Fig 718-4.png|600px|framed|center|Figure 4. Muck bucket]]<br />
<br />
[[File:Fig 718-5.png|600px|framed|center|Figure 5. Muck bucket bottom]]<br />
<br />
[[File:Fig 718-6.png|600px|framed|center|Figure 6. Soft rock core barrel]]<br />
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<br />
===[[#DRILLED SHAFT CONSTRUCTION|DRILLED SHAFT CONSTRUCTION]]===<br />
To track drilled shaft operations, use MDOT [http://mdotcf.state.mi.us/public/webforms/public/1988.pdf form 1988] – DRILLED SHAFT INSPECTION RECORD FOR HIGHWAY SIGNS, LUMINAIRES, AND TRAFFIC SIGNALS.<br />
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<br />
====[[#Prior to Drilled Shaft Operations|Prior to Drilled Shaft Operations]]====<br />
<br />
The Contractor is required to submit a Drilled Shaft Installation plan, per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.A] of the Standard Specifications for Construction. This plan is to detail all equipment to be used, the construction sequence, rebar and concrete placement, etc. The Geotechnical Services area will review and approve the Drilled Shaft Installation plan. Review and understand the following:<br />
<br />
* Proposed equipment, including cranes, drills, augers, core barrels, bailing buckets, cleaning equipment, polymer slurry pumps and cleaning equipment, tremie tubes or concrete pumps, and casing.<br />
<br />
* Construction sequence, including methods to ensure a stable excavation, and removal of materials at the bottom of the shaft prior to rebar cage placement.<br />
<br />
* Shaft excavation methods, including proposed excavation methods through supporting and caving soil layers.<br />
<br />
* Method to mix, circulate and de-sand polymer slurry for wet construction methods.<br />
<br />
* Reinforcement placement, including support and centering methods.<br />
<br />
* Concrete placement, including free fall, tremie, or concrete pumping procedures.<br />
<br />
* Methods to prevent drilled shaft excavation spoils from entering waterways, wetlands and floodplains.<br />
<br />
* Fall protection plan conforming to MIOSHA Construction Safety Standards, including a rescue plan for shafts with a diameter of at least 30 inches, and at least 6 feet deep. This must be in place prior to commencement of any drilling operations.<br />
<br />
* Conformance with shaft diameter and rebar requirements based on details shown in the plans.<br />
<br />
Ensure the Contractor has brought all of the proposed equipment as stated in their approved Drilled Shaft Installation plan.<br />
<br />
If the shaft is to be constructed during the wet method, verify if the Contractor is allowed to use water as the drilling fluid, or if polymer slurry is required. Typically, Contractors will want to use water, but water will not prevent caving in deeper shafts. The use of bentonite slurry is prohibited.<br />
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<br />
====[[#During Drilling Operations|During Drilling Operations]]====<br />
<br />
Ensure the Contractor performs the following:<br />
<br />
* Check the drilled shaft dimensions and the alignment with reference stakes and plumb bob.<br />
<br />
* Check the dimensions and alignment of the casing inserted in the excavation.<br />
<br />
* Insert a rigid rod assembly with several 90-degree offsets equal to the shaft diameter into the shaft excavation to ensure required diameter.<br />
<br />
* Construction Method Log: The Contractor is required to submit a daily construction method log during drilled shaft excavation and construction per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.5] of the Standard Specifications for Construction. Ensure the following information is shown on the logs:<br />
<br />
* Start dates and completions dates<br />
<br />
* Drilled shaft identification number<br />
<br />
* Location<br />
<br />
* Actual top and bottom elevation of drilled shaft <br />
<br />
* Shaft diameter<br />
<br />
* Final centerline location at top of shaft<br />
<br />
* Variation of drilled shaft from plumb<br />
<br />
* Top and bottom elevation of any permanent casing<br />
<br />
* Description of each soil and rock material encountered during excavating and the top and bottom depths or elevations<br />
<br />
* Depth drilled into bearing stratum<br />
<br />
* Top and bottom elevations of obstructions encountered<br />
<br />
* Amount of obstruction time<br />
<br />
* Depth or elevation of encountered seepage of groundwater<br />
<br />
* Actual volume of concrete placed, compared to the theoretical concrete volume to detect any large void or intrusions of extraneous materials<br />
<br />
* Any remarks to better describe operations.<br />
<br />
Ensure the Contractor maintains the required drilling fluid or polymer slurry levels to prevent caving.<br />
<br />
Construction tolerances – Ensure the drilled shafts are within 3 inches horizontally of centerlines shown on the plans, and the drilled shaft is no more than 1 percent out of plumb, as measured horizontally from the actual center of the shaft at the shaft design top elevation.<br />
<br />
Ensure the Contractor cleans each shaft so at least 50% of the base contains less than ½ inch of sediment. The shaft bottom should have no more than 1 ½ inches of debris above the required bottom elevation. Use a weighted tape to check the bottom of the shaft excavation for debris.<br />
<br />
Marks on the Kelly Bar should be checked to ensure the required bottom of shaft elevation. Monitor the excavation to ensure the expected amount of materials are removed by the auger, if not, caving soils are present.<br />
<br />
Ensure the top elevation of the drilled shaft is from +1 inch to -3 inches from the top of the shaft elevation shown on the plans. For shafts outside of this tolerance range, contact the Geotechnical Services area for recommendations as to corrections. [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Subsection 718.03.C.4] of the Standard Specifications for Construction dictates contractual obligations of the contractor to correct out of tolerance shafts.<br />
<br />
Verify the soil cuttings as they are removed from the auger, and notify the Geotechnical Services area if soil cuttings appear different than those shown on the soil borings. Ensure the Contractor stores soil cuttings away from the drill shaft locations.<br />
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===[[#Obstruction Removal|Obstruction Removal]]===<br />
<br />
Obstructions are to be removed per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.F.2] of the Standard Specifications for Construction. Obstructions may include old concrete foundations, abandoned utilities, or boulders and cobbles. Ensure the Contractor uses tools and procedures as approved by the Geotechnical Services Section to remove the obstructions. Special procedures and tools include:<br />
<br />
* Chisels<br />
* Boulder breakers<br />
* Core barrels<br />
* Air tools<br />
* Hand excavation<br />
* Temporary casing<br />
* Enlarging the drilled shaft diameter<br />
<br />
Removal of obstructions that require special equipment or tools will be measured and paid for as extra work per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.04.D] of the Standard Specifications or Construction. A budget amount will be established to pay for removing obstructions. If the Contractor and the Engineer cannot agree on a lump sum price, the Engineer will direct the work to be done on a force account basis.<br />
<br />
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<br />
===[[#Placing Steel Reinforcement|Placing Steel Reinforcement]]===<br />
<br />
Check the plans and specifications to verify the Contractor is using the correct size longitudinal bars and lateral or spiral reinforcement, and correct bar lap lengths if used.<br />
<br />
Reinforcing cage – maintain the top of the reinforcing steel cage no greater than 1 inch above, and no greater than 3 inches below the required position. Measure the distance between the top of shaft and the top of reinforcing cage with a straight edge, and direct the Contractor to correct the position if out of tolerance.<br />
<br />
Ensure the Contractor provides a fully assembled steel reinforcement cage for inspection at least two working days before the start of construction. Ensure all longitudinal bars and lateral or spiral reinforcement is properly tied. Ensure plastic spacers are tied at the quarter points around the cage perimeter, but no greater than 30 inches apart.<br />
<br />
Ensure the plastic spacers are spaced at intervals no greater than 5 feet along the length of the cage for #8 bar or smaller, and 10’ for bars larger than #8 to ensure a minimum annular space of 3 inches between the outside of the cage and the side of the excavation or casing. See Figure 7 for an example of plastic spacers on the rebar cage.<br />
<br />
[[File:Fig 718-7.png|600px|framed|center|Figure 7. Rebar cage spacers]]<br />
<br />
Ensure the Contractor does not use concrete blocks, wood blocks, or metal chairs as spacers, as these will not retain the required spacing, and will shift out of position during cage lowering, or during the concrete pour.<br />
<br />
The Contractor may use concrete blocks at the bottom of the shaft to maintain concrete cover over the reinforcement. Ensure the Contractor picks and lowers the reinforcement cage into the shaft in a controlled manner, as not to cause racking or distorting of the tied cage. See Figure 8 for a typical reinforcement cage being lowered into the completed shaft.<br />
<br />
[[File:Fig 718-8.png|600px|framed|center|Figure 8. Rebar cage being lowered into complete shaft]]<br />
<br />
Ensure the Contractor holds down the cage to control vertical displacement during concrete placement or casing extraction.<br />
<br />
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<br />
===[[#Placing Concrete|Placing Concrete]]===<br />
<br />
Ensure the Contractor places concrete as soon as possible after the excavation and reinforcement cage placement. If too much time has elapsed, loose or soft materials may accumulate at the bottom of the shaft, thus affecting the structural integrity. If this happens, direct the Contractor to remove the reinforcement cage, and remove loose or soft materials.<br />
<br />
Use lighting to inspect the reinforcement cage and side of excavation for dry method construction. Ensure loose materials and groundwater is removed prior to placement of concrete.<br />
<br />
Inspect by probing and measuring the shaft for wet method construction. The Contractor is required to place the concrete in one continuous operation starting from the bottom of the shaft. Once concrete reaches the top of the shaft, inspect the concrete for contaminants, and direct the Contractor to continue concrete placement until good quality concrete flows over the top of the shaft. The concrete should not be vibrated. Ensure the Contractor uses a sump or channel adjacent to the shaft to transmit displaced fluid and concrete away from the shaft opening. If polymer slurry is used, ensure the Contractor collects and disposes of the drilling fluids or polymer slurry appropriately. <br />
<br />
Track the volume of concrete going into the shafts based on tickets, and perform theoretical concrete volume calculation based on the diameter and the length of the shaft. If the numbers vary by too much, it is possible a void is present.<br />
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<br />
====[[#Free Fall Concrete Placement|Free Fall Concrete Placement]]====<br />
<br />
Free fall concrete placement can only be done in a dry shaft excavation.<br />
<br />
The falling concrete cannot strike the sides of the excavation or the reinforcing cage. Ensure the Contractor uses a centering drop chute at least 3 feet long. If concrete strikes the sides of the excavation or the reinforcing cage, direct the Contractor to reduce the height of free fall, the rate of concrete flow, or both. The free fall height limit is 80 feet.<br />
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<br />
====[[#Tremie Tube Concrete Placement|Tremie Tube Concrete Placement]]====<br />
<br />
Ensure the Contractor is using a tremie tube of at least 10 inches in diameter. Inspect the bottom of the Contractor’s tremie tube to ensure there is a bottom plate, valve, or plug so no water can get into the tube and contaminate the concrete prior to placement.<br />
<br />
The tremie tube must be placed at the bottom of the shaft, and once the plate or plug is removed, or valve is opened, ensure the Contractor keeps the discharge end 5 feet to 10 feet immersed in concrete before raising the tremie tube.<br />
<br />
It is ideal for the concrete to be placed continuously until complete, however, should the Contractor need to withdraw the tremie tube from the concrete, ensure the discharge end is re-sealed, charged with concrete, and inserted back into the concrete at least 10 feet before continuing with the concrete placement.<br />
<br />
For cased shafts, it is important discharge keep a head of concrete above the bottom of casing to be removed, and then remove the casing slowly, to allow the concrete to fill the annular space created by the case thickness. If the concrete level goes down during case extraction, direct the Contractor to stop the extraction, and add more concrete.<br />
<br />
The concrete must be placed in a timely fashion, so the slump does not go below 4”, as the concrete will not properly envelope the rebar cage, or fill the shaft to the required diameter. See Figure 9 for an example of concrete not filling the required shaft diameter.<br />
<br />
Allow the concrete to continue flowing at the top of the shaft, until quality concrete displaces all drilling fluid. Drilling fluid at the top of the shaft may have to be pumped of.<br />
<br />
Ensure the Contractor provides a hand floated surface finish at the top of the shaft concrete per [http://mdotcf.state.mi.us/public/specbook/files/2012/706%20Str%20Conc%20Construction.pdf subsection 706.06.M.2] of the Standard Specifications for Construction.<br />
<br />
* Do not remove the tremie tube from the concrete to take concrete QA samples.<br />
<br />
[[File:Fig 718-9.png|600px|framed|center|Figure 9. Improper concrete placement]]<br />
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<br />
====[[#Pumped Concrete Placement|Pumped Concrete Placement]]====<br />
<br />
Concrete can be pumped for by dry and wet shaft excavations, however, for use in wet excavations, ensure the Contractor provides a pump discharge tube with watertight joints.<br />
<br />
Pumped concrete is very similar to tremie concrete in terms of operations. The main issue to watch is the sway and movement of the pumping pipes during concrete placement. Ensure the Contractor guides or anchors the pumping pipes as to not disturb already placed fresh concrete.<br />
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<br />
===[[#POST CONSTRUCTION INTEGRITY TESTING|POST CONSTRUCTION INTEGRITY TESTING]]===<br />
<br />
Check the plans and specifications for any type of post construction integrity testing to be done on the completed shaft. There are several methods of non-destructive testing:<br />
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<br />
====[[#Pulse Echo Integrity Testing|Pulse Echo Integrity Testing]]====<br />
<br />
This type of test involves setting an ultrasonic transducer on the surfaces of the concrete, which send wave pulses through the material. Wave pulses will continue through solid concrete until a concrete to air interface, at which time the pulse is reflected back to the transducer, and a depth can be measured. In the presence of voids, the wave would reflect back sooner than expected given the overall thickness of the materials.<br />
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<br />
====[[#Cross Hole Sonic Logging|Cross Hole Sonic Logging]]====<br />
<br />
This type of test involves the attachment of steel access tubes to the vertical cage rebar prior to concrete placement. The concrete is then placed and allowed to cure. Immediately after concrete placement, the steel access tubes are to be filled with water to protect from concrete infiltration. After curing, a sound source and a received are lowered into the steel access tubes, and while keeping them at the same elevation, sonic pulses are emitted from the sound source, and the wave generated is picked up by the receiver. Based on the speed the wave propagates through the material, the receiver maps the integrity of the surrounding concrete, and voids are reported where the wave returns to the receiver at faster rates than sound areas.<br />
<br />
These types of tests are typically performed by a skilled technician, or MDOT prequalified consultant. The [http://www.michigan.gov/mdot/0,4616,7-151-9623_26663_27303-269622--,00.html Geotechnical Services Section] will be present during integrity testing to help analyze and interpret results.<br />
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<br />
====[[#Coring|Coring]]====<br />
<br />
Coring is a destructive test to remove cores of concrete from the finished shaft, and perform testing to determine concrete quality. Coring may also be done when voids are identified during non-destructive tests to reach the detected void. Grout can then be used to fill the void, and the core holes.<br />
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<br />
==[[#MEASUREMENT AND PAYMENT|MEASUREMENT AND PAYMENT]]==<br />
<br />
<span style="color: red"> -Reserved- </span><br />
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<br />
[[Category:Construction Manual]]<br />
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<br />
<center><span STYLE="font: 60pt arial;">'''719'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Earth Retaining Structures'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/719%20Earth%20Retaining%Structures.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 719]</center><br />
<br />
==[[#General|General]]==<br />
<br />
Below is a list with definitions of common earth retaining structures utilized by MDOT:<br />
<br />
*Abutment – A structure located at the end of a bridge span that supports the vertical loads from the bridge superstructure, and resists lateral loads from fill material on which the roadway rests immediately adjacent to the bridge.<br />
<br />
*Anchored Wall – An earth retaining system typically composed of the same elements as non-gravity cantilevered walls and that derive additional lateral resistance from one or more tiers of anchors.<br />
<br />
*Mechanically Stabilized Earth (MSE) Wall – A soil-retaining system, employing either strip or grid-type, metallic, or polymeric tensile reinforcements in the soil mass, and a facing element that is either vertical or nearly vertical.<br />
<br />
*Segmental Block Retaining Wall – A soil-retaining system, typically employing polymeric tensile reinforcements in the soil mass attached to a facing element that consists of segmental blocks. Segmental blocks are typically dry cast blocks.<br />
<br />
*Modular Block Retaining Wall – A soil-retaining system that consists of modular blocks stacked to form a gravity wall with a vertical or nearly vertical face. Modular blocks are typically large precast concrete blocks.<br />
<br />
*Non-Gravity Cantilever Retaining Wall – A soil-retaining system that derives lateral resistance through embedment of vertical wall elements and supports retained soil with facing elements. Vertical wall elements may consist of discrete elements (piles, drilled shafts, etc.) or a continuous system (sheet piles, tangent drilled shafts, etc.).<br />
<br />
*Rigid Gravity and Semi-Gravity Retaining Wall – A structure that provides lateral support for a mass of soil and that owes its stability primarily to its own weight and to the weight of any soil located directly above its base.<br />
<br />
Some of these elements may not be detailed on the plans, and may require shop drawing submittals for approval. See 707 of the MDOT Construction Manual for shop drawing requirements.<br />
<br />
==[[#Abutments|Abutments]]==<br />
<br />
MDOT utilizes the following types of abutments:<br />
<br />
*Curtainwall Abutment (see rigid-gravity retaining wall below);<br />
<br />
<br />
[[File:Fig 719.png|600px|framed|center|Figure 1. Unreinforced concrete rigid-gravity wall, or curtain wall abutment]]<br />
<br />
<br />
<br />
*Cantilevered Abutment (see semi-gravity retaining wall below)<br />
<br />
<br />
[[File:Fig 719-2.png|600px|framed|center|Figure 2. reinforced cantilever abutment wall]]<br />
<br />
<br />
<br />
*Integral and Semi-Integral Abutments – Integral and semi-integral abutments are detailed in the MDOT Bridge Design Guides 6.20.04, 6.20.04B, 6.20.04D.<br />
<br />
Integral abutments are designed to be supported on a single row of piles that are oriented with their webs parallel to the bridge reference line to allow weak axis bending to accommodate superstructure articulation due to thermal gradient and live loading. Splices for piles in integral abutments must be complete joint penetration (CJP). Alternative mechanical splicer channels are not permitted.<br />
<br />
==[[#Anchored Wall|Anchored Wall]]==<br />
<br />
Anchored walls can consist of ground anchors or tie backs. Verification load testing and proof load testing of the ground anchors is typically performed on all anchors to ensure the actual lateral pullout resistance is within the design tolerances. The verification load testing procedures will be detailed in the contract documents.<br />
<br />
<br />
<br />
==[[#Mechanically Stabilized Earth Wall| Mechanically Stabilized Earth Wall]]==<br />
<br />
Below are the basic components of a mechanically stabilized earth (MSE) wall system and a summary of items to review during construction:<br />
<br />
:A.Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed. Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.<br />
<br />
:B.Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office. <br />
Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.<br />
<br />
:C. Wire Facing Panels – Wire facing panels are typically specified for temporary MSE walls during Stage I construction. The walls end up being buried into the final structure and are not removed. The wire facing panels in this temporary application are usually black steel due to the short duration of use.<br />
<br />
:D. Soil Reinforcement – MDOT permits the use of steel strip-type (bar or welded wire fabric ladder) reinforcement. Soil reinforcement must be placed as close to perpendicular from the wall face as practical. The reinforcement is permitted to be skewed around piling or other obstructions, but should be done so to not only reduce the skew, but also the number of skewed reinforcement strips. Reinforcement should not be in contact with other reinforcement. For skewed reinforcement soil must be placed between overlapping reinforcement. <br />
<br />
:E. Bolts – Bolts are typically positioned with the head at the bottom side of the connection lug and the washer and nut on the top side. This allows the inspector to visually inspect that the washers and nuts have been installed as the reinforced soil is constructed behind the wall. <br />
<br />
:F. Concrete Facing Panel Joint Material – Geotextile fabric is used to prevent soil particles from moving through the concrete facing panels. If the facing panel joints start to open up then the contractor should double the geotextile over the joints in question to provide additional protection.<br />
<br />
:G. Backfill for Reinforced Soil Mass – Granular soil, typically Granular Material Class II, whic is free draining and meets the required strength and electro-chemical properties. This material must be tested and approved prior to placement.<br />
<br />
:H. Leveling Pad – Is a non-reinforced concrete pad that provides a level starting point for constructing the precast concrete facing panels. A leveling pad is not needed for a wire faced MSE wall.<br />
<br />
:I. Impervious Membrane – A polyvinylchloride (PVC) liner that prevents chloride laden runoff from penetrating into the reinforced soil mass and corroding the steel reinforcement. The liner must be shingle-lapped or seam welded and is positioned to slope away from the front of the wall and extend a minimum distance beyond the end of the soil reinforcement.<br />
<br />
:J. CIP Copings – These copings are typically used as closure pours, but can also run up to 20 feet in length and can overlap adjacent panels without the need for a bond breaker. Expansion joint material is needed when butting CIP coping up to precast coping.<br />
<br />
:K. Foundation Underdrains – Are strategically placed to transport water from the reinforced soil mass to a location far away from the wall. MSE walls are generally not designed for hydrostatic pressure. Foundation underdrains are to be installed at the locations indicated on the plans. The lower foundation underdrains are to be located as low as possible but still drain to either a ditch or a drainage structure.<br />
<br />
MSE Wall Construction Considerations<br />
<br />
*During the wet cure for the concrete bridge deck the water coming off of the deck needs to be collected and discharged away from the MSE wall. Water runoff from the deck may saturate the MSE backfill and cause wall movement.<br />
<br />
*Groundwater needs to be controlled to prevent hydrostatic forces from acting on the wall. If groundwater is encountered during construction the location/number of foundation underdrains may need to be reevaluated.<br />
<br />
*Compaction of the Select Backfill and any subgrade undercuts is important in order to limit any future settlement of the MSE wall fill.<br />
<br />
[[File:Fig 719-3.png|600px|framed|center|Figure 1. MSE wall]]<br />
<br />
==[[#Non-Gravity Cantilevered Retaining Wall| Non-Gravity Cantilevered Retaining Wall]]==<br />
<br />
Examples of on-gravity cantilevered retaining walls are listed below:<br />
*Tangent piles or drilled shafts;<br />
*Drilled shafts or auger-cast piles spanned by structural facing (lagging, panels or shotcrete);<br />
*Steel sheet piling (see Section 704 – Steel Sheet Piling and Cofferdams).<br />
<br />
==[[#Rigid-Gravity and Semi-Gravity Retaining Wall|Rigid-Gravity and Semi-Gravity Retaining Wall]]==<br />
<br />
[[File:Fig719-4.png|600px|framed|center|Figure 3. Reinforced concrete counterfort semi-gravity wall]]<br />
<br />
<br />
<br />
[[File:Fig719-5.png|600px|framed|center|Figure 4. Reinforced concrete cantilever semi-gravity wall.]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=718_-_Drilled_Shafts&diff=3880718 - Drilled Shafts2014-11-12T19:25:44Z<p>HarrisR18: /* Mechanically Stabilized Earth Wall */</p>
<hr />
<div><br />
<center><span STYLE="font: 60pt arial;">'''718'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Drilled Shafts'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 718]</center><br />
<br />
<br />
==[[#GENERAL|GENERAL]]==<br />
<br />
Drilled shaft foundations are also referred to caissons, drilled piers, or bored piles, and consist of circular shafts of varying diameter, drilled to a design depth, reinforced with a steel rebar cage, and filled with concrete. Drilled shaft foundations can support large loads, and are used when driving steel piles is not feasible, or surrounding structures or utilities are too sensitive to survive the vibrations from steel foundation pile driving operations. Like steel foundation piles, loads from the superstructure transfer into the drilled shafts, which transfer loads to soil layers through side friction, end bearing, or a combination of the two. Drilled shafts are used for bridge foundations, and other ancillary structure foundations such as sign cantilevers and trusses, and signal strain poles.<br />
<br />
Drilled shafts can be constructed in the dry, or in the wet, and can also include a steel casing.<br />
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<br />
===[[#DRY CONSTRUCTION METHOD|DRY CONSTRUCTION METHOD]]===<br />
<br />
Dry construction methods are generally used when the water table is below the bottom of the shaft, and the existing soils are stiff enough as not to sloughing or caving into the hole during drilling operations. Any accumulated water greater than 3 inches at the bottom of the shaft must be pumped out prior to rebar and concrete placement, and during concrete placement, water cannot flow into the shaft at a rate greater than 12 inches within 1 hour.<br />
<br />
Typical issues with dry construction methods are if the soils are unstable, or the water table is too high, but the Contractor attempts to force dry shaft construction. In this scenario, soil caving problems will lead to soil inclusions in the shaft concrete, affecting the shaft integrity. If any problems like this arise during construction, contact the Geotechnical Services area.<br />
<br />
Another issue to watch for is if the Contractor leaves the excavation open for too long prior to reinforcement cage and concrete placement. Soils that were capable of maintaining hole stability during the drilling operations may shrink or swell over time and slowly lose that ability, resulting in caving leading to soil inclusions in the shaft concrete affecting the shaft integrity.<br />
<br />
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<br />
===[[#WET CONSTRUCTION METHOD|WET CONSTRUCTION METHOD]]===<br />
<br />
Wets construction methods are generally used where a dry excavation cannot be maintained during drilling, or shaft concrete placement. This typically occurs in areas of high water tables, and sandy soils that would otherwise slough or cave into the shaft during drilling operations. Water or a polymer slurry is used to contain water seepage, and maintain stability of the shaft excavation. Polymer slurry must be de-sanded and cleaned if used. Temporary surface casings are typically used to ensure shaft alignment. The rebar cage is lowered into the shaft, and concrete is placed using a tremie tube, or concrete pump capable of reaching the bottom of the shaft.<br />
<br />
Typical issues with wet construction methods are inexperienced Contractors that do not understand the mechanics of polymer slurry construction, and the need to ensure proper suspension of sediment and cuttings for removal, and control of caving. This can lead to shafts not being properly cleaned of sediment, resulting in voids, or inclusions in the concrete, affecting the shaft integrity.<br />
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<br />
===[[#DRY TEMPORARY CASING METHOD|DRY TEMPORARY CASING METHOD]]===<br />
<br />
Dry temporary cased construction methods are generally used where caving soils occur, over soil or rock deformations are expected, but the casing can maintain a dry and stable excavation. The casing is advanced simultaneously with the excavation. After placement of the rebar cage, the casing is then withdrawn slowly during concrete placement until removed at the top of shaft.<br />
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<br />
===[[#WET TEMPORARY CASING METHOD|WET TEMPORARY CASING METHOD]]===<br />
<br />
Wet temporary cased construction methods are generally used where caving soils occur, and a dry excavation cannot be maintained, the soils are too permeable, and the groundwater is higher than the bottom of the shaft. The casing is advanced simultaneously with the excavation, but it is important that no drilling occur outside the casing through any caving soil layers. After placement of the rebar cage, the concrete is placed using a tremie tube or concrete pump capable of reaching the bottom of the shaft. The water in the casing is not to be pumped out, rather it is to be displaced by the concrete placement.<br />
<br />
It is important to ensure the Contractor maintains a positive fluid pressure head in the shaft above the ground water elevation, or material from the side walls of the shaft will be pulled into the bottom of the shaft.<br />
<br />
For both the wet and dry casing methods, the casing is typically installed in a telescoping fashion, where the top casings may be larger than the drilled shaft diameter as called for on the plans. The depth of the hole will also dictate how many sections of casing are to be used. Ensure the contractor does not telescope the casings down to a diameter less than the design diameter as shown on the plans.<br />
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<br />
==[[#MATERIALS|MATERIALS]]==<br />
<br />
===[[#Concrete, Grade S2, and Grade T|Concrete, Grade S2, and Grade T]]===<br />
<br />
Ensure concrete materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf section 701] of the Standard Specifications for Construction, except modifications for the slump requirements per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction. Concrete Grade S2 is to be used for dry construction, and Concrete Grade T is to be used for wet construction.<br />
<br />
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<br />
===[[#Steel Reinforcement|Steel Reinforcement]]===<br />
<br />
Ensure steel reinforcement bars are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/905%20Steel%20Reinforcement.pdf section 905] of the Standard Specifications for Construction. Check the plans and specifications for epoxy rebar requirements.<br />
<br />
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<br />
===[[#Steel Casing|Steel Casing]]===<br />
<br />
Ensure steel casing materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/919%20Perm%20Traf%20Signs,%20Supports.pdf section 919.10] of the Standard Specifications for Construction. Permanent casing will also require Buy America certification, temporary casings will not, unless left in place.<br />
<br />
Review the plans for temporary casing-left in place cut off elevations. The Contractor is required to provide casing to be smooth and watertight, and capable of withstanding the pressure of concrete and the lateral earth pressures exerted down the length of the shaft. Ensure the outside diameter of the casing is at least equal to the diameter of the shaft as called for on the plans.<br />
<br />
Temporary casings should come equipped with hook holes, or other attachments to aid in the removal as the concrete pour advances. The concrete placement is to be complete prior to complete removal of the casing. The casings should be removed slowly, and with pull forces being in line with the shaft axis. Do not allow the contractor to pull shaft casings with equipment offset from the centerline of the shaft, as this will either disrupt the already placed concrete, or case caving of soil materials into the plastic concrete.<br />
<br />
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<br />
===[[#Polymer slurry|Polymer slurry]]===<br />
<br />
When wet construction methods are required, polymer type slurry is required. Bentonite slurry is prohibited. Ensure the polymer slurry is of sufficient specific gravity to ensure stability of the excavation during drilling operations, and allows for concrete placement. The Geotechnical Services area will typically review and approve the Contractor’s proposed polymer slurry materials.<br />
<br />
Ensure any polymer slurry used meets the requirements of [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Table 718-1] from the Standard Specifications for Construction. Ensure the Contractor maintains the height of polymer slurry to prevent the side walls of the excavation from caving, and the bottom from heaving.<br />
<br />
Ensure the contractor pre-mixes the polymer slurry materials with clean, fresh water, and allow time for hydration prior to pumping into shaft excavation. The polymer slurry should be agitated to prevent setting up in the shaft.<br />
<br />
If de-sanding is required, ensure the Contractor provides the appropriate equipment. Prior to placement of shaft concrete, take polymer slurry samples with a polymer slurry test kit to determine if heavily contaminated polymer slurry at the bottom of the shaft is to be removed. Ensure the Contractor controls and collects polymer slurry exiting the excavation as the concrete displaces the volume. Review the plans for polymer slurry handling and disposal requirements.<br />
<br />
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<br />
==[[#CONSTRUCTION|CONSTRUCTION]]==<br />
<br />
===[[#EQUIPMENT|Equipment]]===<br />
<br />
Ensure the contractor is using appropriate equipment to drill the shafts given the site conditions reported in the soil borings, and geotechnical subsurface exploration report. See Figure 1 for a typical drill rig set up. The major components of drill rig include:<br />
<br />
* Crawler or truck mounted auger<br />
* Auger of the appropriate type – rock auger, single or double flight earth auger. See Figure 2 for a double flight earth auger, see Figure 3 for a single flight rock auger.<br />
* Muck or clean out bucket – see Figures 4 and 5 for a muck bucket example.<br />
* Rock core barrel – see Figure 6 for a rock core barrel example.<br />
[[File:Fig 718-1.png|600px|framed|center|Figure 1. Typical drill rig set up]]<br />
<br />
[[File:Fig 718-2.png|600px|framed|center|Figure 2. Double flight earth auger]]<br />
<br />
[[File:Fig 718-3.png|600px|framed|center|Figure 3. Single flight rock auger]]<br />
<br />
[[File:Fig 718-4.png|600px|framed|center|Figure 4. Muck bucket]]<br />
<br />
[[File:Fig 718-5.png|600px|framed|center|Figure 5. Muck bucket bottom]]<br />
<br />
[[File:Fig 718-6.png|600px|framed|center|Figure 6. Soft rock core barrel]]<br />
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<br />
===[[#DRILLED SHAFT CONSTRUCTION|DRILLED SHAFT CONSTRUCTION]]===<br />
To track drilled shaft operations, use MDOT [http://mdotcf.state.mi.us/public/webforms/public/1988.pdf form 1988] – DRILLED SHAFT INSPECTION RECORD FOR HIGHWAY SIGNS, LUMINAIRES, AND TRAFFIC SIGNALS.<br />
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====[[#Prior to Drilled Shaft Operations|Prior to Drilled Shaft Operations]]====<br />
<br />
The Contractor is required to submit a Drilled Shaft Installation plan, per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.A] of the Standard Specifications for Construction. This plan is to detail all equipment to be used, the construction sequence, rebar and concrete placement, etc. The Geotechnical Services area will review and approve the Drilled Shaft Installation plan. Review and understand the following:<br />
<br />
* Proposed equipment, including cranes, drills, augers, core barrels, bailing buckets, cleaning equipment, polymer slurry pumps and cleaning equipment, tremie tubes or concrete pumps, and casing.<br />
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* Construction sequence, including methods to ensure a stable excavation, and removal of materials at the bottom of the shaft prior to rebar cage placement.<br />
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* Shaft excavation methods, including proposed excavation methods through supporting and caving soil layers.<br />
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* Method to mix, circulate and de-sand polymer slurry for wet construction methods.<br />
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* Reinforcement placement, including support and centering methods.<br />
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* Concrete placement, including free fall, tremie, or concrete pumping procedures.<br />
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* Methods to prevent drilled shaft excavation spoils from entering waterways, wetlands and floodplains.<br />
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* Fall protection plan conforming to MIOSHA Construction Safety Standards, including a rescue plan for shafts with a diameter of at least 30 inches, and at least 6 feet deep. This must be in place prior to commencement of any drilling operations.<br />
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* Conformance with shaft diameter and rebar requirements based on details shown in the plans.<br />
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Ensure the Contractor has brought all of the proposed equipment as stated in their approved Drilled Shaft Installation plan.<br />
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If the shaft is to be constructed during the wet method, verify if the Contractor is allowed to use water as the drilling fluid, or if polymer slurry is required. Typically, Contractors will want to use water, but water will not prevent caving in deeper shafts. The use of bentonite slurry is prohibited.<br />
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====[[#During Drilling Operations|During Drilling Operations]]====<br />
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Ensure the Contractor performs the following:<br />
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* Check the drilled shaft dimensions and the alignment with reference stakes and plumb bob.<br />
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* Check the dimensions and alignment of the casing inserted in the excavation.<br />
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* Insert a rigid rod assembly with several 90-degree offsets equal to the shaft diameter into the shaft excavation to ensure required diameter.<br />
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* Construction Method Log: The Contractor is required to submit a daily construction method log during drilled shaft excavation and construction per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.5] of the Standard Specifications for Construction. Ensure the following information is shown on the logs:<br />
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* Start dates and completions dates<br />
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* Drilled shaft identification number<br />
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* Location<br />
<br />
* Actual top and bottom elevation of drilled shaft <br />
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* Shaft diameter<br />
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* Final centerline location at top of shaft<br />
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* Variation of drilled shaft from plumb<br />
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* Top and bottom elevation of any permanent casing<br />
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* Description of each soil and rock material encountered during excavating and the top and bottom depths or elevations<br />
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* Depth drilled into bearing stratum<br />
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* Top and bottom elevations of obstructions encountered<br />
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* Amount of obstruction time<br />
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* Depth or elevation of encountered seepage of groundwater<br />
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* Actual volume of concrete placed, compared to the theoretical concrete volume to detect any large void or intrusions of extraneous materials<br />
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* Any remarks to better describe operations.<br />
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Ensure the Contractor maintains the required drilling fluid or polymer slurry levels to prevent caving.<br />
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Construction tolerances – Ensure the drilled shafts are within 3 inches horizontally of centerlines shown on the plans, and the drilled shaft is no more than 1 percent out of plumb, as measured horizontally from the actual center of the shaft at the shaft design top elevation.<br />
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Ensure the Contractor cleans each shaft so at least 50% of the base contains less than ½ inch of sediment. The shaft bottom should have no more than 1 ½ inches of debris above the required bottom elevation. Use a weighted tape to check the bottom of the shaft excavation for debris.<br />
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Marks on the Kelly Bar should be checked to ensure the required bottom of shaft elevation. Monitor the excavation to ensure the expected amount of materials are removed by the auger, if not, caving soils are present.<br />
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Ensure the top elevation of the drilled shaft is from +1 inch to -3 inches from the top of the shaft elevation shown on the plans. For shafts outside of this tolerance range, contact the Geotechnical Services area for recommendations as to corrections. [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Subsection 718.03.C.4] of the Standard Specifications for Construction dictates contractual obligations of the contractor to correct out of tolerance shafts.<br />
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Verify the soil cuttings as they are removed from the auger, and notify the Geotechnical Services area if soil cuttings appear different than those shown on the soil borings. Ensure the Contractor stores soil cuttings away from the drill shaft locations.<br />
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===[[#Obstruction Removal|Obstruction Removal]]===<br />
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Obstructions are to be removed per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.F.2] of the Standard Specifications for Construction. Obstructions may include old concrete foundations, abandoned utilities, or boulders and cobbles. Ensure the Contractor uses tools and procedures as approved by the Geotechnical Services Section to remove the obstructions. Special procedures and tools include:<br />
<br />
* Chisels<br />
* Boulder breakers<br />
* Core barrels<br />
* Air tools<br />
* Hand excavation<br />
* Temporary casing<br />
* Enlarging the drilled shaft diameter<br />
<br />
Removal of obstructions that require special equipment or tools will be measured and paid for as extra work per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.04.D] of the Standard Specifications or Construction. A budget amount will be established to pay for removing obstructions. If the Contractor and the Engineer cannot agree on a lump sum price, the Engineer will direct the work to be done on a force account basis.<br />
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===[[#Placing Steel Reinforcement|Placing Steel Reinforcement]]===<br />
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Check the plans and specifications to verify the Contractor is using the correct size longitudinal bars and lateral or spiral reinforcement, and correct bar lap lengths if used.<br />
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Reinforcing cage – maintain the top of the reinforcing steel cage no greater than 1 inch above, and no greater than 3 inches below the required position. Measure the distance between the top of shaft and the top of reinforcing cage with a straight edge, and direct the Contractor to correct the position if out of tolerance.<br />
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Ensure the Contractor provides a fully assembled steel reinforcement cage for inspection at least two working days before the start of construction. Ensure all longitudinal bars and lateral or spiral reinforcement is properly tied. Ensure plastic spacers are tied at the quarter points around the cage perimeter, but no greater than 30 inches apart.<br />
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Ensure the plastic spacers are spaced at intervals no greater than 5 feet along the length of the cage for #8 bar or smaller, and 10’ for bars larger than #8 to ensure a minimum annular space of 3 inches between the outside of the cage and the side of the excavation or casing. See Figure 7 for an example of plastic spacers on the rebar cage.<br />
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[[File:Fig 718-7.png|600px|framed|center|Figure 7. Rebar cage spacers]]<br />
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Ensure the Contractor does not use concrete blocks, wood blocks, or metal chairs as spacers, as these will not retain the required spacing, and will shift out of position during cage lowering, or during the concrete pour.<br />
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The Contractor may use concrete blocks at the bottom of the shaft to maintain concrete cover over the reinforcement. Ensure the Contractor picks and lowers the reinforcement cage into the shaft in a controlled manner, as not to cause racking or distorting of the tied cage. See Figure 8 for a typical reinforcement cage being lowered into the completed shaft.<br />
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[[File:Fig 718-8.png|600px|framed|center|Figure 8. Rebar cage being lowered into complete shaft]]<br />
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Ensure the Contractor holds down the cage to control vertical displacement during concrete placement or casing extraction.<br />
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===[[#Placing Concrete|Placing Concrete]]===<br />
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Ensure the Contractor places concrete as soon as possible after the excavation and reinforcement cage placement. If too much time has elapsed, loose or soft materials may accumulate at the bottom of the shaft, thus affecting the structural integrity. If this happens, direct the Contractor to remove the reinforcement cage, and remove loose or soft materials.<br />
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Use lighting to inspect the reinforcement cage and side of excavation for dry method construction. Ensure loose materials and groundwater is removed prior to placement of concrete.<br />
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Inspect by probing and measuring the shaft for wet method construction. The Contractor is required to place the concrete in one continuous operation starting from the bottom of the shaft. Once concrete reaches the top of the shaft, inspect the concrete for contaminants, and direct the Contractor to continue concrete placement until good quality concrete flows over the top of the shaft. The concrete should not be vibrated. Ensure the Contractor uses a sump or channel adjacent to the shaft to transmit displaced fluid and concrete away from the shaft opening. If polymer slurry is used, ensure the Contractor collects and disposes of the drilling fluids or polymer slurry appropriately. <br />
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Track the volume of concrete going into the shafts based on tickets, and perform theoretical concrete volume calculation based on the diameter and the length of the shaft. If the numbers vary by too much, it is possible a void is present.<br />
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====[[#Free Fall Concrete Placement|Free Fall Concrete Placement]]====<br />
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Free fall concrete placement can only be done in a dry shaft excavation.<br />
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The falling concrete cannot strike the sides of the excavation or the reinforcing cage. Ensure the Contractor uses a centering drop chute at least 3 feet long. If concrete strikes the sides of the excavation or the reinforcing cage, direct the Contractor to reduce the height of free fall, the rate of concrete flow, or both. The free fall height limit is 80 feet.<br />
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====[[#Tremie Tube Concrete Placement|Tremie Tube Concrete Placement]]====<br />
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Ensure the Contractor is using a tremie tube of at least 10 inches in diameter. Inspect the bottom of the Contractor’s tremie tube to ensure there is a bottom plate, valve, or plug so no water can get into the tube and contaminate the concrete prior to placement.<br />
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The tremie tube must be placed at the bottom of the shaft, and once the plate or plug is removed, or valve is opened, ensure the Contractor keeps the discharge end 5 feet to 10 feet immersed in concrete before raising the tremie tube.<br />
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It is ideal for the concrete to be placed continuously until complete, however, should the Contractor need to withdraw the tremie tube from the concrete, ensure the discharge end is re-sealed, charged with concrete, and inserted back into the concrete at least 10 feet before continuing with the concrete placement.<br />
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For cased shafts, it is important discharge keep a head of concrete above the bottom of casing to be removed, and then remove the casing slowly, to allow the concrete to fill the annular space created by the case thickness. If the concrete level goes down during case extraction, direct the Contractor to stop the extraction, and add more concrete.<br />
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The concrete must be placed in a timely fashion, so the slump does not go below 4”, as the concrete will not properly envelope the rebar cage, or fill the shaft to the required diameter. See Figure 9 for an example of concrete not filling the required shaft diameter.<br />
<br />
Allow the concrete to continue flowing at the top of the shaft, until quality concrete displaces all drilling fluid. Drilling fluid at the top of the shaft may have to be pumped of.<br />
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Ensure the Contractor provides a hand floated surface finish at the top of the shaft concrete per [http://mdotcf.state.mi.us/public/specbook/files/2012/706%20Str%20Conc%20Construction.pdf subsection 706.06.M.2] of the Standard Specifications for Construction.<br />
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* Do not remove the tremie tube from the concrete to take concrete QA samples.<br />
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[[File:Fig 718-9.png|600px|framed|center|Figure 9. Improper concrete placement]]<br />
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====[[#Pumped Concrete Placement|Pumped Concrete Placement]]====<br />
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Concrete can be pumped for by dry and wet shaft excavations, however, for use in wet excavations, ensure the Contractor provides a pump discharge tube with watertight joints.<br />
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Pumped concrete is very similar to tremie concrete in terms of operations. The main issue to watch is the sway and movement of the pumping pipes during concrete placement. Ensure the Contractor guides or anchors the pumping pipes as to not disturb already placed fresh concrete.<br />
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===[[#POST CONSTRUCTION INTEGRITY TESTING|POST CONSTRUCTION INTEGRITY TESTING]]===<br />
<br />
Check the plans and specifications for any type of post construction integrity testing to be done on the completed shaft. There are several methods of non-destructive testing:<br />
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====[[#Pulse Echo Integrity Testing|Pulse Echo Integrity Testing]]====<br />
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This type of test involves setting an ultrasonic transducer on the surfaces of the concrete, which send wave pulses through the material. Wave pulses will continue through solid concrete until a concrete to air interface, at which time the pulse is reflected back to the transducer, and a depth can be measured. In the presence of voids, the wave would reflect back sooner than expected given the overall thickness of the materials.<br />
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====[[#Cross Hole Sonic Logging|Cross Hole Sonic Logging]]====<br />
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This type of test involves the attachment of steel access tubes to the vertical cage rebar prior to concrete placement. The concrete is then placed and allowed to cure. Immediately after concrete placement, the steel access tubes are to be filled with water to protect from concrete infiltration. After curing, a sound source and a received are lowered into the steel access tubes, and while keeping them at the same elevation, sonic pulses are emitted from the sound source, and the wave generated is picked up by the receiver. Based on the speed the wave propagates through the material, the receiver maps the integrity of the surrounding concrete, and voids are reported where the wave returns to the receiver at faster rates than sound areas.<br />
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These types of tests are typically performed by a skilled technician, or MDOT prequalified consultant. The [http://www.michigan.gov/mdot/0,4616,7-151-9623_26663_27303-269622--,00.html Geotechnical Services Section] will be present during integrity testing to help analyze and interpret results.<br />
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====[[#Coring|Coring]]====<br />
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Coring is a destructive test to remove cores of concrete from the finished shaft, and perform testing to determine concrete quality. Coring may also be done when voids are identified during non-destructive tests to reach the detected void. Grout can then be used to fill the void, and the core holes.<br />
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==[[#MEASUREMENT AND PAYMENT|MEASUREMENT AND PAYMENT]]==<br />
<br />
<span style="color: red"> -Reserved- </span><br />
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[[Category:Construction Manual]]<br />
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<center><span STYLE="font: 60pt arial;">'''719'''</span></center><br />
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<center><span STYLE="font: 40pt arial;">'''Earth Retaining Structures'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/719%20Earth%20Retaining%Structures.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 719]</center><br />
<br />
==[[#General|General]]==<br />
<br />
Below is a list with definitions of common earth retaining structures utilized by MDOT:<br />
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*Abutment – A structure located at the end of a bridge span that supports the vertical loads from the bridge superstructure, and resists lateral loads from fill material on which the roadway rests immediately adjacent to the bridge.<br />
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*Anchored Wall – An earth retaining system typically composed of the same elements as non-gravity cantilevered walls and that derive additional lateral resistance from one or more tiers of anchors.<br />
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*Mechanically Stabilized Earth (MSE) Wall – A soil-retaining system, employing either strip or grid-type, metallic, or polymeric tensile reinforcements in the soil mass, and a facing element that is either vertical or nearly vertical.<br />
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*Segmental Block Retaining Wall – A soil-retaining system, typically employing polymeric tensile reinforcements in the soil mass attached to a facing element that consists of segmental blocks. Segmental blocks are typically dry cast blocks.<br />
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*Modular Block Retaining Wall – A soil-retaining system that consists of modular blocks stacked to form a gravity wall with a vertical or nearly vertical face. Modular blocks are typically large precast concrete blocks.<br />
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*Non-Gravity Cantilever Retaining Wall – A soil-retaining system that derives lateral resistance through embedment of vertical wall elements and supports retained soil with facing elements. Vertical wall elements may consist of discrete elements (piles, drilled shafts, etc.) or a continuous system (sheet piles, tangent drilled shafts, etc.).<br />
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*Rigid Gravity and Semi-Gravity Retaining Wall – A structure that provides lateral support for a mass of soil and that owes its stability primarily to its own weight and to the weight of any soil located directly above its base.<br />
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Some of these elements may not be detailed on the plans, and may require shop drawing submittals for approval. See 707 of the MDOT Construction Manual for shop drawing requirements.<br />
<br />
==[[#Abutments|Abutments]]==<br />
<br />
MDOT utilizes the following types of abutments:<br />
<br />
*Curtainwall Abutment (see rigid-gravity retaining wall below);<br />
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[[File:Fig 719.png|600px|framed|center|Figure 1. Unreinforced concrete rigid-gravity wall, or curtain wall abutment]]<br />
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*Cantilevered Abutment (see semi-gravity retaining wall below)<br />
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[[File:Fig 719.png|600px|framed|center|Figure 2. reinforced cantilever abutment wall]]<br />
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*Integral and Semi-Integral Abutments – Integral and semi-integral abutments are detailed in the MDOT Bridge Design Guides 6.20.04, 6.20.04B, 6.20.04D.<br />
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Integral abutments are designed to be supported on a single row of piles that are oriented with their webs parallel to the bridge reference line to allow weak axis bending to accommodate superstructure articulation due to thermal gradient and live loading. Splices for piles in integral abutments must be complete joint penetration (CJP). Alternative mechanical splicer channels are not permitted.<br />
<br />
==[[#Anchored Wall|Anchored Wall]]==<br />
<br />
Anchored walls can consist of ground anchors or tie backs. Verification load testing and proof load testing of the ground anchors is typically performed on all anchors to ensure the actual lateral pullout resistance is within the design tolerances. The verification load testing procedures will be detailed in the contract documents.<br />
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<br />
<br />
==[[#Mechanically Stabilized Earth Wall| Mechanically Stabilized Earth Wall]]==<br />
<br />
Below are the basic components of a mechanically stabilized earth (MSE) wall system and a summary of items to review during construction:<br />
<br />
:A.Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed. Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.<br />
<br />
:B.Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office. <br />
Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.<br />
<br />
:C. Wire Facing Panels – Wire facing panels are typically specified for temporary MSE walls during Stage I construction. The walls end up being buried into the final structure and are not removed. The wire facing panels in this temporary application are usually black steel due to the short duration of use.<br />
<br />
:D. Soil Reinforcement – MDOT permits the use of steel strip-type (bar or welded wire fabric ladder) reinforcement. Soil reinforcement must be placed as close to perpendicular from the wall face as practical. The reinforcement is permitted to be skewed around piling or other obstructions, but should be done so to not only reduce the skew, but also the number of skewed reinforcement strips. Reinforcement should not be in contact with other reinforcement. For skewed reinforcement soil must be placed between overlapping reinforcement. <br />
<br />
:E. Bolts – Bolts are typically positioned with the head at the bottom side of the connection lug and the washer and nut on the top side. This allows the inspector to visually inspect that the washers and nuts have been installed as the reinforced soil is constructed behind the wall. <br />
<br />
:F. Concrete Facing Panel Joint Material – Geotextile fabric is used to prevent soil particles from moving through the concrete facing panels. If the facing panel joints start to open up then the contractor should double the geotextile over the joints in question to provide additional protection.<br />
<br />
:G. Backfill for Reinforced Soil Mass – Granular soil, typically Granular Material Class II, whic is free draining and meets the required strength and electro-chemical properties. This material must be tested and approved prior to placement.<br />
<br />
:H. Leveling Pad – Is a non-reinforced concrete pad that provides a level starting point for constructing the precast concrete facing panels. A leveling pad is not needed for a wire faced MSE wall.<br />
<br />
:I. Impervious Membrane – A polyvinylchloride (PVC) liner that prevents chloride laden runoff from penetrating into the reinforced soil mass and corroding the steel reinforcement. The liner must be shingle-lapped or seam welded and is positioned to slope away from the front of the wall and extend a minimum distance beyond the end of the soil reinforcement.<br />
<br />
:J. CIP Copings – These copings are typically used as closure pours, but can also run up to 20 feet in length and can overlap adjacent panels without the need for a bond breaker. Expansion joint material is needed when butting CIP coping up to precast coping.<br />
<br />
:K. Foundation Underdrains – Are strategically placed to transport water from the reinforced soil mass to a location far away from the wall. MSE walls are generally not designed for hydrostatic pressure. Foundation underdrains are to be installed at the locations indicated on the plans. The lower foundation underdrains are to be located as low as possible but still drain to either a ditch or a drainage structure.<br />
<br />
MSE Wall Construction Considerations<br />
<br />
*During the wet cure for the concrete bridge deck the water coming off of the deck needs to be collected and discharged away from the MSE wall. Water runoff from the deck may saturate the MSE backfill and cause wall movement.<br />
<br />
*Groundwater needs to be controlled to prevent hydrostatic forces from acting on the wall. If groundwater is encountered during construction the location/number of foundation underdrains may need to be reevaluated.<br />
<br />
*Compaction of the Select Backfill and any subgrade undercuts is important in order to limit any future settlement of the MSE wall fill.<br />
<br />
[[File:Fig 719-3.png|600px|framed|center|Figure 1. MSE wall]]<br />
<br />
==[[#Non-Gravity Cantilevered Retaining Wall| Non-Gravity Cantilevered Retaining Wall]]==<br />
<br />
Examples of on-gravity cantilevered retaining walls are listed below:<br />
*Tangent piles or drilled shafts;<br />
*Drilled shafts or auger-cast piles spanned by structural facing (lagging, panels or shotcrete);<br />
*Steel sheet piling (see Section 704 – Steel Sheet Piling and Cofferdams).<br />
<br />
==[[#Rigid-Gravity and Semi-Gravity Retaining Wall|Rigid-Gravity and Semi-Gravity Retaining Wall]]==<br />
<br />
[[File:Fig719-4.png|600px|framed|center|Figure 3. Reinforced concrete counterfort semi-gravity wall]]<br />
<br />
<br />
<br />
[[File:Fig719-5.png|600px|framed|center|Figure 4. Reinforced concrete cantilever semi-gravity wall.]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=718_-_Drilled_Shafts&diff=3879718 - Drilled Shafts2014-11-12T19:22:14Z<p>HarrisR18: /* Rigid-Gravity and Semi-Gravity Retaining Wall */</p>
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<div><br />
<center><span STYLE="font: 60pt arial;">'''718'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Drilled Shafts'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 718]</center><br />
<br />
<br />
==[[#GENERAL|GENERAL]]==<br />
<br />
Drilled shaft foundations are also referred to caissons, drilled piers, or bored piles, and consist of circular shafts of varying diameter, drilled to a design depth, reinforced with a steel rebar cage, and filled with concrete. Drilled shaft foundations can support large loads, and are used when driving steel piles is not feasible, or surrounding structures or utilities are too sensitive to survive the vibrations from steel foundation pile driving operations. Like steel foundation piles, loads from the superstructure transfer into the drilled shafts, which transfer loads to soil layers through side friction, end bearing, or a combination of the two. Drilled shafts are used for bridge foundations, and other ancillary structure foundations such as sign cantilevers and trusses, and signal strain poles.<br />
<br />
Drilled shafts can be constructed in the dry, or in the wet, and can also include a steel casing.<br />
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===[[#DRY CONSTRUCTION METHOD|DRY CONSTRUCTION METHOD]]===<br />
<br />
Dry construction methods are generally used when the water table is below the bottom of the shaft, and the existing soils are stiff enough as not to sloughing or caving into the hole during drilling operations. Any accumulated water greater than 3 inches at the bottom of the shaft must be pumped out prior to rebar and concrete placement, and during concrete placement, water cannot flow into the shaft at a rate greater than 12 inches within 1 hour.<br />
<br />
Typical issues with dry construction methods are if the soils are unstable, or the water table is too high, but the Contractor attempts to force dry shaft construction. In this scenario, soil caving problems will lead to soil inclusions in the shaft concrete, affecting the shaft integrity. If any problems like this arise during construction, contact the Geotechnical Services area.<br />
<br />
Another issue to watch for is if the Contractor leaves the excavation open for too long prior to reinforcement cage and concrete placement. Soils that were capable of maintaining hole stability during the drilling operations may shrink or swell over time and slowly lose that ability, resulting in caving leading to soil inclusions in the shaft concrete affecting the shaft integrity.<br />
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===[[#WET CONSTRUCTION METHOD|WET CONSTRUCTION METHOD]]===<br />
<br />
Wets construction methods are generally used where a dry excavation cannot be maintained during drilling, or shaft concrete placement. This typically occurs in areas of high water tables, and sandy soils that would otherwise slough or cave into the shaft during drilling operations. Water or a polymer slurry is used to contain water seepage, and maintain stability of the shaft excavation. Polymer slurry must be de-sanded and cleaned if used. Temporary surface casings are typically used to ensure shaft alignment. The rebar cage is lowered into the shaft, and concrete is placed using a tremie tube, or concrete pump capable of reaching the bottom of the shaft.<br />
<br />
Typical issues with wet construction methods are inexperienced Contractors that do not understand the mechanics of polymer slurry construction, and the need to ensure proper suspension of sediment and cuttings for removal, and control of caving. This can lead to shafts not being properly cleaned of sediment, resulting in voids, or inclusions in the concrete, affecting the shaft integrity.<br />
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===[[#DRY TEMPORARY CASING METHOD|DRY TEMPORARY CASING METHOD]]===<br />
<br />
Dry temporary cased construction methods are generally used where caving soils occur, over soil or rock deformations are expected, but the casing can maintain a dry and stable excavation. The casing is advanced simultaneously with the excavation. After placement of the rebar cage, the casing is then withdrawn slowly during concrete placement until removed at the top of shaft.<br />
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===[[#WET TEMPORARY CASING METHOD|WET TEMPORARY CASING METHOD]]===<br />
<br />
Wet temporary cased construction methods are generally used where caving soils occur, and a dry excavation cannot be maintained, the soils are too permeable, and the groundwater is higher than the bottom of the shaft. The casing is advanced simultaneously with the excavation, but it is important that no drilling occur outside the casing through any caving soil layers. After placement of the rebar cage, the concrete is placed using a tremie tube or concrete pump capable of reaching the bottom of the shaft. The water in the casing is not to be pumped out, rather it is to be displaced by the concrete placement.<br />
<br />
It is important to ensure the Contractor maintains a positive fluid pressure head in the shaft above the ground water elevation, or material from the side walls of the shaft will be pulled into the bottom of the shaft.<br />
<br />
For both the wet and dry casing methods, the casing is typically installed in a telescoping fashion, where the top casings may be larger than the drilled shaft diameter as called for on the plans. The depth of the hole will also dictate how many sections of casing are to be used. Ensure the contractor does not telescope the casings down to a diameter less than the design diameter as shown on the plans.<br />
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<br />
==[[#MATERIALS|MATERIALS]]==<br />
<br />
===[[#Concrete, Grade S2, and Grade T|Concrete, Grade S2, and Grade T]]===<br />
<br />
Ensure concrete materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf section 701] of the Standard Specifications for Construction, except modifications for the slump requirements per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction. Concrete Grade S2 is to be used for dry construction, and Concrete Grade T is to be used for wet construction.<br />
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===[[#Steel Reinforcement|Steel Reinforcement]]===<br />
<br />
Ensure steel reinforcement bars are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/905%20Steel%20Reinforcement.pdf section 905] of the Standard Specifications for Construction. Check the plans and specifications for epoxy rebar requirements.<br />
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===[[#Steel Casing|Steel Casing]]===<br />
<br />
Ensure steel casing materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/919%20Perm%20Traf%20Signs,%20Supports.pdf section 919.10] of the Standard Specifications for Construction. Permanent casing will also require Buy America certification, temporary casings will not, unless left in place.<br />
<br />
Review the plans for temporary casing-left in place cut off elevations. The Contractor is required to provide casing to be smooth and watertight, and capable of withstanding the pressure of concrete and the lateral earth pressures exerted down the length of the shaft. Ensure the outside diameter of the casing is at least equal to the diameter of the shaft as called for on the plans.<br />
<br />
Temporary casings should come equipped with hook holes, or other attachments to aid in the removal as the concrete pour advances. The concrete placement is to be complete prior to complete removal of the casing. The casings should be removed slowly, and with pull forces being in line with the shaft axis. Do not allow the contractor to pull shaft casings with equipment offset from the centerline of the shaft, as this will either disrupt the already placed concrete, or case caving of soil materials into the plastic concrete.<br />
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<br />
===[[#Polymer slurry|Polymer slurry]]===<br />
<br />
When wet construction methods are required, polymer type slurry is required. Bentonite slurry is prohibited. Ensure the polymer slurry is of sufficient specific gravity to ensure stability of the excavation during drilling operations, and allows for concrete placement. The Geotechnical Services area will typically review and approve the Contractor’s proposed polymer slurry materials.<br />
<br />
Ensure any polymer slurry used meets the requirements of [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Table 718-1] from the Standard Specifications for Construction. Ensure the Contractor maintains the height of polymer slurry to prevent the side walls of the excavation from caving, and the bottom from heaving.<br />
<br />
Ensure the contractor pre-mixes the polymer slurry materials with clean, fresh water, and allow time for hydration prior to pumping into shaft excavation. The polymer slurry should be agitated to prevent setting up in the shaft.<br />
<br />
If de-sanding is required, ensure the Contractor provides the appropriate equipment. Prior to placement of shaft concrete, take polymer slurry samples with a polymer slurry test kit to determine if heavily contaminated polymer slurry at the bottom of the shaft is to be removed. Ensure the Contractor controls and collects polymer slurry exiting the excavation as the concrete displaces the volume. Review the plans for polymer slurry handling and disposal requirements.<br />
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<br />
==[[#CONSTRUCTION|CONSTRUCTION]]==<br />
<br />
===[[#EQUIPMENT|Equipment]]===<br />
<br />
Ensure the contractor is using appropriate equipment to drill the shafts given the site conditions reported in the soil borings, and geotechnical subsurface exploration report. See Figure 1 for a typical drill rig set up. The major components of drill rig include:<br />
<br />
* Crawler or truck mounted auger<br />
* Auger of the appropriate type – rock auger, single or double flight earth auger. See Figure 2 for a double flight earth auger, see Figure 3 for a single flight rock auger.<br />
* Muck or clean out bucket – see Figures 4 and 5 for a muck bucket example.<br />
* Rock core barrel – see Figure 6 for a rock core barrel example.<br />
[[File:Fig 718-1.png|600px|framed|center|Figure 1. Typical drill rig set up]]<br />
<br />
[[File:Fig 718-2.png|600px|framed|center|Figure 2. Double flight earth auger]]<br />
<br />
[[File:Fig 718-3.png|600px|framed|center|Figure 3. Single flight rock auger]]<br />
<br />
[[File:Fig 718-4.png|600px|framed|center|Figure 4. Muck bucket]]<br />
<br />
[[File:Fig 718-5.png|600px|framed|center|Figure 5. Muck bucket bottom]]<br />
<br />
[[File:Fig 718-6.png|600px|framed|center|Figure 6. Soft rock core barrel]]<br />
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===[[#DRILLED SHAFT CONSTRUCTION|DRILLED SHAFT CONSTRUCTION]]===<br />
To track drilled shaft operations, use MDOT [http://mdotcf.state.mi.us/public/webforms/public/1988.pdf form 1988] – DRILLED SHAFT INSPECTION RECORD FOR HIGHWAY SIGNS, LUMINAIRES, AND TRAFFIC SIGNALS.<br />
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====[[#Prior to Drilled Shaft Operations|Prior to Drilled Shaft Operations]]====<br />
<br />
The Contractor is required to submit a Drilled Shaft Installation plan, per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.A] of the Standard Specifications for Construction. This plan is to detail all equipment to be used, the construction sequence, rebar and concrete placement, etc. The Geotechnical Services area will review and approve the Drilled Shaft Installation plan. Review and understand the following:<br />
<br />
* Proposed equipment, including cranes, drills, augers, core barrels, bailing buckets, cleaning equipment, polymer slurry pumps and cleaning equipment, tremie tubes or concrete pumps, and casing.<br />
<br />
* Construction sequence, including methods to ensure a stable excavation, and removal of materials at the bottom of the shaft prior to rebar cage placement.<br />
<br />
* Shaft excavation methods, including proposed excavation methods through supporting and caving soil layers.<br />
<br />
* Method to mix, circulate and de-sand polymer slurry for wet construction methods.<br />
<br />
* Reinforcement placement, including support and centering methods.<br />
<br />
* Concrete placement, including free fall, tremie, or concrete pumping procedures.<br />
<br />
* Methods to prevent drilled shaft excavation spoils from entering waterways, wetlands and floodplains.<br />
<br />
* Fall protection plan conforming to MIOSHA Construction Safety Standards, including a rescue plan for shafts with a diameter of at least 30 inches, and at least 6 feet deep. This must be in place prior to commencement of any drilling operations.<br />
<br />
* Conformance with shaft diameter and rebar requirements based on details shown in the plans.<br />
<br />
Ensure the Contractor has brought all of the proposed equipment as stated in their approved Drilled Shaft Installation plan.<br />
<br />
If the shaft is to be constructed during the wet method, verify if the Contractor is allowed to use water as the drilling fluid, or if polymer slurry is required. Typically, Contractors will want to use water, but water will not prevent caving in deeper shafts. The use of bentonite slurry is prohibited.<br />
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====[[#During Drilling Operations|During Drilling Operations]]====<br />
<br />
Ensure the Contractor performs the following:<br />
<br />
* Check the drilled shaft dimensions and the alignment with reference stakes and plumb bob.<br />
<br />
* Check the dimensions and alignment of the casing inserted in the excavation.<br />
<br />
* Insert a rigid rod assembly with several 90-degree offsets equal to the shaft diameter into the shaft excavation to ensure required diameter.<br />
<br />
* Construction Method Log: The Contractor is required to submit a daily construction method log during drilled shaft excavation and construction per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.5] of the Standard Specifications for Construction. Ensure the following information is shown on the logs:<br />
<br />
* Start dates and completions dates<br />
<br />
* Drilled shaft identification number<br />
<br />
* Location<br />
<br />
* Actual top and bottom elevation of drilled shaft <br />
<br />
* Shaft diameter<br />
<br />
* Final centerline location at top of shaft<br />
<br />
* Variation of drilled shaft from plumb<br />
<br />
* Top and bottom elevation of any permanent casing<br />
<br />
* Description of each soil and rock material encountered during excavating and the top and bottom depths or elevations<br />
<br />
* Depth drilled into bearing stratum<br />
<br />
* Top and bottom elevations of obstructions encountered<br />
<br />
* Amount of obstruction time<br />
<br />
* Depth or elevation of encountered seepage of groundwater<br />
<br />
* Actual volume of concrete placed, compared to the theoretical concrete volume to detect any large void or intrusions of extraneous materials<br />
<br />
* Any remarks to better describe operations.<br />
<br />
Ensure the Contractor maintains the required drilling fluid or polymer slurry levels to prevent caving.<br />
<br />
Construction tolerances – Ensure the drilled shafts are within 3 inches horizontally of centerlines shown on the plans, and the drilled shaft is no more than 1 percent out of plumb, as measured horizontally from the actual center of the shaft at the shaft design top elevation.<br />
<br />
Ensure the Contractor cleans each shaft so at least 50% of the base contains less than ½ inch of sediment. The shaft bottom should have no more than 1 ½ inches of debris above the required bottom elevation. Use a weighted tape to check the bottom of the shaft excavation for debris.<br />
<br />
Marks on the Kelly Bar should be checked to ensure the required bottom of shaft elevation. Monitor the excavation to ensure the expected amount of materials are removed by the auger, if not, caving soils are present.<br />
<br />
Ensure the top elevation of the drilled shaft is from +1 inch to -3 inches from the top of the shaft elevation shown on the plans. For shafts outside of this tolerance range, contact the Geotechnical Services area for recommendations as to corrections. [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Subsection 718.03.C.4] of the Standard Specifications for Construction dictates contractual obligations of the contractor to correct out of tolerance shafts.<br />
<br />
Verify the soil cuttings as they are removed from the auger, and notify the Geotechnical Services area if soil cuttings appear different than those shown on the soil borings. Ensure the Contractor stores soil cuttings away from the drill shaft locations.<br />
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===[[#Obstruction Removal|Obstruction Removal]]===<br />
<br />
Obstructions are to be removed per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.F.2] of the Standard Specifications for Construction. Obstructions may include old concrete foundations, abandoned utilities, or boulders and cobbles. Ensure the Contractor uses tools and procedures as approved by the Geotechnical Services Section to remove the obstructions. Special procedures and tools include:<br />
<br />
* Chisels<br />
* Boulder breakers<br />
* Core barrels<br />
* Air tools<br />
* Hand excavation<br />
* Temporary casing<br />
* Enlarging the drilled shaft diameter<br />
<br />
Removal of obstructions that require special equipment or tools will be measured and paid for as extra work per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.04.D] of the Standard Specifications or Construction. A budget amount will be established to pay for removing obstructions. If the Contractor and the Engineer cannot agree on a lump sum price, the Engineer will direct the work to be done on a force account basis.<br />
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===[[#Placing Steel Reinforcement|Placing Steel Reinforcement]]===<br />
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Check the plans and specifications to verify the Contractor is using the correct size longitudinal bars and lateral or spiral reinforcement, and correct bar lap lengths if used.<br />
<br />
Reinforcing cage – maintain the top of the reinforcing steel cage no greater than 1 inch above, and no greater than 3 inches below the required position. Measure the distance between the top of shaft and the top of reinforcing cage with a straight edge, and direct the Contractor to correct the position if out of tolerance.<br />
<br />
Ensure the Contractor provides a fully assembled steel reinforcement cage for inspection at least two working days before the start of construction. Ensure all longitudinal bars and lateral or spiral reinforcement is properly tied. Ensure plastic spacers are tied at the quarter points around the cage perimeter, but no greater than 30 inches apart.<br />
<br />
Ensure the plastic spacers are spaced at intervals no greater than 5 feet along the length of the cage for #8 bar or smaller, and 10’ for bars larger than #8 to ensure a minimum annular space of 3 inches between the outside of the cage and the side of the excavation or casing. See Figure 7 for an example of plastic spacers on the rebar cage.<br />
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[[File:Fig 718-7.png|600px|framed|center|Figure 7. Rebar cage spacers]]<br />
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Ensure the Contractor does not use concrete blocks, wood blocks, or metal chairs as spacers, as these will not retain the required spacing, and will shift out of position during cage lowering, or during the concrete pour.<br />
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The Contractor may use concrete blocks at the bottom of the shaft to maintain concrete cover over the reinforcement. Ensure the Contractor picks and lowers the reinforcement cage into the shaft in a controlled manner, as not to cause racking or distorting of the tied cage. See Figure 8 for a typical reinforcement cage being lowered into the completed shaft.<br />
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[[File:Fig 718-8.png|600px|framed|center|Figure 8. Rebar cage being lowered into complete shaft]]<br />
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Ensure the Contractor holds down the cage to control vertical displacement during concrete placement or casing extraction.<br />
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===[[#Placing Concrete|Placing Concrete]]===<br />
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Ensure the Contractor places concrete as soon as possible after the excavation and reinforcement cage placement. If too much time has elapsed, loose or soft materials may accumulate at the bottom of the shaft, thus affecting the structural integrity. If this happens, direct the Contractor to remove the reinforcement cage, and remove loose or soft materials.<br />
<br />
Use lighting to inspect the reinforcement cage and side of excavation for dry method construction. Ensure loose materials and groundwater is removed prior to placement of concrete.<br />
<br />
Inspect by probing and measuring the shaft for wet method construction. The Contractor is required to place the concrete in one continuous operation starting from the bottom of the shaft. Once concrete reaches the top of the shaft, inspect the concrete for contaminants, and direct the Contractor to continue concrete placement until good quality concrete flows over the top of the shaft. The concrete should not be vibrated. Ensure the Contractor uses a sump or channel adjacent to the shaft to transmit displaced fluid and concrete away from the shaft opening. If polymer slurry is used, ensure the Contractor collects and disposes of the drilling fluids or polymer slurry appropriately. <br />
<br />
Track the volume of concrete going into the shafts based on tickets, and perform theoretical concrete volume calculation based on the diameter and the length of the shaft. If the numbers vary by too much, it is possible a void is present.<br />
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====[[#Free Fall Concrete Placement|Free Fall Concrete Placement]]====<br />
<br />
Free fall concrete placement can only be done in a dry shaft excavation.<br />
<br />
The falling concrete cannot strike the sides of the excavation or the reinforcing cage. Ensure the Contractor uses a centering drop chute at least 3 feet long. If concrete strikes the sides of the excavation or the reinforcing cage, direct the Contractor to reduce the height of free fall, the rate of concrete flow, or both. The free fall height limit is 80 feet.<br />
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====[[#Tremie Tube Concrete Placement|Tremie Tube Concrete Placement]]====<br />
<br />
Ensure the Contractor is using a tremie tube of at least 10 inches in diameter. Inspect the bottom of the Contractor’s tremie tube to ensure there is a bottom plate, valve, or plug so no water can get into the tube and contaminate the concrete prior to placement.<br />
<br />
The tremie tube must be placed at the bottom of the shaft, and once the plate or plug is removed, or valve is opened, ensure the Contractor keeps the discharge end 5 feet to 10 feet immersed in concrete before raising the tremie tube.<br />
<br />
It is ideal for the concrete to be placed continuously until complete, however, should the Contractor need to withdraw the tremie tube from the concrete, ensure the discharge end is re-sealed, charged with concrete, and inserted back into the concrete at least 10 feet before continuing with the concrete placement.<br />
<br />
For cased shafts, it is important discharge keep a head of concrete above the bottom of casing to be removed, and then remove the casing slowly, to allow the concrete to fill the annular space created by the case thickness. If the concrete level goes down during case extraction, direct the Contractor to stop the extraction, and add more concrete.<br />
<br />
The concrete must be placed in a timely fashion, so the slump does not go below 4”, as the concrete will not properly envelope the rebar cage, or fill the shaft to the required diameter. See Figure 9 for an example of concrete not filling the required shaft diameter.<br />
<br />
Allow the concrete to continue flowing at the top of the shaft, until quality concrete displaces all drilling fluid. Drilling fluid at the top of the shaft may have to be pumped of.<br />
<br />
Ensure the Contractor provides a hand floated surface finish at the top of the shaft concrete per [http://mdotcf.state.mi.us/public/specbook/files/2012/706%20Str%20Conc%20Construction.pdf subsection 706.06.M.2] of the Standard Specifications for Construction.<br />
<br />
* Do not remove the tremie tube from the concrete to take concrete QA samples.<br />
<br />
[[File:Fig 718-9.png|600px|framed|center|Figure 9. Improper concrete placement]]<br />
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====[[#Pumped Concrete Placement|Pumped Concrete Placement]]====<br />
<br />
Concrete can be pumped for by dry and wet shaft excavations, however, for use in wet excavations, ensure the Contractor provides a pump discharge tube with watertight joints.<br />
<br />
Pumped concrete is very similar to tremie concrete in terms of operations. The main issue to watch is the sway and movement of the pumping pipes during concrete placement. Ensure the Contractor guides or anchors the pumping pipes as to not disturb already placed fresh concrete.<br />
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===[[#POST CONSTRUCTION INTEGRITY TESTING|POST CONSTRUCTION INTEGRITY TESTING]]===<br />
<br />
Check the plans and specifications for any type of post construction integrity testing to be done on the completed shaft. There are several methods of non-destructive testing:<br />
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====[[#Pulse Echo Integrity Testing|Pulse Echo Integrity Testing]]====<br />
<br />
This type of test involves setting an ultrasonic transducer on the surfaces of the concrete, which send wave pulses through the material. Wave pulses will continue through solid concrete until a concrete to air interface, at which time the pulse is reflected back to the transducer, and a depth can be measured. In the presence of voids, the wave would reflect back sooner than expected given the overall thickness of the materials.<br />
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====[[#Cross Hole Sonic Logging|Cross Hole Sonic Logging]]====<br />
<br />
This type of test involves the attachment of steel access tubes to the vertical cage rebar prior to concrete placement. The concrete is then placed and allowed to cure. Immediately after concrete placement, the steel access tubes are to be filled with water to protect from concrete infiltration. After curing, a sound source and a received are lowered into the steel access tubes, and while keeping them at the same elevation, sonic pulses are emitted from the sound source, and the wave generated is picked up by the receiver. Based on the speed the wave propagates through the material, the receiver maps the integrity of the surrounding concrete, and voids are reported where the wave returns to the receiver at faster rates than sound areas.<br />
<br />
These types of tests are typically performed by a skilled technician, or MDOT prequalified consultant. The [http://www.michigan.gov/mdot/0,4616,7-151-9623_26663_27303-269622--,00.html Geotechnical Services Section] will be present during integrity testing to help analyze and interpret results.<br />
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====[[#Coring|Coring]]====<br />
<br />
Coring is a destructive test to remove cores of concrete from the finished shaft, and perform testing to determine concrete quality. Coring may also be done when voids are identified during non-destructive tests to reach the detected void. Grout can then be used to fill the void, and the core holes.<br />
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==[[#MEASUREMENT AND PAYMENT|MEASUREMENT AND PAYMENT]]==<br />
<br />
<span style="color: red"> -Reserved- </span><br />
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[[Category:Construction Manual]]<br />
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<br />
<center><span STYLE="font: 60pt arial;">'''719'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Earth Retaining Structures'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/719%20Earth%20Retaining%Structures.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 719]</center><br />
<br />
==[[#General|General]]==<br />
<br />
Below is a list with definitions of common earth retaining structures utilized by MDOT:<br />
<br />
*Abutment – A structure located at the end of a bridge span that supports the vertical loads from the bridge superstructure, and resists lateral loads from fill material on which the roadway rests immediately adjacent to the bridge.<br />
<br />
*Anchored Wall – An earth retaining system typically composed of the same elements as non-gravity cantilevered walls and that derive additional lateral resistance from one or more tiers of anchors.<br />
<br />
*Mechanically Stabilized Earth (MSE) Wall – A soil-retaining system, employing either strip or grid-type, metallic, or polymeric tensile reinforcements in the soil mass, and a facing element that is either vertical or nearly vertical.<br />
<br />
*Segmental Block Retaining Wall – A soil-retaining system, typically employing polymeric tensile reinforcements in the soil mass attached to a facing element that consists of segmental blocks. Segmental blocks are typically dry cast blocks.<br />
<br />
*Modular Block Retaining Wall – A soil-retaining system that consists of modular blocks stacked to form a gravity wall with a vertical or nearly vertical face. Modular blocks are typically large precast concrete blocks.<br />
<br />
*Non-Gravity Cantilever Retaining Wall – A soil-retaining system that derives lateral resistance through embedment of vertical wall elements and supports retained soil with facing elements. Vertical wall elements may consist of discrete elements (piles, drilled shafts, etc.) or a continuous system (sheet piles, tangent drilled shafts, etc.).<br />
<br />
*Rigid Gravity and Semi-Gravity Retaining Wall – A structure that provides lateral support for a mass of soil and that owes its stability primarily to its own weight and to the weight of any soil located directly above its base.<br />
<br />
Some of these elements may not be detailed on the plans, and may require shop drawing submittals for approval. See 707 of the MDOT Construction Manual for shop drawing requirements.<br />
<br />
==[[#Abutments|Abutments]]==<br />
<br />
MDOT utilizes the following types of abutments:<br />
<br />
*Curtainwall Abutment (see rigid-gravity retaining wall below);<br />
<br />
<br />
[[File:Fig 719.png|600px|framed|center|Figure 1. Unreinforced concrete rigid-gravity wall, or curtain wall abutment]]<br />
<br />
<br />
<br />
*Cantilevered Abutment (see semi-gravity retaining wall below)<br />
<br />
<br />
[[File:Fig 719.png|600px|framed|center|Figure 2. reinforced cantilever abutment wall]]<br />
<br />
<br />
<br />
*Integral and Semi-Integral Abutments – Integral and semi-integral abutments are detailed in the MDOT Bridge Design Guides 6.20.04, 6.20.04B, 6.20.04D.<br />
<br />
Integral abutments are designed to be supported on a single row of piles that are oriented with their webs parallel to the bridge reference line to allow weak axis bending to accommodate superstructure articulation due to thermal gradient and live loading. Splices for piles in integral abutments must be complete joint penetration (CJP). Alternative mechanical splicer channels are not permitted.<br />
<br />
==[[#Anchored Wall|Anchored Wall]]==<br />
<br />
Anchored walls can consist of ground anchors or tie backs. Verification load testing and proof load testing of the ground anchors is typically performed on all anchors to ensure the actual lateral pullout resistance is within the design tolerances. The verification load testing procedures will be detailed in the contract documents.<br />
<br />
<br />
<br />
==[[#Mechanically Stabilized Earth Wall| Mechanically Stabilized Earth Wall]]==<br />
<br />
Below are the basic components of a mechanically stabilized earth (MSE) wall system and a summary of items to review during construction:<br />
<br />
:A.Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed. Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.<br />
<br />
:B.Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office. <br />
Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.<br />
<br />
:C. Wire Facing Panels – Wire facing panels are typically specified for temporary MSE walls during Stage I construction. The walls end up being buried into the final structure and are not removed. The wire facing panels in this temporary application are usually black steel due to the short duration of use.<br />
<br />
:D. Soil Reinforcement – MDOT permits the use of steel strip-type (bar or welded wire fabric ladder) reinforcement. Soil reinforcement must be placed as close to perpendicular from the wall face as practical. The reinforcement is permitted to be skewed around piling or other obstructions, but should be done so to not only reduce the skew, but also the number of skewed reinforcement strips. Reinforcement should not be in contact with other reinforcement. For skewed reinforcement soil must be placed between overlapping reinforcement. <br />
<br />
:E. Bolts – Bolts are typically positioned with the head at the bottom side of the connection lug and the washer and nut on the top side. This allows the inspector to visually inspect that the washers and nuts have been installed as the reinforced soil is constructed behind the wall. <br />
<br />
:F. Concrete Facing Panel Joint Material – Geotextile fabric is used to prevent soil particles from moving through the concrete facing panels. If the facing panel joints start to open up then the contractor should double the geotextile over the joints in question to provide additional protection.<br />
<br />
:G. Backfill for Reinforced Soil Mass – Granular soil, typically Granular Material Class II, whic is free draining and meets the required strength and electro-chemical properties. This material must be tested and approved prior to placement.<br />
<br />
:H. Leveling Pad – Is a non-reinforced concrete pad that provides a level starting point for constructing the precast concrete facing panels. A leveling pad is not needed for a wire faced MSE wall.<br />
<br />
:I. Impervious Membrane – A polyvinylchloride (PVC) liner that prevents chloride laden runoff from penetrating into the reinforced soil mass and corroding the steel reinforcement. The liner must be shingle-lapped or seam welded and is positioned to slope away from the front of the wall and extend a minimum distance beyond the end of the soil reinforcement.<br />
<br />
:J. CIP Copings – These copings are typically used as closure pours, but can also run up to 20 feet in length and can overlap adjacent panels without the need for a bond breaker. Expansion joint material is needed when butting CIP coping up to precast coping.<br />
<br />
:K. Foundation Underdrains – Are strategically placed to transport water from the reinforced soil mass to a location far away from the wall. MSE walls are generally not designed for hydrostatic pressure. Foundation underdrains are to be installed at the locations indicated on the plans. The lower foundation underdrains are to be located as low as possible but still drain to either a ditch or a drainage structure.<br />
<br />
MSE Wall Construction Considerations<br />
<br />
*During the wet cure for the concrete bridge deck the water coming off of the deck needs to be collected and discharged away from the MSE wall. Water runoff from the deck may saturate the MSE backfill and cause wall movement.<br />
<br />
*Groundwater needs to be controlled to prevent hydrostatic forces from acting on the wall. If groundwater is encountered during construction the location/number of foundation underdrains may need to be reevaluated.<br />
<br />
*Compaction of the Select Backfill and any subgrade undercuts is important in order to limit any future settlement of the MSE wall fill.<br />
<br />
[[File:Fig 719.png|600px|framed|center|Figure 1. MSE wall]]<br />
<br />
<br />
==[[#Non-Gravity Cantilevered Retaining Wall| Non-Gravity Cantilevered Retaining Wall]]==<br />
<br />
Examples of on-gravity cantilevered retaining walls are listed below:<br />
*Tangent piles or drilled shafts;<br />
*Drilled shafts or auger-cast piles spanned by structural facing (lagging, panels or shotcrete);<br />
*Steel sheet piling (see Section 704 – Steel Sheet Piling and Cofferdams).<br />
<br />
==[[#Rigid-Gravity and Semi-Gravity Retaining Wall|Rigid-Gravity and Semi-Gravity Retaining Wall]]==<br />
<br />
[[File:Fig719-4.png|600px|framed|center|Figure 3. Reinforced concrete counterfort semi-gravity wall]]<br />
<br />
<br />
<br />
[[File:Fig719-5.png|600px|framed|center|Figure 4. Reinforced concrete cantilever semi-gravity wall.]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=718_-_Drilled_Shafts&diff=3878718 - Drilled Shafts2014-11-12T19:21:26Z<p>HarrisR18: /* Rigid-Gravity and Semi-Gravity Retaining Wall */</p>
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<div><br />
<center><span STYLE="font: 60pt arial;">'''718'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Drilled Shafts'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 718]</center><br />
<br />
<br />
==[[#GENERAL|GENERAL]]==<br />
<br />
Drilled shaft foundations are also referred to caissons, drilled piers, or bored piles, and consist of circular shafts of varying diameter, drilled to a design depth, reinforced with a steel rebar cage, and filled with concrete. Drilled shaft foundations can support large loads, and are used when driving steel piles is not feasible, or surrounding structures or utilities are too sensitive to survive the vibrations from steel foundation pile driving operations. Like steel foundation piles, loads from the superstructure transfer into the drilled shafts, which transfer loads to soil layers through side friction, end bearing, or a combination of the two. Drilled shafts are used for bridge foundations, and other ancillary structure foundations such as sign cantilevers and trusses, and signal strain poles.<br />
<br />
Drilled shafts can be constructed in the dry, or in the wet, and can also include a steel casing.<br />
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===[[#DRY CONSTRUCTION METHOD|DRY CONSTRUCTION METHOD]]===<br />
<br />
Dry construction methods are generally used when the water table is below the bottom of the shaft, and the existing soils are stiff enough as not to sloughing or caving into the hole during drilling operations. Any accumulated water greater than 3 inches at the bottom of the shaft must be pumped out prior to rebar and concrete placement, and during concrete placement, water cannot flow into the shaft at a rate greater than 12 inches within 1 hour.<br />
<br />
Typical issues with dry construction methods are if the soils are unstable, or the water table is too high, but the Contractor attempts to force dry shaft construction. In this scenario, soil caving problems will lead to soil inclusions in the shaft concrete, affecting the shaft integrity. If any problems like this arise during construction, contact the Geotechnical Services area.<br />
<br />
Another issue to watch for is if the Contractor leaves the excavation open for too long prior to reinforcement cage and concrete placement. Soils that were capable of maintaining hole stability during the drilling operations may shrink or swell over time and slowly lose that ability, resulting in caving leading to soil inclusions in the shaft concrete affecting the shaft integrity.<br />
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<br />
===[[#WET CONSTRUCTION METHOD|WET CONSTRUCTION METHOD]]===<br />
<br />
Wets construction methods are generally used where a dry excavation cannot be maintained during drilling, or shaft concrete placement. This typically occurs in areas of high water tables, and sandy soils that would otherwise slough or cave into the shaft during drilling operations. Water or a polymer slurry is used to contain water seepage, and maintain stability of the shaft excavation. Polymer slurry must be de-sanded and cleaned if used. Temporary surface casings are typically used to ensure shaft alignment. The rebar cage is lowered into the shaft, and concrete is placed using a tremie tube, or concrete pump capable of reaching the bottom of the shaft.<br />
<br />
Typical issues with wet construction methods are inexperienced Contractors that do not understand the mechanics of polymer slurry construction, and the need to ensure proper suspension of sediment and cuttings for removal, and control of caving. This can lead to shafts not being properly cleaned of sediment, resulting in voids, or inclusions in the concrete, affecting the shaft integrity.<br />
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===[[#DRY TEMPORARY CASING METHOD|DRY TEMPORARY CASING METHOD]]===<br />
<br />
Dry temporary cased construction methods are generally used where caving soils occur, over soil or rock deformations are expected, but the casing can maintain a dry and stable excavation. The casing is advanced simultaneously with the excavation. After placement of the rebar cage, the casing is then withdrawn slowly during concrete placement until removed at the top of shaft.<br />
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===[[#WET TEMPORARY CASING METHOD|WET TEMPORARY CASING METHOD]]===<br />
<br />
Wet temporary cased construction methods are generally used where caving soils occur, and a dry excavation cannot be maintained, the soils are too permeable, and the groundwater is higher than the bottom of the shaft. The casing is advanced simultaneously with the excavation, but it is important that no drilling occur outside the casing through any caving soil layers. After placement of the rebar cage, the concrete is placed using a tremie tube or concrete pump capable of reaching the bottom of the shaft. The water in the casing is not to be pumped out, rather it is to be displaced by the concrete placement.<br />
<br />
It is important to ensure the Contractor maintains a positive fluid pressure head in the shaft above the ground water elevation, or material from the side walls of the shaft will be pulled into the bottom of the shaft.<br />
<br />
For both the wet and dry casing methods, the casing is typically installed in a telescoping fashion, where the top casings may be larger than the drilled shaft diameter as called for on the plans. The depth of the hole will also dictate how many sections of casing are to be used. Ensure the contractor does not telescope the casings down to a diameter less than the design diameter as shown on the plans.<br />
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<br />
==[[#MATERIALS|MATERIALS]]==<br />
<br />
===[[#Concrete, Grade S2, and Grade T|Concrete, Grade S2, and Grade T]]===<br />
<br />
Ensure concrete materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf section 701] of the Standard Specifications for Construction, except modifications for the slump requirements per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction. Concrete Grade S2 is to be used for dry construction, and Concrete Grade T is to be used for wet construction.<br />
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===[[#Steel Reinforcement|Steel Reinforcement]]===<br />
<br />
Ensure steel reinforcement bars are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/905%20Steel%20Reinforcement.pdf section 905] of the Standard Specifications for Construction. Check the plans and specifications for epoxy rebar requirements.<br />
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===[[#Steel Casing|Steel Casing]]===<br />
<br />
Ensure steel casing materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/919%20Perm%20Traf%20Signs,%20Supports.pdf section 919.10] of the Standard Specifications for Construction. Permanent casing will also require Buy America certification, temporary casings will not, unless left in place.<br />
<br />
Review the plans for temporary casing-left in place cut off elevations. The Contractor is required to provide casing to be smooth and watertight, and capable of withstanding the pressure of concrete and the lateral earth pressures exerted down the length of the shaft. Ensure the outside diameter of the casing is at least equal to the diameter of the shaft as called for on the plans.<br />
<br />
Temporary casings should come equipped with hook holes, or other attachments to aid in the removal as the concrete pour advances. The concrete placement is to be complete prior to complete removal of the casing. The casings should be removed slowly, and with pull forces being in line with the shaft axis. Do not allow the contractor to pull shaft casings with equipment offset from the centerline of the shaft, as this will either disrupt the already placed concrete, or case caving of soil materials into the plastic concrete.<br />
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<br />
===[[#Polymer slurry|Polymer slurry]]===<br />
<br />
When wet construction methods are required, polymer type slurry is required. Bentonite slurry is prohibited. Ensure the polymer slurry is of sufficient specific gravity to ensure stability of the excavation during drilling operations, and allows for concrete placement. The Geotechnical Services area will typically review and approve the Contractor’s proposed polymer slurry materials.<br />
<br />
Ensure any polymer slurry used meets the requirements of [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Table 718-1] from the Standard Specifications for Construction. Ensure the Contractor maintains the height of polymer slurry to prevent the side walls of the excavation from caving, and the bottom from heaving.<br />
<br />
Ensure the contractor pre-mixes the polymer slurry materials with clean, fresh water, and allow time for hydration prior to pumping into shaft excavation. The polymer slurry should be agitated to prevent setting up in the shaft.<br />
<br />
If de-sanding is required, ensure the Contractor provides the appropriate equipment. Prior to placement of shaft concrete, take polymer slurry samples with a polymer slurry test kit to determine if heavily contaminated polymer slurry at the bottom of the shaft is to be removed. Ensure the Contractor controls and collects polymer slurry exiting the excavation as the concrete displaces the volume. Review the plans for polymer slurry handling and disposal requirements.<br />
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<br />
==[[#CONSTRUCTION|CONSTRUCTION]]==<br />
<br />
===[[#EQUIPMENT|Equipment]]===<br />
<br />
Ensure the contractor is using appropriate equipment to drill the shafts given the site conditions reported in the soil borings, and geotechnical subsurface exploration report. See Figure 1 for a typical drill rig set up. The major components of drill rig include:<br />
<br />
* Crawler or truck mounted auger<br />
* Auger of the appropriate type – rock auger, single or double flight earth auger. See Figure 2 for a double flight earth auger, see Figure 3 for a single flight rock auger.<br />
* Muck or clean out bucket – see Figures 4 and 5 for a muck bucket example.<br />
* Rock core barrel – see Figure 6 for a rock core barrel example.<br />
[[File:Fig 718-1.png|600px|framed|center|Figure 1. Typical drill rig set up]]<br />
<br />
[[File:Fig 718-2.png|600px|framed|center|Figure 2. Double flight earth auger]]<br />
<br />
[[File:Fig 718-3.png|600px|framed|center|Figure 3. Single flight rock auger]]<br />
<br />
[[File:Fig 718-4.png|600px|framed|center|Figure 4. Muck bucket]]<br />
<br />
[[File:Fig 718-5.png|600px|framed|center|Figure 5. Muck bucket bottom]]<br />
<br />
[[File:Fig 718-6.png|600px|framed|center|Figure 6. Soft rock core barrel]]<br />
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<br />
===[[#DRILLED SHAFT CONSTRUCTION|DRILLED SHAFT CONSTRUCTION]]===<br />
To track drilled shaft operations, use MDOT [http://mdotcf.state.mi.us/public/webforms/public/1988.pdf form 1988] – DRILLED SHAFT INSPECTION RECORD FOR HIGHWAY SIGNS, LUMINAIRES, AND TRAFFIC SIGNALS.<br />
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====[[#Prior to Drilled Shaft Operations|Prior to Drilled Shaft Operations]]====<br />
<br />
The Contractor is required to submit a Drilled Shaft Installation plan, per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.A] of the Standard Specifications for Construction. This plan is to detail all equipment to be used, the construction sequence, rebar and concrete placement, etc. The Geotechnical Services area will review and approve the Drilled Shaft Installation plan. Review and understand the following:<br />
<br />
* Proposed equipment, including cranes, drills, augers, core barrels, bailing buckets, cleaning equipment, polymer slurry pumps and cleaning equipment, tremie tubes or concrete pumps, and casing.<br />
<br />
* Construction sequence, including methods to ensure a stable excavation, and removal of materials at the bottom of the shaft prior to rebar cage placement.<br />
<br />
* Shaft excavation methods, including proposed excavation methods through supporting and caving soil layers.<br />
<br />
* Method to mix, circulate and de-sand polymer slurry for wet construction methods.<br />
<br />
* Reinforcement placement, including support and centering methods.<br />
<br />
* Concrete placement, including free fall, tremie, or concrete pumping procedures.<br />
<br />
* Methods to prevent drilled shaft excavation spoils from entering waterways, wetlands and floodplains.<br />
<br />
* Fall protection plan conforming to MIOSHA Construction Safety Standards, including a rescue plan for shafts with a diameter of at least 30 inches, and at least 6 feet deep. This must be in place prior to commencement of any drilling operations.<br />
<br />
* Conformance with shaft diameter and rebar requirements based on details shown in the plans.<br />
<br />
Ensure the Contractor has brought all of the proposed equipment as stated in their approved Drilled Shaft Installation plan.<br />
<br />
If the shaft is to be constructed during the wet method, verify if the Contractor is allowed to use water as the drilling fluid, or if polymer slurry is required. Typically, Contractors will want to use water, but water will not prevent caving in deeper shafts. The use of bentonite slurry is prohibited.<br />
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====[[#During Drilling Operations|During Drilling Operations]]====<br />
<br />
Ensure the Contractor performs the following:<br />
<br />
* Check the drilled shaft dimensions and the alignment with reference stakes and plumb bob.<br />
<br />
* Check the dimensions and alignment of the casing inserted in the excavation.<br />
<br />
* Insert a rigid rod assembly with several 90-degree offsets equal to the shaft diameter into the shaft excavation to ensure required diameter.<br />
<br />
* Construction Method Log: The Contractor is required to submit a daily construction method log during drilled shaft excavation and construction per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.5] of the Standard Specifications for Construction. Ensure the following information is shown on the logs:<br />
<br />
* Start dates and completions dates<br />
<br />
* Drilled shaft identification number<br />
<br />
* Location<br />
<br />
* Actual top and bottom elevation of drilled shaft <br />
<br />
* Shaft diameter<br />
<br />
* Final centerline location at top of shaft<br />
<br />
* Variation of drilled shaft from plumb<br />
<br />
* Top and bottom elevation of any permanent casing<br />
<br />
* Description of each soil and rock material encountered during excavating and the top and bottom depths or elevations<br />
<br />
* Depth drilled into bearing stratum<br />
<br />
* Top and bottom elevations of obstructions encountered<br />
<br />
* Amount of obstruction time<br />
<br />
* Depth or elevation of encountered seepage of groundwater<br />
<br />
* Actual volume of concrete placed, compared to the theoretical concrete volume to detect any large void or intrusions of extraneous materials<br />
<br />
* Any remarks to better describe operations.<br />
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Ensure the Contractor maintains the required drilling fluid or polymer slurry levels to prevent caving.<br />
<br />
Construction tolerances – Ensure the drilled shafts are within 3 inches horizontally of centerlines shown on the plans, and the drilled shaft is no more than 1 percent out of plumb, as measured horizontally from the actual center of the shaft at the shaft design top elevation.<br />
<br />
Ensure the Contractor cleans each shaft so at least 50% of the base contains less than ½ inch of sediment. The shaft bottom should have no more than 1 ½ inches of debris above the required bottom elevation. Use a weighted tape to check the bottom of the shaft excavation for debris.<br />
<br />
Marks on the Kelly Bar should be checked to ensure the required bottom of shaft elevation. Monitor the excavation to ensure the expected amount of materials are removed by the auger, if not, caving soils are present.<br />
<br />
Ensure the top elevation of the drilled shaft is from +1 inch to -3 inches from the top of the shaft elevation shown on the plans. For shafts outside of this tolerance range, contact the Geotechnical Services area for recommendations as to corrections. [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Subsection 718.03.C.4] of the Standard Specifications for Construction dictates contractual obligations of the contractor to correct out of tolerance shafts.<br />
<br />
Verify the soil cuttings as they are removed from the auger, and notify the Geotechnical Services area if soil cuttings appear different than those shown on the soil borings. Ensure the Contractor stores soil cuttings away from the drill shaft locations.<br />
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===[[#Obstruction Removal|Obstruction Removal]]===<br />
<br />
Obstructions are to be removed per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.F.2] of the Standard Specifications for Construction. Obstructions may include old concrete foundations, abandoned utilities, or boulders and cobbles. Ensure the Contractor uses tools and procedures as approved by the Geotechnical Services Section to remove the obstructions. Special procedures and tools include:<br />
<br />
* Chisels<br />
* Boulder breakers<br />
* Core barrels<br />
* Air tools<br />
* Hand excavation<br />
* Temporary casing<br />
* Enlarging the drilled shaft diameter<br />
<br />
Removal of obstructions that require special equipment or tools will be measured and paid for as extra work per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.04.D] of the Standard Specifications or Construction. A budget amount will be established to pay for removing obstructions. If the Contractor and the Engineer cannot agree on a lump sum price, the Engineer will direct the work to be done on a force account basis.<br />
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===[[#Placing Steel Reinforcement|Placing Steel Reinforcement]]===<br />
<br />
Check the plans and specifications to verify the Contractor is using the correct size longitudinal bars and lateral or spiral reinforcement, and correct bar lap lengths if used.<br />
<br />
Reinforcing cage – maintain the top of the reinforcing steel cage no greater than 1 inch above, and no greater than 3 inches below the required position. Measure the distance between the top of shaft and the top of reinforcing cage with a straight edge, and direct the Contractor to correct the position if out of tolerance.<br />
<br />
Ensure the Contractor provides a fully assembled steel reinforcement cage for inspection at least two working days before the start of construction. Ensure all longitudinal bars and lateral or spiral reinforcement is properly tied. Ensure plastic spacers are tied at the quarter points around the cage perimeter, but no greater than 30 inches apart.<br />
<br />
Ensure the plastic spacers are spaced at intervals no greater than 5 feet along the length of the cage for #8 bar or smaller, and 10’ for bars larger than #8 to ensure a minimum annular space of 3 inches between the outside of the cage and the side of the excavation or casing. See Figure 7 for an example of plastic spacers on the rebar cage.<br />
<br />
[[File:Fig 718-7.png|600px|framed|center|Figure 7. Rebar cage spacers]]<br />
<br />
Ensure the Contractor does not use concrete blocks, wood blocks, or metal chairs as spacers, as these will not retain the required spacing, and will shift out of position during cage lowering, or during the concrete pour.<br />
<br />
The Contractor may use concrete blocks at the bottom of the shaft to maintain concrete cover over the reinforcement. Ensure the Contractor picks and lowers the reinforcement cage into the shaft in a controlled manner, as not to cause racking or distorting of the tied cage. See Figure 8 for a typical reinforcement cage being lowered into the completed shaft.<br />
<br />
[[File:Fig 718-8.png|600px|framed|center|Figure 8. Rebar cage being lowered into complete shaft]]<br />
<br />
Ensure the Contractor holds down the cage to control vertical displacement during concrete placement or casing extraction.<br />
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===[[#Placing Concrete|Placing Concrete]]===<br />
<br />
Ensure the Contractor places concrete as soon as possible after the excavation and reinforcement cage placement. If too much time has elapsed, loose or soft materials may accumulate at the bottom of the shaft, thus affecting the structural integrity. If this happens, direct the Contractor to remove the reinforcement cage, and remove loose or soft materials.<br />
<br />
Use lighting to inspect the reinforcement cage and side of excavation for dry method construction. Ensure loose materials and groundwater is removed prior to placement of concrete.<br />
<br />
Inspect by probing and measuring the shaft for wet method construction. The Contractor is required to place the concrete in one continuous operation starting from the bottom of the shaft. Once concrete reaches the top of the shaft, inspect the concrete for contaminants, and direct the Contractor to continue concrete placement until good quality concrete flows over the top of the shaft. The concrete should not be vibrated. Ensure the Contractor uses a sump or channel adjacent to the shaft to transmit displaced fluid and concrete away from the shaft opening. If polymer slurry is used, ensure the Contractor collects and disposes of the drilling fluids or polymer slurry appropriately. <br />
<br />
Track the volume of concrete going into the shafts based on tickets, and perform theoretical concrete volume calculation based on the diameter and the length of the shaft. If the numbers vary by too much, it is possible a void is present.<br />
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<br />
====[[#Free Fall Concrete Placement|Free Fall Concrete Placement]]====<br />
<br />
Free fall concrete placement can only be done in a dry shaft excavation.<br />
<br />
The falling concrete cannot strike the sides of the excavation or the reinforcing cage. Ensure the Contractor uses a centering drop chute at least 3 feet long. If concrete strikes the sides of the excavation or the reinforcing cage, direct the Contractor to reduce the height of free fall, the rate of concrete flow, or both. The free fall height limit is 80 feet.<br />
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<br />
====[[#Tremie Tube Concrete Placement|Tremie Tube Concrete Placement]]====<br />
<br />
Ensure the Contractor is using a tremie tube of at least 10 inches in diameter. Inspect the bottom of the Contractor’s tremie tube to ensure there is a bottom plate, valve, or plug so no water can get into the tube and contaminate the concrete prior to placement.<br />
<br />
The tremie tube must be placed at the bottom of the shaft, and once the plate or plug is removed, or valve is opened, ensure the Contractor keeps the discharge end 5 feet to 10 feet immersed in concrete before raising the tremie tube.<br />
<br />
It is ideal for the concrete to be placed continuously until complete, however, should the Contractor need to withdraw the tremie tube from the concrete, ensure the discharge end is re-sealed, charged with concrete, and inserted back into the concrete at least 10 feet before continuing with the concrete placement.<br />
<br />
For cased shafts, it is important discharge keep a head of concrete above the bottom of casing to be removed, and then remove the casing slowly, to allow the concrete to fill the annular space created by the case thickness. If the concrete level goes down during case extraction, direct the Contractor to stop the extraction, and add more concrete.<br />
<br />
The concrete must be placed in a timely fashion, so the slump does not go below 4”, as the concrete will not properly envelope the rebar cage, or fill the shaft to the required diameter. See Figure 9 for an example of concrete not filling the required shaft diameter.<br />
<br />
Allow the concrete to continue flowing at the top of the shaft, until quality concrete displaces all drilling fluid. Drilling fluid at the top of the shaft may have to be pumped of.<br />
<br />
Ensure the Contractor provides a hand floated surface finish at the top of the shaft concrete per [http://mdotcf.state.mi.us/public/specbook/files/2012/706%20Str%20Conc%20Construction.pdf subsection 706.06.M.2] of the Standard Specifications for Construction.<br />
<br />
* Do not remove the tremie tube from the concrete to take concrete QA samples.<br />
<br />
[[File:Fig 718-9.png|600px|framed|center|Figure 9. Improper concrete placement]]<br />
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====[[#Pumped Concrete Placement|Pumped Concrete Placement]]====<br />
<br />
Concrete can be pumped for by dry and wet shaft excavations, however, for use in wet excavations, ensure the Contractor provides a pump discharge tube with watertight joints.<br />
<br />
Pumped concrete is very similar to tremie concrete in terms of operations. The main issue to watch is the sway and movement of the pumping pipes during concrete placement. Ensure the Contractor guides or anchors the pumping pipes as to not disturb already placed fresh concrete.<br />
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===[[#POST CONSTRUCTION INTEGRITY TESTING|POST CONSTRUCTION INTEGRITY TESTING]]===<br />
<br />
Check the plans and specifications for any type of post construction integrity testing to be done on the completed shaft. There are several methods of non-destructive testing:<br />
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<br />
====[[#Pulse Echo Integrity Testing|Pulse Echo Integrity Testing]]====<br />
<br />
This type of test involves setting an ultrasonic transducer on the surfaces of the concrete, which send wave pulses through the material. Wave pulses will continue through solid concrete until a concrete to air interface, at which time the pulse is reflected back to the transducer, and a depth can be measured. In the presence of voids, the wave would reflect back sooner than expected given the overall thickness of the materials.<br />
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<br />
====[[#Cross Hole Sonic Logging|Cross Hole Sonic Logging]]====<br />
<br />
This type of test involves the attachment of steel access tubes to the vertical cage rebar prior to concrete placement. The concrete is then placed and allowed to cure. Immediately after concrete placement, the steel access tubes are to be filled with water to protect from concrete infiltration. After curing, a sound source and a received are lowered into the steel access tubes, and while keeping them at the same elevation, sonic pulses are emitted from the sound source, and the wave generated is picked up by the receiver. Based on the speed the wave propagates through the material, the receiver maps the integrity of the surrounding concrete, and voids are reported where the wave returns to the receiver at faster rates than sound areas.<br />
<br />
These types of tests are typically performed by a skilled technician, or MDOT prequalified consultant. The [http://www.michigan.gov/mdot/0,4616,7-151-9623_26663_27303-269622--,00.html Geotechnical Services Section] will be present during integrity testing to help analyze and interpret results.<br />
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<br />
====[[#Coring|Coring]]====<br />
<br />
Coring is a destructive test to remove cores of concrete from the finished shaft, and perform testing to determine concrete quality. Coring may also be done when voids are identified during non-destructive tests to reach the detected void. Grout can then be used to fill the void, and the core holes.<br />
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<br />
==[[#MEASUREMENT AND PAYMENT|MEASUREMENT AND PAYMENT]]==<br />
<br />
<span style="color: red"> -Reserved- </span><br />
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[[Category:Construction Manual]]<br />
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<center><span STYLE="font: 60pt arial;">'''719'''</span></center><br />
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<center><span STYLE="font: 40pt arial;">'''Earth Retaining Structures'''</span></center><br />
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<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/719%20Earth%20Retaining%Structures.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 719]</center><br />
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==[[#General|General]]==<br />
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Below is a list with definitions of common earth retaining structures utilized by MDOT:<br />
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*Abutment – A structure located at the end of a bridge span that supports the vertical loads from the bridge superstructure, and resists lateral loads from fill material on which the roadway rests immediately adjacent to the bridge.<br />
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*Anchored Wall – An earth retaining system typically composed of the same elements as non-gravity cantilevered walls and that derive additional lateral resistance from one or more tiers of anchors.<br />
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*Mechanically Stabilized Earth (MSE) Wall – A soil-retaining system, employing either strip or grid-type, metallic, or polymeric tensile reinforcements in the soil mass, and a facing element that is either vertical or nearly vertical.<br />
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*Segmental Block Retaining Wall – A soil-retaining system, typically employing polymeric tensile reinforcements in the soil mass attached to a facing element that consists of segmental blocks. Segmental blocks are typically dry cast blocks.<br />
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*Modular Block Retaining Wall – A soil-retaining system that consists of modular blocks stacked to form a gravity wall with a vertical or nearly vertical face. Modular blocks are typically large precast concrete blocks.<br />
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*Non-Gravity Cantilever Retaining Wall – A soil-retaining system that derives lateral resistance through embedment of vertical wall elements and supports retained soil with facing elements. Vertical wall elements may consist of discrete elements (piles, drilled shafts, etc.) or a continuous system (sheet piles, tangent drilled shafts, etc.).<br />
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*Rigid Gravity and Semi-Gravity Retaining Wall – A structure that provides lateral support for a mass of soil and that owes its stability primarily to its own weight and to the weight of any soil located directly above its base.<br />
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Some of these elements may not be detailed on the plans, and may require shop drawing submittals for approval. See 707 of the MDOT Construction Manual for shop drawing requirements.<br />
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==[[#Abutments|Abutments]]==<br />
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MDOT utilizes the following types of abutments:<br />
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*Curtainwall Abutment (see rigid-gravity retaining wall below);<br />
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[[File:Fig 719.png|600px|framed|center|Figure 1. Unreinforced concrete rigid-gravity wall, or curtain wall abutment]]<br />
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*Cantilevered Abutment (see semi-gravity retaining wall below)<br />
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[[File:Fig 719.png|600px|framed|center|Figure 2. reinforced cantilever abutment wall]]<br />
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*Integral and Semi-Integral Abutments – Integral and semi-integral abutments are detailed in the MDOT Bridge Design Guides 6.20.04, 6.20.04B, 6.20.04D.<br />
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Integral abutments are designed to be supported on a single row of piles that are oriented with their webs parallel to the bridge reference line to allow weak axis bending to accommodate superstructure articulation due to thermal gradient and live loading. Splices for piles in integral abutments must be complete joint penetration (CJP). Alternative mechanical splicer channels are not permitted.<br />
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==[[#Anchored Wall|Anchored Wall]]==<br />
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Anchored walls can consist of ground anchors or tie backs. Verification load testing and proof load testing of the ground anchors is typically performed on all anchors to ensure the actual lateral pullout resistance is within the design tolerances. The verification load testing procedures will be detailed in the contract documents.<br />
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==[[#Mechanically Stabilized Earth Wall| Mechanically Stabilized Earth Wall]]==<br />
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Below are the basic components of a mechanically stabilized earth (MSE) wall system and a summary of items to review during construction:<br />
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:A.Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed. Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.<br />
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:B.Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office. <br />
Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.<br />
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:C. Wire Facing Panels – Wire facing panels are typically specified for temporary MSE walls during Stage I construction. The walls end up being buried into the final structure and are not removed. The wire facing panels in this temporary application are usually black steel due to the short duration of use.<br />
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:D. Soil Reinforcement – MDOT permits the use of steel strip-type (bar or welded wire fabric ladder) reinforcement. Soil reinforcement must be placed as close to perpendicular from the wall face as practical. The reinforcement is permitted to be skewed around piling or other obstructions, but should be done so to not only reduce the skew, but also the number of skewed reinforcement strips. Reinforcement should not be in contact with other reinforcement. For skewed reinforcement soil must be placed between overlapping reinforcement. <br />
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:E. Bolts – Bolts are typically positioned with the head at the bottom side of the connection lug and the washer and nut on the top side. This allows the inspector to visually inspect that the washers and nuts have been installed as the reinforced soil is constructed behind the wall. <br />
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:F. Concrete Facing Panel Joint Material – Geotextile fabric is used to prevent soil particles from moving through the concrete facing panels. If the facing panel joints start to open up then the contractor should double the geotextile over the joints in question to provide additional protection.<br />
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:G. Backfill for Reinforced Soil Mass – Granular soil, typically Granular Material Class II, whic is free draining and meets the required strength and electro-chemical properties. This material must be tested and approved prior to placement.<br />
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:H. Leveling Pad – Is a non-reinforced concrete pad that provides a level starting point for constructing the precast concrete facing panels. A leveling pad is not needed for a wire faced MSE wall.<br />
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:I. Impervious Membrane – A polyvinylchloride (PVC) liner that prevents chloride laden runoff from penetrating into the reinforced soil mass and corroding the steel reinforcement. The liner must be shingle-lapped or seam welded and is positioned to slope away from the front of the wall and extend a minimum distance beyond the end of the soil reinforcement.<br />
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:J. CIP Copings – These copings are typically used as closure pours, but can also run up to 20 feet in length and can overlap adjacent panels without the need for a bond breaker. Expansion joint material is needed when butting CIP coping up to precast coping.<br />
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:K. Foundation Underdrains – Are strategically placed to transport water from the reinforced soil mass to a location far away from the wall. MSE walls are generally not designed for hydrostatic pressure. Foundation underdrains are to be installed at the locations indicated on the plans. The lower foundation underdrains are to be located as low as possible but still drain to either a ditch or a drainage structure.<br />
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MSE Wall Construction Considerations<br />
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*During the wet cure for the concrete bridge deck the water coming off of the deck needs to be collected and discharged away from the MSE wall. Water runoff from the deck may saturate the MSE backfill and cause wall movement.<br />
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*Groundwater needs to be controlled to prevent hydrostatic forces from acting on the wall. If groundwater is encountered during construction the location/number of foundation underdrains may need to be reevaluated.<br />
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*Compaction of the Select Backfill and any subgrade undercuts is important in order to limit any future settlement of the MSE wall fill.<br />
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[[File:Fig 719.png|600px|framed|center|Figure 1. MSE wall]]<br />
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==[[#Non-Gravity Cantilevered Retaining Wall| Non-Gravity Cantilevered Retaining Wall]]==<br />
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Examples of on-gravity cantilevered retaining walls are listed below:<br />
*Tangent piles or drilled shafts;<br />
*Drilled shafts or auger-cast piles spanned by structural facing (lagging, panels or shotcrete);<br />
*Steel sheet piling (see Section 704 – Steel Sheet Piling and Cofferdams).<br />
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==[[#Rigid-Gravity and Semi-Gravity Retaining Wall|Rigid-Gravity and Semi-Gravity Retaining Wall]]==<br />
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[[File:Fig719.png|600px|framed|center|Figure 3. Reinforced concrete counterfort semi-gravity wall]]<br />
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[[File:Fig719.png|600px|framed|center|Figure 4. Reinforced concrete cantilever semi-gravity wall.]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=718_-_Drilled_Shafts&diff=3877718 - Drilled Shafts2014-11-12T19:20:43Z<p>HarrisR18: </p>
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<div><br />
<center><span STYLE="font: 60pt arial;">'''718'''</span></center><br />
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<center><span STYLE="font: 40pt arial;">'''Drilled Shafts'''</span></center><br />
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<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 718]</center><br />
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==[[#GENERAL|GENERAL]]==<br />
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Drilled shaft foundations are also referred to caissons, drilled piers, or bored piles, and consist of circular shafts of varying diameter, drilled to a design depth, reinforced with a steel rebar cage, and filled with concrete. Drilled shaft foundations can support large loads, and are used when driving steel piles is not feasible, or surrounding structures or utilities are too sensitive to survive the vibrations from steel foundation pile driving operations. Like steel foundation piles, loads from the superstructure transfer into the drilled shafts, which transfer loads to soil layers through side friction, end bearing, or a combination of the two. Drilled shafts are used for bridge foundations, and other ancillary structure foundations such as sign cantilevers and trusses, and signal strain poles.<br />
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Drilled shafts can be constructed in the dry, or in the wet, and can also include a steel casing.<br />
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===[[#DRY CONSTRUCTION METHOD|DRY CONSTRUCTION METHOD]]===<br />
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Dry construction methods are generally used when the water table is below the bottom of the shaft, and the existing soils are stiff enough as not to sloughing or caving into the hole during drilling operations. Any accumulated water greater than 3 inches at the bottom of the shaft must be pumped out prior to rebar and concrete placement, and during concrete placement, water cannot flow into the shaft at a rate greater than 12 inches within 1 hour.<br />
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Typical issues with dry construction methods are if the soils are unstable, or the water table is too high, but the Contractor attempts to force dry shaft construction. In this scenario, soil caving problems will lead to soil inclusions in the shaft concrete, affecting the shaft integrity. If any problems like this arise during construction, contact the Geotechnical Services area.<br />
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Another issue to watch for is if the Contractor leaves the excavation open for too long prior to reinforcement cage and concrete placement. Soils that were capable of maintaining hole stability during the drilling operations may shrink or swell over time and slowly lose that ability, resulting in caving leading to soil inclusions in the shaft concrete affecting the shaft integrity.<br />
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===[[#WET CONSTRUCTION METHOD|WET CONSTRUCTION METHOD]]===<br />
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Wets construction methods are generally used where a dry excavation cannot be maintained during drilling, or shaft concrete placement. This typically occurs in areas of high water tables, and sandy soils that would otherwise slough or cave into the shaft during drilling operations. Water or a polymer slurry is used to contain water seepage, and maintain stability of the shaft excavation. Polymer slurry must be de-sanded and cleaned if used. Temporary surface casings are typically used to ensure shaft alignment. The rebar cage is lowered into the shaft, and concrete is placed using a tremie tube, or concrete pump capable of reaching the bottom of the shaft.<br />
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Typical issues with wet construction methods are inexperienced Contractors that do not understand the mechanics of polymer slurry construction, and the need to ensure proper suspension of sediment and cuttings for removal, and control of caving. This can lead to shafts not being properly cleaned of sediment, resulting in voids, or inclusions in the concrete, affecting the shaft integrity.<br />
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===[[#DRY TEMPORARY CASING METHOD|DRY TEMPORARY CASING METHOD]]===<br />
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Dry temporary cased construction methods are generally used where caving soils occur, over soil or rock deformations are expected, but the casing can maintain a dry and stable excavation. The casing is advanced simultaneously with the excavation. After placement of the rebar cage, the casing is then withdrawn slowly during concrete placement until removed at the top of shaft.<br />
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===[[#WET TEMPORARY CASING METHOD|WET TEMPORARY CASING METHOD]]===<br />
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Wet temporary cased construction methods are generally used where caving soils occur, and a dry excavation cannot be maintained, the soils are too permeable, and the groundwater is higher than the bottom of the shaft. The casing is advanced simultaneously with the excavation, but it is important that no drilling occur outside the casing through any caving soil layers. After placement of the rebar cage, the concrete is placed using a tremie tube or concrete pump capable of reaching the bottom of the shaft. The water in the casing is not to be pumped out, rather it is to be displaced by the concrete placement.<br />
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It is important to ensure the Contractor maintains a positive fluid pressure head in the shaft above the ground water elevation, or material from the side walls of the shaft will be pulled into the bottom of the shaft.<br />
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For both the wet and dry casing methods, the casing is typically installed in a telescoping fashion, where the top casings may be larger than the drilled shaft diameter as called for on the plans. The depth of the hole will also dictate how many sections of casing are to be used. Ensure the contractor does not telescope the casings down to a diameter less than the design diameter as shown on the plans.<br />
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==[[#MATERIALS|MATERIALS]]==<br />
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===[[#Concrete, Grade S2, and Grade T|Concrete, Grade S2, and Grade T]]===<br />
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Ensure concrete materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf section 701] of the Standard Specifications for Construction, except modifications for the slump requirements per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction. Concrete Grade S2 is to be used for dry construction, and Concrete Grade T is to be used for wet construction.<br />
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===[[#Steel Reinforcement|Steel Reinforcement]]===<br />
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Ensure steel reinforcement bars are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/905%20Steel%20Reinforcement.pdf section 905] of the Standard Specifications for Construction. Check the plans and specifications for epoxy rebar requirements.<br />
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===[[#Steel Casing|Steel Casing]]===<br />
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Ensure steel casing materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/919%20Perm%20Traf%20Signs,%20Supports.pdf section 919.10] of the Standard Specifications for Construction. Permanent casing will also require Buy America certification, temporary casings will not, unless left in place.<br />
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Review the plans for temporary casing-left in place cut off elevations. The Contractor is required to provide casing to be smooth and watertight, and capable of withstanding the pressure of concrete and the lateral earth pressures exerted down the length of the shaft. Ensure the outside diameter of the casing is at least equal to the diameter of the shaft as called for on the plans.<br />
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Temporary casings should come equipped with hook holes, or other attachments to aid in the removal as the concrete pour advances. The concrete placement is to be complete prior to complete removal of the casing. The casings should be removed slowly, and with pull forces being in line with the shaft axis. Do not allow the contractor to pull shaft casings with equipment offset from the centerline of the shaft, as this will either disrupt the already placed concrete, or case caving of soil materials into the plastic concrete.<br />
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===[[#Polymer slurry|Polymer slurry]]===<br />
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When wet construction methods are required, polymer type slurry is required. Bentonite slurry is prohibited. Ensure the polymer slurry is of sufficient specific gravity to ensure stability of the excavation during drilling operations, and allows for concrete placement. The Geotechnical Services area will typically review and approve the Contractor’s proposed polymer slurry materials.<br />
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Ensure any polymer slurry used meets the requirements of [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Table 718-1] from the Standard Specifications for Construction. Ensure the Contractor maintains the height of polymer slurry to prevent the side walls of the excavation from caving, and the bottom from heaving.<br />
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Ensure the contractor pre-mixes the polymer slurry materials with clean, fresh water, and allow time for hydration prior to pumping into shaft excavation. The polymer slurry should be agitated to prevent setting up in the shaft.<br />
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If de-sanding is required, ensure the Contractor provides the appropriate equipment. Prior to placement of shaft concrete, take polymer slurry samples with a polymer slurry test kit to determine if heavily contaminated polymer slurry at the bottom of the shaft is to be removed. Ensure the Contractor controls and collects polymer slurry exiting the excavation as the concrete displaces the volume. Review the plans for polymer slurry handling and disposal requirements.<br />
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==[[#CONSTRUCTION|CONSTRUCTION]]==<br />
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===[[#EQUIPMENT|Equipment]]===<br />
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Ensure the contractor is using appropriate equipment to drill the shafts given the site conditions reported in the soil borings, and geotechnical subsurface exploration report. See Figure 1 for a typical drill rig set up. The major components of drill rig include:<br />
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* Crawler or truck mounted auger<br />
* Auger of the appropriate type – rock auger, single or double flight earth auger. See Figure 2 for a double flight earth auger, see Figure 3 for a single flight rock auger.<br />
* Muck or clean out bucket – see Figures 4 and 5 for a muck bucket example.<br />
* Rock core barrel – see Figure 6 for a rock core barrel example.<br />
[[File:Fig 718-1.png|600px|framed|center|Figure 1. Typical drill rig set up]]<br />
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[[File:Fig 718-2.png|600px|framed|center|Figure 2. Double flight earth auger]]<br />
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[[File:Fig 718-3.png|600px|framed|center|Figure 3. Single flight rock auger]]<br />
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[[File:Fig 718-4.png|600px|framed|center|Figure 4. Muck bucket]]<br />
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[[File:Fig 718-5.png|600px|framed|center|Figure 5. Muck bucket bottom]]<br />
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[[File:Fig 718-6.png|600px|framed|center|Figure 6. Soft rock core barrel]]<br />
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===[[#DRILLED SHAFT CONSTRUCTION|DRILLED SHAFT CONSTRUCTION]]===<br />
To track drilled shaft operations, use MDOT [http://mdotcf.state.mi.us/public/webforms/public/1988.pdf form 1988] – DRILLED SHAFT INSPECTION RECORD FOR HIGHWAY SIGNS, LUMINAIRES, AND TRAFFIC SIGNALS.<br />
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====[[#Prior to Drilled Shaft Operations|Prior to Drilled Shaft Operations]]====<br />
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The Contractor is required to submit a Drilled Shaft Installation plan, per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.A] of the Standard Specifications for Construction. This plan is to detail all equipment to be used, the construction sequence, rebar and concrete placement, etc. The Geotechnical Services area will review and approve the Drilled Shaft Installation plan. Review and understand the following:<br />
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* Proposed equipment, including cranes, drills, augers, core barrels, bailing buckets, cleaning equipment, polymer slurry pumps and cleaning equipment, tremie tubes or concrete pumps, and casing.<br />
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* Construction sequence, including methods to ensure a stable excavation, and removal of materials at the bottom of the shaft prior to rebar cage placement.<br />
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* Shaft excavation methods, including proposed excavation methods through supporting and caving soil layers.<br />
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* Method to mix, circulate and de-sand polymer slurry for wet construction methods.<br />
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* Reinforcement placement, including support and centering methods.<br />
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* Concrete placement, including free fall, tremie, or concrete pumping procedures.<br />
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* Methods to prevent drilled shaft excavation spoils from entering waterways, wetlands and floodplains.<br />
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* Fall protection plan conforming to MIOSHA Construction Safety Standards, including a rescue plan for shafts with a diameter of at least 30 inches, and at least 6 feet deep. This must be in place prior to commencement of any drilling operations.<br />
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* Conformance with shaft diameter and rebar requirements based on details shown in the plans.<br />
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Ensure the Contractor has brought all of the proposed equipment as stated in their approved Drilled Shaft Installation plan.<br />
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If the shaft is to be constructed during the wet method, verify if the Contractor is allowed to use water as the drilling fluid, or if polymer slurry is required. Typically, Contractors will want to use water, but water will not prevent caving in deeper shafts. The use of bentonite slurry is prohibited.<br />
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====[[#During Drilling Operations|During Drilling Operations]]====<br />
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Ensure the Contractor performs the following:<br />
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* Check the drilled shaft dimensions and the alignment with reference stakes and plumb bob.<br />
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* Check the dimensions and alignment of the casing inserted in the excavation.<br />
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* Insert a rigid rod assembly with several 90-degree offsets equal to the shaft diameter into the shaft excavation to ensure required diameter.<br />
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* Construction Method Log: The Contractor is required to submit a daily construction method log during drilled shaft excavation and construction per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.5] of the Standard Specifications for Construction. Ensure the following information is shown on the logs:<br />
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* Start dates and completions dates<br />
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* Drilled shaft identification number<br />
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* Location<br />
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* Actual top and bottom elevation of drilled shaft <br />
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* Shaft diameter<br />
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* Final centerline location at top of shaft<br />
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* Variation of drilled shaft from plumb<br />
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* Top and bottom elevation of any permanent casing<br />
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* Description of each soil and rock material encountered during excavating and the top and bottom depths or elevations<br />
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* Depth drilled into bearing stratum<br />
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* Top and bottom elevations of obstructions encountered<br />
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* Amount of obstruction time<br />
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* Depth or elevation of encountered seepage of groundwater<br />
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* Actual volume of concrete placed, compared to the theoretical concrete volume to detect any large void or intrusions of extraneous materials<br />
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* Any remarks to better describe operations.<br />
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Ensure the Contractor maintains the required drilling fluid or polymer slurry levels to prevent caving.<br />
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Construction tolerances – Ensure the drilled shafts are within 3 inches horizontally of centerlines shown on the plans, and the drilled shaft is no more than 1 percent out of plumb, as measured horizontally from the actual center of the shaft at the shaft design top elevation.<br />
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Ensure the Contractor cleans each shaft so at least 50% of the base contains less than ½ inch of sediment. The shaft bottom should have no more than 1 ½ inches of debris above the required bottom elevation. Use a weighted tape to check the bottom of the shaft excavation for debris.<br />
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Marks on the Kelly Bar should be checked to ensure the required bottom of shaft elevation. Monitor the excavation to ensure the expected amount of materials are removed by the auger, if not, caving soils are present.<br />
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Ensure the top elevation of the drilled shaft is from +1 inch to -3 inches from the top of the shaft elevation shown on the plans. For shafts outside of this tolerance range, contact the Geotechnical Services area for recommendations as to corrections. [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Subsection 718.03.C.4] of the Standard Specifications for Construction dictates contractual obligations of the contractor to correct out of tolerance shafts.<br />
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Verify the soil cuttings as they are removed from the auger, and notify the Geotechnical Services area if soil cuttings appear different than those shown on the soil borings. Ensure the Contractor stores soil cuttings away from the drill shaft locations.<br />
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===[[#Obstruction Removal|Obstruction Removal]]===<br />
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Obstructions are to be removed per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.F.2] of the Standard Specifications for Construction. Obstructions may include old concrete foundations, abandoned utilities, or boulders and cobbles. Ensure the Contractor uses tools and procedures as approved by the Geotechnical Services Section to remove the obstructions. Special procedures and tools include:<br />
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* Chisels<br />
* Boulder breakers<br />
* Core barrels<br />
* Air tools<br />
* Hand excavation<br />
* Temporary casing<br />
* Enlarging the drilled shaft diameter<br />
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Removal of obstructions that require special equipment or tools will be measured and paid for as extra work per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.04.D] of the Standard Specifications or Construction. A budget amount will be established to pay for removing obstructions. If the Contractor and the Engineer cannot agree on a lump sum price, the Engineer will direct the work to be done on a force account basis.<br />
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===[[#Placing Steel Reinforcement|Placing Steel Reinforcement]]===<br />
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Check the plans and specifications to verify the Contractor is using the correct size longitudinal bars and lateral or spiral reinforcement, and correct bar lap lengths if used.<br />
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Reinforcing cage – maintain the top of the reinforcing steel cage no greater than 1 inch above, and no greater than 3 inches below the required position. Measure the distance between the top of shaft and the top of reinforcing cage with a straight edge, and direct the Contractor to correct the position if out of tolerance.<br />
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Ensure the Contractor provides a fully assembled steel reinforcement cage for inspection at least two working days before the start of construction. Ensure all longitudinal bars and lateral or spiral reinforcement is properly tied. Ensure plastic spacers are tied at the quarter points around the cage perimeter, but no greater than 30 inches apart.<br />
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Ensure the plastic spacers are spaced at intervals no greater than 5 feet along the length of the cage for #8 bar or smaller, and 10’ for bars larger than #8 to ensure a minimum annular space of 3 inches between the outside of the cage and the side of the excavation or casing. See Figure 7 for an example of plastic spacers on the rebar cage.<br />
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[[File:Fig 718-7.png|600px|framed|center|Figure 7. Rebar cage spacers]]<br />
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Ensure the Contractor does not use concrete blocks, wood blocks, or metal chairs as spacers, as these will not retain the required spacing, and will shift out of position during cage lowering, or during the concrete pour.<br />
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The Contractor may use concrete blocks at the bottom of the shaft to maintain concrete cover over the reinforcement. Ensure the Contractor picks and lowers the reinforcement cage into the shaft in a controlled manner, as not to cause racking or distorting of the tied cage. See Figure 8 for a typical reinforcement cage being lowered into the completed shaft.<br />
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[[File:Fig 718-8.png|600px|framed|center|Figure 8. Rebar cage being lowered into complete shaft]]<br />
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Ensure the Contractor holds down the cage to control vertical displacement during concrete placement or casing extraction.<br />
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===[[#Placing Concrete|Placing Concrete]]===<br />
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Ensure the Contractor places concrete as soon as possible after the excavation and reinforcement cage placement. If too much time has elapsed, loose or soft materials may accumulate at the bottom of the shaft, thus affecting the structural integrity. If this happens, direct the Contractor to remove the reinforcement cage, and remove loose or soft materials.<br />
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Use lighting to inspect the reinforcement cage and side of excavation for dry method construction. Ensure loose materials and groundwater is removed prior to placement of concrete.<br />
<br />
Inspect by probing and measuring the shaft for wet method construction. The Contractor is required to place the concrete in one continuous operation starting from the bottom of the shaft. Once concrete reaches the top of the shaft, inspect the concrete for contaminants, and direct the Contractor to continue concrete placement until good quality concrete flows over the top of the shaft. The concrete should not be vibrated. Ensure the Contractor uses a sump or channel adjacent to the shaft to transmit displaced fluid and concrete away from the shaft opening. If polymer slurry is used, ensure the Contractor collects and disposes of the drilling fluids or polymer slurry appropriately. <br />
<br />
Track the volume of concrete going into the shafts based on tickets, and perform theoretical concrete volume calculation based on the diameter and the length of the shaft. If the numbers vary by too much, it is possible a void is present.<br />
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<br />
====[[#Free Fall Concrete Placement|Free Fall Concrete Placement]]====<br />
<br />
Free fall concrete placement can only be done in a dry shaft excavation.<br />
<br />
The falling concrete cannot strike the sides of the excavation or the reinforcing cage. Ensure the Contractor uses a centering drop chute at least 3 feet long. If concrete strikes the sides of the excavation or the reinforcing cage, direct the Contractor to reduce the height of free fall, the rate of concrete flow, or both. The free fall height limit is 80 feet.<br />
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<br />
====[[#Tremie Tube Concrete Placement|Tremie Tube Concrete Placement]]====<br />
<br />
Ensure the Contractor is using a tremie tube of at least 10 inches in diameter. Inspect the bottom of the Contractor’s tremie tube to ensure there is a bottom plate, valve, or plug so no water can get into the tube and contaminate the concrete prior to placement.<br />
<br />
The tremie tube must be placed at the bottom of the shaft, and once the plate or plug is removed, or valve is opened, ensure the Contractor keeps the discharge end 5 feet to 10 feet immersed in concrete before raising the tremie tube.<br />
<br />
It is ideal for the concrete to be placed continuously until complete, however, should the Contractor need to withdraw the tremie tube from the concrete, ensure the discharge end is re-sealed, charged with concrete, and inserted back into the concrete at least 10 feet before continuing with the concrete placement.<br />
<br />
For cased shafts, it is important discharge keep a head of concrete above the bottom of casing to be removed, and then remove the casing slowly, to allow the concrete to fill the annular space created by the case thickness. If the concrete level goes down during case extraction, direct the Contractor to stop the extraction, and add more concrete.<br />
<br />
The concrete must be placed in a timely fashion, so the slump does not go below 4”, as the concrete will not properly envelope the rebar cage, or fill the shaft to the required diameter. See Figure 9 for an example of concrete not filling the required shaft diameter.<br />
<br />
Allow the concrete to continue flowing at the top of the shaft, until quality concrete displaces all drilling fluid. Drilling fluid at the top of the shaft may have to be pumped of.<br />
<br />
Ensure the Contractor provides a hand floated surface finish at the top of the shaft concrete per [http://mdotcf.state.mi.us/public/specbook/files/2012/706%20Str%20Conc%20Construction.pdf subsection 706.06.M.2] of the Standard Specifications for Construction.<br />
<br />
* Do not remove the tremie tube from the concrete to take concrete QA samples.<br />
<br />
[[File:Fig 718-9.png|600px|framed|center|Figure 9. Improper concrete placement]]<br />
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<br />
====[[#Pumped Concrete Placement|Pumped Concrete Placement]]====<br />
<br />
Concrete can be pumped for by dry and wet shaft excavations, however, for use in wet excavations, ensure the Contractor provides a pump discharge tube with watertight joints.<br />
<br />
Pumped concrete is very similar to tremie concrete in terms of operations. The main issue to watch is the sway and movement of the pumping pipes during concrete placement. Ensure the Contractor guides or anchors the pumping pipes as to not disturb already placed fresh concrete.<br />
<br />
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<br />
===[[#POST CONSTRUCTION INTEGRITY TESTING|POST CONSTRUCTION INTEGRITY TESTING]]===<br />
<br />
Check the plans and specifications for any type of post construction integrity testing to be done on the completed shaft. There are several methods of non-destructive testing:<br />
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<br />
====[[#Pulse Echo Integrity Testing|Pulse Echo Integrity Testing]]====<br />
<br />
This type of test involves setting an ultrasonic transducer on the surfaces of the concrete, which send wave pulses through the material. Wave pulses will continue through solid concrete until a concrete to air interface, at which time the pulse is reflected back to the transducer, and a depth can be measured. In the presence of voids, the wave would reflect back sooner than expected given the overall thickness of the materials.<br />
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<br />
====[[#Cross Hole Sonic Logging|Cross Hole Sonic Logging]]====<br />
<br />
This type of test involves the attachment of steel access tubes to the vertical cage rebar prior to concrete placement. The concrete is then placed and allowed to cure. Immediately after concrete placement, the steel access tubes are to be filled with water to protect from concrete infiltration. After curing, a sound source and a received are lowered into the steel access tubes, and while keeping them at the same elevation, sonic pulses are emitted from the sound source, and the wave generated is picked up by the receiver. Based on the speed the wave propagates through the material, the receiver maps the integrity of the surrounding concrete, and voids are reported where the wave returns to the receiver at faster rates than sound areas.<br />
<br />
These types of tests are typically performed by a skilled technician, or MDOT prequalified consultant. The [http://www.michigan.gov/mdot/0,4616,7-151-9623_26663_27303-269622--,00.html Geotechnical Services Section] will be present during integrity testing to help analyze and interpret results.<br />
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<br />
====[[#Coring|Coring]]====<br />
<br />
Coring is a destructive test to remove cores of concrete from the finished shaft, and perform testing to determine concrete quality. Coring may also be done when voids are identified during non-destructive tests to reach the detected void. Grout can then be used to fill the void, and the core holes.<br />
<br />
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<br />
==[[#MEASUREMENT AND PAYMENT|MEASUREMENT AND PAYMENT]]==<br />
<br />
<span style="color: red"> -Reserved- </span><br />
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[[Category:Construction Manual]]<br />
<br />
<br />
<center><span STYLE="font: 60pt arial;">'''719'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Earth Retaining Structures'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/719%20Earth%20Retaining%Structures.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 719]</center><br />
<br />
==[[#General|General]]==<br />
<br />
Below is a list with definitions of common earth retaining structures utilized by MDOT:<br />
<br />
*Abutment – A structure located at the end of a bridge span that supports the vertical loads from the bridge superstructure, and resists lateral loads from fill material on which the roadway rests immediately adjacent to the bridge.<br />
<br />
*Anchored Wall – An earth retaining system typically composed of the same elements as non-gravity cantilevered walls and that derive additional lateral resistance from one or more tiers of anchors.<br />
<br />
*Mechanically Stabilized Earth (MSE) Wall – A soil-retaining system, employing either strip or grid-type, metallic, or polymeric tensile reinforcements in the soil mass, and a facing element that is either vertical or nearly vertical.<br />
<br />
*Segmental Block Retaining Wall – A soil-retaining system, typically employing polymeric tensile reinforcements in the soil mass attached to a facing element that consists of segmental blocks. Segmental blocks are typically dry cast blocks.<br />
<br />
*Modular Block Retaining Wall – A soil-retaining system that consists of modular blocks stacked to form a gravity wall with a vertical or nearly vertical face. Modular blocks are typically large precast concrete blocks.<br />
<br />
*Non-Gravity Cantilever Retaining Wall – A soil-retaining system that derives lateral resistance through embedment of vertical wall elements and supports retained soil with facing elements. Vertical wall elements may consist of discrete elements (piles, drilled shafts, etc.) or a continuous system (sheet piles, tangent drilled shafts, etc.).<br />
<br />
*Rigid Gravity and Semi-Gravity Retaining Wall – A structure that provides lateral support for a mass of soil and that owes its stability primarily to its own weight and to the weight of any soil located directly above its base.<br />
<br />
Some of these elements may not be detailed on the plans, and may require shop drawing submittals for approval. See 707 of the MDOT Construction Manual for shop drawing requirements.<br />
<br />
==[[#Abutments|Abutments]]==<br />
<br />
MDOT utilizes the following types of abutments:<br />
<br />
*Curtainwall Abutment (see rigid-gravity retaining wall below);<br />
<br />
<br />
[[File:Fig 719.png|600px|framed|center|Figure 1. Unreinforced concrete rigid-gravity wall, or curtain wall abutment]]<br />
<br />
<br />
<br />
*Cantilevered Abutment (see semi-gravity retaining wall below)<br />
<br />
<br />
[[File:Fig 719.png|600px|framed|center|Figure 2. reinforced cantilever abutment wall]]<br />
<br />
<br />
<br />
*Integral and Semi-Integral Abutments – Integral and semi-integral abutments are detailed in the MDOT Bridge Design Guides 6.20.04, 6.20.04B, 6.20.04D.<br />
<br />
Integral abutments are designed to be supported on a single row of piles that are oriented with their webs parallel to the bridge reference line to allow weak axis bending to accommodate superstructure articulation due to thermal gradient and live loading. Splices for piles in integral abutments must be complete joint penetration (CJP). Alternative mechanical splicer channels are not permitted.<br />
<br />
==[[#Anchored Wall|Anchored Wall]]==<br />
<br />
Anchored walls can consist of ground anchors or tie backs. Verification load testing and proof load testing of the ground anchors is typically performed on all anchors to ensure the actual lateral pullout resistance is within the design tolerances. The verification load testing procedures will be detailed in the contract documents.<br />
<br />
<br />
<br />
==[[#Mechanically Stabilized Earth Wall| Mechanically Stabilized Earth Wall]]==<br />
<br />
Below are the basic components of a mechanically stabilized earth (MSE) wall system and a summary of items to review during construction:<br />
<br />
:A.Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed. Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.<br />
<br />
:B.Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office. <br />
Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.<br />
<br />
:C. Wire Facing Panels – Wire facing panels are typically specified for temporary MSE walls during Stage I construction. The walls end up being buried into the final structure and are not removed. The wire facing panels in this temporary application are usually black steel due to the short duration of use.<br />
<br />
:D. Soil Reinforcement – MDOT permits the use of steel strip-type (bar or welded wire fabric ladder) reinforcement. Soil reinforcement must be placed as close to perpendicular from the wall face as practical. The reinforcement is permitted to be skewed around piling or other obstructions, but should be done so to not only reduce the skew, but also the number of skewed reinforcement strips. Reinforcement should not be in contact with other reinforcement. For skewed reinforcement soil must be placed between overlapping reinforcement. <br />
<br />
:E. Bolts – Bolts are typically positioned with the head at the bottom side of the connection lug and the washer and nut on the top side. This allows the inspector to visually inspect that the washers and nuts have been installed as the reinforced soil is constructed behind the wall. <br />
<br />
:F. Concrete Facing Panel Joint Material – Geotextile fabric is used to prevent soil particles from moving through the concrete facing panels. If the facing panel joints start to open up then the contractor should double the geotextile over the joints in question to provide additional protection.<br />
<br />
:G. Backfill for Reinforced Soil Mass – Granular soil, typically Granular Material Class II, whic is free draining and meets the required strength and electro-chemical properties. This material must be tested and approved prior to placement.<br />
<br />
:H. Leveling Pad – Is a non-reinforced concrete pad that provides a level starting point for constructing the precast concrete facing panels. A leveling pad is not needed for a wire faced MSE wall.<br />
<br />
:I. Impervious Membrane – A polyvinylchloride (PVC) liner that prevents chloride laden runoff from penetrating into the reinforced soil mass and corroding the steel reinforcement. The liner must be shingle-lapped or seam welded and is positioned to slope away from the front of the wall and extend a minimum distance beyond the end of the soil reinforcement.<br />
<br />
:J. CIP Copings – These copings are typically used as closure pours, but can also run up to 20 feet in length and can overlap adjacent panels without the need for a bond breaker. Expansion joint material is needed when butting CIP coping up to precast coping.<br />
<br />
:K. Foundation Underdrains – Are strategically placed to transport water from the reinforced soil mass to a location far away from the wall. MSE walls are generally not designed for hydrostatic pressure. Foundation underdrains are to be installed at the locations indicated on the plans. The lower foundation underdrains are to be located as low as possible but still drain to either a ditch or a drainage structure.<br />
<br />
MSE Wall Construction Considerations<br />
<br />
*During the wet cure for the concrete bridge deck the water coming off of the deck needs to be collected and discharged away from the MSE wall. Water runoff from the deck may saturate the MSE backfill and cause wall movement.<br />
<br />
*Groundwater needs to be controlled to prevent hydrostatic forces from acting on the wall. If groundwater is encountered during construction the location/number of foundation underdrains may need to be reevaluated.<br />
<br />
*Compaction of the Select Backfill and any subgrade undercuts is important in order to limit any future settlement of the MSE wall fill.<br />
<br />
[[File:Fig 719.png|600px|framed|center|Figure 1. MSE wall]]<br />
<br />
<br />
==[[#Non-Gravity Cantilevered Retaining Wall| Non-Gravity Cantilevered Retaining Wall]]==<br />
<br />
Examples of on-gravity cantilevered retaining walls are listed below:<br />
*Tangent piles or drilled shafts;<br />
*Drilled shafts or auger-cast piles spanned by structural facing (lagging, panels or shotcrete);<br />
*Steel sheet piling (see Section 704 – Steel Sheet Piling and Cofferdams).<br />
<br />
==[[#Rigid-Gravity and Semi-Gravity Retaining Wall|Rigid-Gravity and Semi-Gravity Retaining Wall]]==<br />
<br />
[[File:Fig 719.png|600px|framed|center|Figure 3. Reinforced concrete counterfort semi-gravity wall]]<br />
<br />
<br />
<br />
[[File:Fig 718.png|600px|framed|center|Figure 4. Reinforced concrete cantilever semi-gravity wall.]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=718_-_Drilled_Shafts&diff=3876718 - Drilled Shafts2014-11-12T18:42:59Z<p>HarrisR18: </p>
<hr />
<div><br />
<center><span STYLE="font: 60pt arial;">'''718'''</span></center><br />
<br />
<center><span STYLE="font: 40pt arial;">'''Drilled Shafts'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 718]</center><br />
<br />
<br />
==[[#GENERAL|GENERAL]]==<br />
<br />
Drilled shaft foundations are also referred to caissons, drilled piers, or bored piles, and consist of circular shafts of varying diameter, drilled to a design depth, reinforced with a steel rebar cage, and filled with concrete. Drilled shaft foundations can support large loads, and are used when driving steel piles is not feasible, or surrounding structures or utilities are too sensitive to survive the vibrations from steel foundation pile driving operations. Like steel foundation piles, loads from the superstructure transfer into the drilled shafts, which transfer loads to soil layers through side friction, end bearing, or a combination of the two. Drilled shafts are used for bridge foundations, and other ancillary structure foundations such as sign cantilevers and trusses, and signal strain poles.<br />
<br />
Drilled shafts can be constructed in the dry, or in the wet, and can also include a steel casing.<br />
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<br />
===[[#DRY CONSTRUCTION METHOD|DRY CONSTRUCTION METHOD]]===<br />
<br />
Dry construction methods are generally used when the water table is below the bottom of the shaft, and the existing soils are stiff enough as not to sloughing or caving into the hole during drilling operations. Any accumulated water greater than 3 inches at the bottom of the shaft must be pumped out prior to rebar and concrete placement, and during concrete placement, water cannot flow into the shaft at a rate greater than 12 inches within 1 hour.<br />
<br />
Typical issues with dry construction methods are if the soils are unstable, or the water table is too high, but the Contractor attempts to force dry shaft construction. In this scenario, soil caving problems will lead to soil inclusions in the shaft concrete, affecting the shaft integrity. If any problems like this arise during construction, contact the Geotechnical Services area.<br />
<br />
Another issue to watch for is if the Contractor leaves the excavation open for too long prior to reinforcement cage and concrete placement. Soils that were capable of maintaining hole stability during the drilling operations may shrink or swell over time and slowly lose that ability, resulting in caving leading to soil inclusions in the shaft concrete affecting the shaft integrity.<br />
<br />
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<br />
===[[#WET CONSTRUCTION METHOD|WET CONSTRUCTION METHOD]]===<br />
<br />
Wets construction methods are generally used where a dry excavation cannot be maintained during drilling, or shaft concrete placement. This typically occurs in areas of high water tables, and sandy soils that would otherwise slough or cave into the shaft during drilling operations. Water or a polymer slurry is used to contain water seepage, and maintain stability of the shaft excavation. Polymer slurry must be de-sanded and cleaned if used. Temporary surface casings are typically used to ensure shaft alignment. The rebar cage is lowered into the shaft, and concrete is placed using a tremie tube, or concrete pump capable of reaching the bottom of the shaft.<br />
<br />
Typical issues with wet construction methods are inexperienced Contractors that do not understand the mechanics of polymer slurry construction, and the need to ensure proper suspension of sediment and cuttings for removal, and control of caving. This can lead to shafts not being properly cleaned of sediment, resulting in voids, or inclusions in the concrete, affecting the shaft integrity.<br />
<br />
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<br />
===[[#DRY TEMPORARY CASING METHOD|DRY TEMPORARY CASING METHOD]]===<br />
<br />
Dry temporary cased construction methods are generally used where caving soils occur, over soil or rock deformations are expected, but the casing can maintain a dry and stable excavation. The casing is advanced simultaneously with the excavation. After placement of the rebar cage, the casing is then withdrawn slowly during concrete placement until removed at the top of shaft.<br />
<br />
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<br />
===[[#WET TEMPORARY CASING METHOD|WET TEMPORARY CASING METHOD]]===<br />
<br />
Wet temporary cased construction methods are generally used where caving soils occur, and a dry excavation cannot be maintained, the soils are too permeable, and the groundwater is higher than the bottom of the shaft. The casing is advanced simultaneously with the excavation, but it is important that no drilling occur outside the casing through any caving soil layers. After placement of the rebar cage, the concrete is placed using a tremie tube or concrete pump capable of reaching the bottom of the shaft. The water in the casing is not to be pumped out, rather it is to be displaced by the concrete placement.<br />
<br />
It is important to ensure the Contractor maintains a positive fluid pressure head in the shaft above the ground water elevation, or material from the side walls of the shaft will be pulled into the bottom of the shaft.<br />
<br />
For both the wet and dry casing methods, the casing is typically installed in a telescoping fashion, where the top casings may be larger than the drilled shaft diameter as called for on the plans. The depth of the hole will also dictate how many sections of casing are to be used. Ensure the contractor does not telescope the casings down to a diameter less than the design diameter as shown on the plans.<br />
<br />
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<br />
==[[#MATERIALS|MATERIALS]]==<br />
<br />
===[[#Concrete, Grade S2, and Grade T|Concrete, Grade S2, and Grade T]]===<br />
<br />
Ensure concrete materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/701%20PCC%20for%20Structures.pdf section 701] of the Standard Specifications for Construction, except modifications for the slump requirements per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.02] of the Standard Specifications for Construction. Concrete Grade S2 is to be used for dry construction, and Concrete Grade T is to be used for wet construction.<br />
<br />
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<br />
===[[#Steel Reinforcement|Steel Reinforcement]]===<br />
<br />
Ensure steel reinforcement bars are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/905%20Steel%20Reinforcement.pdf section 905] of the Standard Specifications for Construction. Check the plans and specifications for epoxy rebar requirements.<br />
<br />
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<br />
===[[#Steel Casing|Steel Casing]]===<br />
<br />
Ensure steel casing materials are in accordance with [http://mdotcf.state.mi.us/public/specbook/files/2012/919%20Perm%20Traf%20Signs,%20Supports.pdf section 919.10] of the Standard Specifications for Construction. Permanent casing will also require Buy America certification, temporary casings will not, unless left in place.<br />
<br />
Review the plans for temporary casing-left in place cut off elevations. The Contractor is required to provide casing to be smooth and watertight, and capable of withstanding the pressure of concrete and the lateral earth pressures exerted down the length of the shaft. Ensure the outside diameter of the casing is at least equal to the diameter of the shaft as called for on the plans.<br />
<br />
Temporary casings should come equipped with hook holes, or other attachments to aid in the removal as the concrete pour advances. The concrete placement is to be complete prior to complete removal of the casing. The casings should be removed slowly, and with pull forces being in line with the shaft axis. Do not allow the contractor to pull shaft casings with equipment offset from the centerline of the shaft, as this will either disrupt the already placed concrete, or case caving of soil materials into the plastic concrete.<br />
<br />
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<br />
===[[#Polymer slurry|Polymer slurry]]===<br />
<br />
When wet construction methods are required, polymer type slurry is required. Bentonite slurry is prohibited. Ensure the polymer slurry is of sufficient specific gravity to ensure stability of the excavation during drilling operations, and allows for concrete placement. The Geotechnical Services area will typically review and approve the Contractor’s proposed polymer slurry materials.<br />
<br />
Ensure any polymer slurry used meets the requirements of [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Table 718-1] from the Standard Specifications for Construction. Ensure the Contractor maintains the height of polymer slurry to prevent the side walls of the excavation from caving, and the bottom from heaving.<br />
<br />
Ensure the contractor pre-mixes the polymer slurry materials with clean, fresh water, and allow time for hydration prior to pumping into shaft excavation. The polymer slurry should be agitated to prevent setting up in the shaft.<br />
<br />
If de-sanding is required, ensure the Contractor provides the appropriate equipment. Prior to placement of shaft concrete, take polymer slurry samples with a polymer slurry test kit to determine if heavily contaminated polymer slurry at the bottom of the shaft is to be removed. Ensure the Contractor controls and collects polymer slurry exiting the excavation as the concrete displaces the volume. Review the plans for polymer slurry handling and disposal requirements.<br />
<br />
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<br />
==[[#CONSTRUCTION|CONSTRUCTION]]==<br />
<br />
===[[#EQUIPMENT|Equipment]]===<br />
<br />
Ensure the contractor is using appropriate equipment to drill the shafts given the site conditions reported in the soil borings, and geotechnical subsurface exploration report. See Figure 1 for a typical drill rig set up. The major components of drill rig include:<br />
<br />
* Crawler or truck mounted auger<br />
* Auger of the appropriate type – rock auger, single or double flight earth auger. See Figure 2 for a double flight earth auger, see Figure 3 for a single flight rock auger.<br />
* Muck or clean out bucket – see Figures 4 and 5 for a muck bucket example.<br />
* Rock core barrel – see Figure 6 for a rock core barrel example.<br />
[[File:Fig 718-1.png|600px|framed|center|Figure 1. Typical drill rig set up]]<br />
<br />
[[File:Fig 718-2.png|600px|framed|center|Figure 2. Double flight earth auger]]<br />
<br />
[[File:Fig 718-3.png|600px|framed|center|Figure 3. Single flight rock auger]]<br />
<br />
[[File:Fig 718-4.png|600px|framed|center|Figure 4. Muck bucket]]<br />
<br />
[[File:Fig 718-5.png|600px|framed|center|Figure 5. Muck bucket bottom]]<br />
<br />
[[File:Fig 718-6.png|600px|framed|center|Figure 6. Soft rock core barrel]]<br />
<br />
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<br />
===[[#DRILLED SHAFT CONSTRUCTION|DRILLED SHAFT CONSTRUCTION]]===<br />
To track drilled shaft operations, use MDOT [http://mdotcf.state.mi.us/public/webforms/public/1988.pdf form 1988] – DRILLED SHAFT INSPECTION RECORD FOR HIGHWAY SIGNS, LUMINAIRES, AND TRAFFIC SIGNALS.<br />
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<br />
====[[#Prior to Drilled Shaft Operations|Prior to Drilled Shaft Operations]]====<br />
<br />
The Contractor is required to submit a Drilled Shaft Installation plan, per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.A] of the Standard Specifications for Construction. This plan is to detail all equipment to be used, the construction sequence, rebar and concrete placement, etc. The Geotechnical Services area will review and approve the Drilled Shaft Installation plan. Review and understand the following:<br />
<br />
* Proposed equipment, including cranes, drills, augers, core barrels, bailing buckets, cleaning equipment, polymer slurry pumps and cleaning equipment, tremie tubes or concrete pumps, and casing.<br />
<br />
* Construction sequence, including methods to ensure a stable excavation, and removal of materials at the bottom of the shaft prior to rebar cage placement.<br />
<br />
* Shaft excavation methods, including proposed excavation methods through supporting and caving soil layers.<br />
<br />
* Method to mix, circulate and de-sand polymer slurry for wet construction methods.<br />
<br />
* Reinforcement placement, including support and centering methods.<br />
<br />
* Concrete placement, including free fall, tremie, or concrete pumping procedures.<br />
<br />
* Methods to prevent drilled shaft excavation spoils from entering waterways, wetlands and floodplains.<br />
<br />
* Fall protection plan conforming to MIOSHA Construction Safety Standards, including a rescue plan for shafts with a diameter of at least 30 inches, and at least 6 feet deep. This must be in place prior to commencement of any drilling operations.<br />
<br />
* Conformance with shaft diameter and rebar requirements based on details shown in the plans.<br />
<br />
Ensure the Contractor has brought all of the proposed equipment as stated in their approved Drilled Shaft Installation plan.<br />
<br />
If the shaft is to be constructed during the wet method, verify if the Contractor is allowed to use water as the drilling fluid, or if polymer slurry is required. Typically, Contractors will want to use water, but water will not prevent caving in deeper shafts. The use of bentonite slurry is prohibited.<br />
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<br />
====[[#During Drilling Operations|During Drilling Operations]]====<br />
<br />
Ensure the Contractor performs the following:<br />
<br />
* Check the drilled shaft dimensions and the alignment with reference stakes and plumb bob.<br />
<br />
* Check the dimensions and alignment of the casing inserted in the excavation.<br />
<br />
* Insert a rigid rod assembly with several 90-degree offsets equal to the shaft diameter into the shaft excavation to ensure required diameter.<br />
<br />
* Construction Method Log: The Contractor is required to submit a daily construction method log during drilled shaft excavation and construction per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.5] of the Standard Specifications for Construction. Ensure the following information is shown on the logs:<br />
<br />
* Start dates and completions dates<br />
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* Drilled shaft identification number<br />
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* Location<br />
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* Actual top and bottom elevation of drilled shaft <br />
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* Shaft diameter<br />
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* Final centerline location at top of shaft<br />
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* Variation of drilled shaft from plumb<br />
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* Top and bottom elevation of any permanent casing<br />
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* Description of each soil and rock material encountered during excavating and the top and bottom depths or elevations<br />
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* Depth drilled into bearing stratum<br />
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* Top and bottom elevations of obstructions encountered<br />
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* Amount of obstruction time<br />
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* Depth or elevation of encountered seepage of groundwater<br />
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* Actual volume of concrete placed, compared to the theoretical concrete volume to detect any large void or intrusions of extraneous materials<br />
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* Any remarks to better describe operations.<br />
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Ensure the Contractor maintains the required drilling fluid or polymer slurry levels to prevent caving.<br />
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Construction tolerances – Ensure the drilled shafts are within 3 inches horizontally of centerlines shown on the plans, and the drilled shaft is no more than 1 percent out of plumb, as measured horizontally from the actual center of the shaft at the shaft design top elevation.<br />
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Ensure the Contractor cleans each shaft so at least 50% of the base contains less than ½ inch of sediment. The shaft bottom should have no more than 1 ½ inches of debris above the required bottom elevation. Use a weighted tape to check the bottom of the shaft excavation for debris.<br />
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Marks on the Kelly Bar should be checked to ensure the required bottom of shaft elevation. Monitor the excavation to ensure the expected amount of materials are removed by the auger, if not, caving soils are present.<br />
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Ensure the top elevation of the drilled shaft is from +1 inch to -3 inches from the top of the shaft elevation shown on the plans. For shafts outside of this tolerance range, contact the Geotechnical Services area for recommendations as to corrections. [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf Subsection 718.03.C.4] of the Standard Specifications for Construction dictates contractual obligations of the contractor to correct out of tolerance shafts.<br />
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Verify the soil cuttings as they are removed from the auger, and notify the Geotechnical Services area if soil cuttings appear different than those shown on the soil borings. Ensure the Contractor stores soil cuttings away from the drill shaft locations.<br />
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===[[#Obstruction Removal|Obstruction Removal]]===<br />
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Obstructions are to be removed per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.03.F.2] of the Standard Specifications for Construction. Obstructions may include old concrete foundations, abandoned utilities, or boulders and cobbles. Ensure the Contractor uses tools and procedures as approved by the Geotechnical Services Section to remove the obstructions. Special procedures and tools include:<br />
<br />
* Chisels<br />
* Boulder breakers<br />
* Core barrels<br />
* Air tools<br />
* Hand excavation<br />
* Temporary casing<br />
* Enlarging the drilled shaft diameter<br />
<br />
Removal of obstructions that require special equipment or tools will be measured and paid for as extra work per [http://mdotcf.state.mi.us/public/specbook/files/2012/718%20Drilled%20Shafts.pdf subsection 718.04.D] of the Standard Specifications or Construction. A budget amount will be established to pay for removing obstructions. If the Contractor and the Engineer cannot agree on a lump sum price, the Engineer will direct the work to be done on a force account basis.<br />
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===[[#Placing Steel Reinforcement|Placing Steel Reinforcement]]===<br />
<br />
Check the plans and specifications to verify the Contractor is using the correct size longitudinal bars and lateral or spiral reinforcement, and correct bar lap lengths if used.<br />
<br />
Reinforcing cage – maintain the top of the reinforcing steel cage no greater than 1 inch above, and no greater than 3 inches below the required position. Measure the distance between the top of shaft and the top of reinforcing cage with a straight edge, and direct the Contractor to correct the position if out of tolerance.<br />
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Ensure the Contractor provides a fully assembled steel reinforcement cage for inspection at least two working days before the start of construction. Ensure all longitudinal bars and lateral or spiral reinforcement is properly tied. Ensure plastic spacers are tied at the quarter points around the cage perimeter, but no greater than 30 inches apart.<br />
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Ensure the plastic spacers are spaced at intervals no greater than 5 feet along the length of the cage for #8 bar or smaller, and 10’ for bars larger than #8 to ensure a minimum annular space of 3 inches between the outside of the cage and the side of the excavation or casing. See Figure 7 for an example of plastic spacers on the rebar cage.<br />
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[[File:Fig 718-7.png|600px|framed|center|Figure 7. Rebar cage spacers]]<br />
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Ensure the Contractor does not use concrete blocks, wood blocks, or metal chairs as spacers, as these will not retain the required spacing, and will shift out of position during cage lowering, or during the concrete pour.<br />
<br />
The Contractor may use concrete blocks at the bottom of the shaft to maintain concrete cover over the reinforcement. Ensure the Contractor picks and lowers the reinforcement cage into the shaft in a controlled manner, as not to cause racking or distorting of the tied cage. See Figure 8 for a typical reinforcement cage being lowered into the completed shaft.<br />
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[[File:Fig 718-8.png|600px|framed|center|Figure 8. Rebar cage being lowered into complete shaft]]<br />
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Ensure the Contractor holds down the cage to control vertical displacement during concrete placement or casing extraction.<br />
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===[[#Placing Concrete|Placing Concrete]]===<br />
<br />
Ensure the Contractor places concrete as soon as possible after the excavation and reinforcement cage placement. If too much time has elapsed, loose or soft materials may accumulate at the bottom of the shaft, thus affecting the structural integrity. If this happens, direct the Contractor to remove the reinforcement cage, and remove loose or soft materials.<br />
<br />
Use lighting to inspect the reinforcement cage and side of excavation for dry method construction. Ensure loose materials and groundwater is removed prior to placement of concrete.<br />
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Inspect by probing and measuring the shaft for wet method construction. The Contractor is required to place the concrete in one continuous operation starting from the bottom of the shaft. Once concrete reaches the top of the shaft, inspect the concrete for contaminants, and direct the Contractor to continue concrete placement until good quality concrete flows over the top of the shaft. The concrete should not be vibrated. Ensure the Contractor uses a sump or channel adjacent to the shaft to transmit displaced fluid and concrete away from the shaft opening. If polymer slurry is used, ensure the Contractor collects and disposes of the drilling fluids or polymer slurry appropriately. <br />
<br />
Track the volume of concrete going into the shafts based on tickets, and perform theoretical concrete volume calculation based on the diameter and the length of the shaft. If the numbers vary by too much, it is possible a void is present.<br />
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====[[#Free Fall Concrete Placement|Free Fall Concrete Placement]]====<br />
<br />
Free fall concrete placement can only be done in a dry shaft excavation.<br />
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The falling concrete cannot strike the sides of the excavation or the reinforcing cage. Ensure the Contractor uses a centering drop chute at least 3 feet long. If concrete strikes the sides of the excavation or the reinforcing cage, direct the Contractor to reduce the height of free fall, the rate of concrete flow, or both. The free fall height limit is 80 feet.<br />
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====[[#Tremie Tube Concrete Placement|Tremie Tube Concrete Placement]]====<br />
<br />
Ensure the Contractor is using a tremie tube of at least 10 inches in diameter. Inspect the bottom of the Contractor’s tremie tube to ensure there is a bottom plate, valve, or plug so no water can get into the tube and contaminate the concrete prior to placement.<br />
<br />
The tremie tube must be placed at the bottom of the shaft, and once the plate or plug is removed, or valve is opened, ensure the Contractor keeps the discharge end 5 feet to 10 feet immersed in concrete before raising the tremie tube.<br />
<br />
It is ideal for the concrete to be placed continuously until complete, however, should the Contractor need to withdraw the tremie tube from the concrete, ensure the discharge end is re-sealed, charged with concrete, and inserted back into the concrete at least 10 feet before continuing with the concrete placement.<br />
<br />
For cased shafts, it is important discharge keep a head of concrete above the bottom of casing to be removed, and then remove the casing slowly, to allow the concrete to fill the annular space created by the case thickness. If the concrete level goes down during case extraction, direct the Contractor to stop the extraction, and add more concrete.<br />
<br />
The concrete must be placed in a timely fashion, so the slump does not go below 4”, as the concrete will not properly envelope the rebar cage, or fill the shaft to the required diameter. See Figure 9 for an example of concrete not filling the required shaft diameter.<br />
<br />
Allow the concrete to continue flowing at the top of the shaft, until quality concrete displaces all drilling fluid. Drilling fluid at the top of the shaft may have to be pumped of.<br />
<br />
Ensure the Contractor provides a hand floated surface finish at the top of the shaft concrete per [http://mdotcf.state.mi.us/public/specbook/files/2012/706%20Str%20Conc%20Construction.pdf subsection 706.06.M.2] of the Standard Specifications for Construction.<br />
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* Do not remove the tremie tube from the concrete to take concrete QA samples.<br />
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[[File:Fig 718-9.png|600px|framed|center|Figure 9. Improper concrete placement]]<br />
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====[[#Pumped Concrete Placement|Pumped Concrete Placement]]====<br />
<br />
Concrete can be pumped for by dry and wet shaft excavations, however, for use in wet excavations, ensure the Contractor provides a pump discharge tube with watertight joints.<br />
<br />
Pumped concrete is very similar to tremie concrete in terms of operations. The main issue to watch is the sway and movement of the pumping pipes during concrete placement. Ensure the Contractor guides or anchors the pumping pipes as to not disturb already placed fresh concrete.<br />
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===[[#POST CONSTRUCTION INTEGRITY TESTING|POST CONSTRUCTION INTEGRITY TESTING]]===<br />
<br />
Check the plans and specifications for any type of post construction integrity testing to be done on the completed shaft. There are several methods of non-destructive testing:<br />
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====[[#Pulse Echo Integrity Testing|Pulse Echo Integrity Testing]]====<br />
<br />
This type of test involves setting an ultrasonic transducer on the surfaces of the concrete, which send wave pulses through the material. Wave pulses will continue through solid concrete until a concrete to air interface, at which time the pulse is reflected back to the transducer, and a depth can be measured. In the presence of voids, the wave would reflect back sooner than expected given the overall thickness of the materials.<br />
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====[[#Cross Hole Sonic Logging|Cross Hole Sonic Logging]]====<br />
<br />
This type of test involves the attachment of steel access tubes to the vertical cage rebar prior to concrete placement. The concrete is then placed and allowed to cure. Immediately after concrete placement, the steel access tubes are to be filled with water to protect from concrete infiltration. After curing, a sound source and a received are lowered into the steel access tubes, and while keeping them at the same elevation, sonic pulses are emitted from the sound source, and the wave generated is picked up by the receiver. Based on the speed the wave propagates through the material, the receiver maps the integrity of the surrounding concrete, and voids are reported where the wave returns to the receiver at faster rates than sound areas.<br />
<br />
These types of tests are typically performed by a skilled technician, or MDOT prequalified consultant. The [http://www.michigan.gov/mdot/0,4616,7-151-9623_26663_27303-269622--,00.html Geotechnical Services Section] will be present during integrity testing to help analyze and interpret results.<br />
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====[[#Coring|Coring]]====<br />
<br />
Coring is a destructive test to remove cores of concrete from the finished shaft, and perform testing to determine concrete quality. Coring may also be done when voids are identified during non-destructive tests to reach the detected void. Grout can then be used to fill the void, and the core holes.<br />
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==[[#MEASUREMENT AND PAYMENT|MEASUREMENT AND PAYMENT]]==<br />
<br />
<span style="color: red"> -Reserved- </span><br />
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[[Category:Construction Manual]]<br />
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<br />
<center><span STYLE="font: 60pt arial;">'''719'''</span></center><br />
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<center><span STYLE="font: 40pt arial;">'''Earth Retaining Structures'''</span></center><br />
<br />
<center>[http://mdotcf.state.mi.us/public/specbook/files/2012/719%20Earth%20Retaining%Structures.pdf 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 719]</center><br />
<br />
==[[#General|General]]==<br />
<br />
Below is a list with definitions of common earth retaining structures utilized by MDOT:<br />
<br />
*Abutment – A structure located at the end of a bridge span that supports the vertical loads from the bridge superstructure, and resists lateral loads from fill material on which the roadway rests immediately adjacent to the bridge.<br />
<br />
*Anchored Wall – An earth retaining system typically composed of the same elements as non-gravity cantilevered walls and that derive additional lateral resistance from one or more tiers of anchors.<br />
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*Mechanically Stabilized Earth (MSE) Wall – A soil-retaining system, employing either strip or grid-type, metallic, or polymeric tensile reinforcements in the soil mass, and a facing element that is either vertical or nearly vertical.<br />
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*Segmental Block Retaining Wall – A soil-retaining system, typically employing polymeric tensile reinforcements in the soil mass attached to a facing element that consists of segmental blocks. Segmental blocks are typically dry cast blocks.<br />
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*Modular Block Retaining Wall – A soil-retaining system that consists of modular blocks stacked to form a gravity wall with a vertical or nearly vertical face. Modular blocks are typically large precast concrete blocks.<br />
<br />
*Non-Gravity Cantilever Retaining Wall – A soil-retaining system that derives lateral resistance through embedment of vertical wall elements and supports retained soil with facing elements. Vertical wall elements may consist of discrete elements (piles, drilled shafts, etc.) or a continuous system (sheet piles, tangent drilled shafts, etc.).<br />
<br />
*Rigid Gravity and Semi-Gravity Retaining Wall – A structure that provides lateral support for a mass of soil and that owes its stability primarily to its own weight and to the weight of any soil located directly above its base.<br />
<br />
Some of these elements may not be detailed on the plans, and may require shop drawing submittals for approval. See 707 of the MDOT Construction Manual for shop drawing requirements.<br />
<br />
==[[#Abutments|Abutments]]==<br />
<br />
MDOT utilizes the following types of abutments:<br />
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*Curtainwall Abutment (see rigid-gravity retaining wall below);<br />
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<br />
*Cantilevered Abutment (see semi-gravity retaining wall below)<br />
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*Integral and Semi-Integral Abutments – Integral and semi-integral abutments are detailed in the MDOT Bridge Design Guides 6.20.04, 6.20.04B, 6.20.04D.<br />
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Integral abutments are designed to be supported on a single row of piles that are oriented with their webs parallel to the bridge reference line to allow weak axis bending to accommodate superstructure articulation due to thermal gradient and live loading. Splices for piles in integral abutments must be complete joint penetration (CJP). Alternative mechanical splicer channels are not permitted.<br />
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==[[#Anchored Wall|Anchored Wall]]==<br />
<br />
Anchored walls can consist of ground anchors or tie backs. Verification load testing and proof load testing of the ground anchors is typically performed on all anchors to ensure the actual lateral pullout resistance is within the design tolerances. The verification load testing procedures will be detailed in the contract documents.<br />
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<br />
==[[#Mechanically Stabilized Earth Wall| Mechanically Stabilized Earth Wall]]==<br />
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Below are the basic components of a mechanically stabilized earth (MSE) wall system and a summary of items to review during construction:<br />
<br />
:A.Subgrade Preparation – The Region Soils Engineer must be contacted to inspect the reinforced soil mass area plus 3 feet after the subgrade is prepared and before the wall is constructed. Subgrade undercutting may be required, depending on the recommendations from the Region Soils Engineer, and quantities in the contract documents.<br />
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:B.Precast Concrete Facing Panels, Corners and Copings – The Structural Fabrication Unit will coordinate with the project office to determine if these panels will be shop inspected. If they are shop inspected then each panel will have the MDOT approved for use stamp on them and they will be completely inspected (including material certifications and Buy America) by the Structural Fabrication Unit. If they are not shop inspected then verification of project requirements is the responsibility of the project office. <br />
Field inspectors must perform a visual inspection on the elements as soon as they are unloaded to check for signs of shipping or handling damage. The panels must also be properly stored on-site to prevent damage.<br />
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:C. Wire Facing Panels – Wire facing panels are typically specified for temporary MSE walls during Stage I construction. The walls end up being buried into the final structure and are not removed. The wire facing panels in this temporary application are usually black steel due to the short duration of use.<br />
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:D. Soil Reinforcement – MDOT permits the use of steel strip-type (bar or welded wire fabric ladder) reinforcement. Soil reinforcement must be placed as close to perpendicular from the wall face as practical. The reinforcement is permitted to be skewed around piling or other obstructions, but should be done so to not only reduce the skew, but also the number of skewed reinforcement strips. Reinforcement should not be in contact with other reinforcement. For skewed reinforcement soil must be placed between overlapping reinforcement. <br />
<br />
:E. Bolts – Bolts are typically positioned with the head at the bottom side of the connection lug and the washer and nut on the top side. This allows the inspector to visually inspect that the washers and nuts have been installed as the reinforced soil is constructed behind the wall. <br />
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:F. Concrete Facing Panel Joint Material – Geotextile fabric is used to prevent soil particles from moving through the concrete facing panels. If the facing panel joints start to open up then the contractor should double the geotextile over the joints in question to provide additional protection.<br />
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:G. Backfill for Reinforced Soil Mass – Granular soil, typically Granular Material Class II, whic is free draining and meets the required strength and electro-chemical properties. This material must be tested and approved prior to placement.<br />
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:H. Leveling Pad – Is a non-reinforced concrete pad that provides a level starting point for constructing the precast concrete facing panels. A leveling pad is not needed for a wire faced MSE wall.<br />
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:I. Impervious Membrane – A polyvinylchloride (PVC) liner that prevents chloride laden runoff from penetrating into the reinforced soil mass and corroding the steel reinforcement. The liner must be shingle-lapped or seam welded and is positioned to slope away from the front of the wall and extend a minimum distance beyond the end of the soil reinforcement.<br />
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:J. CIP Copings – These copings are typically used as closure pours, but can also run up to 20 feet in length and can overlap adjacent panels without the need for a bond breaker. Expansion joint material is needed when butting CIP coping up to precast coping.<br />
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:K. Foundation Underdrains – Are strategically placed to transport water from the reinforced soil mass to a location far away from the wall. MSE walls are generally not designed for hydrostatic pressure. Foundation underdrains are to be installed at the locations indicated on the plans. The lower foundation underdrains are to be located as low as possible but still drain to either a ditch or a drainage structure.<br />
<br />
MSE Wall Construction Considerations<br />
<br />
*During the wet cure for the concrete bridge deck the water coming off of the deck needs to be collected and discharged away from the MSE wall. Water runoff from the deck may saturate the MSE backfill and cause wall movement.<br />
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*Groundwater needs to be controlled to prevent hydrostatic forces from acting on the wall. If groundwater is encountered during construction the location/number of foundation underdrains may need to be reevaluated.<br />
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*Compaction of the Select Backfill and any subgrade undercuts is important in order to limit any future settlement of the MSE wall fill.<br />
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==[[#Non-Gravity Cantilevered Retaining Wall| Non-Gravity Cantilevered Retaining Wall]]==</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=Disadvantaged_Business_Enterprises_(DBE)&diff=3866Disadvantaged Business Enterprises (DBE)2014-11-10T19:52:01Z<p>HarrisR18: </p>
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<div>===[[#Equal Employment Opportunity|Equal Employment Opportunity]]===<br />
<br />
MDOT must ensure that all federal-aid contractors, sub-contractors, vendors, and material suppliers do not discriminate in employment and contracting practices based on race, color, religion (in the context of employment), sex, national origin, age, or disability.<br />
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Any deficiencies noted in a contractor’s EEO program are to be provided to the [mailto:MDOT-DBE@michigan.gov MDOT Office of Business Development (OBD)] at 866-323-1264.<br />
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A contractor’s affirmative action plan is to be comprised of the following contractual requirements: EO provisions, training provisions, Federal Highway Administration (FHWA) Form 1273, Title VI (under Appendix C of the project proposal) and Disadvantaged Business Enterprise (DBE) goals and provisions.<br />
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===[[#Title VI Coordinator|Title VI Coordinator]]=== <br />
<br />
Cheryl Hudson is MDOT’s Title VI Coordinator. She can be contacted at 517-373-0980 or at [mailto:HudsonC1@michigan.gov Cheryl Hudson] for any issues related to civil rights.<br />
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===[[#Title VI Definition|Title VI Definition]]===<br />
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No person in the United States shall, on the grounds of race, color, or national origin, be excluded from participation in, be denied the benefits of, or be otherwise subjected to discrimination under any program or activity funded in whole or in part with federal funds.<br />
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===[[#Equal Opprotunity (EO) Contract Compliance|Equal Opprotunity (EO) Contract Compliance]]===<br />
<br />
MDOT’s OBD conducts federally-required EO and EEO compliance reviews as part of its monitoring responsibilities. OBD staff determines whether the contractor took all necessary and reasonable steps to comply with these requirements.<br />
<br />
EO requirements in FHWA, Form 1273, Required Contract Provisions Federal-Aid Construction Contracts, apply to all contractors, subcontractors, vendors and suppliers on all federal-aid contracts of $10,000 or more. As specified in FHWA Form 1273, the contractor (or subcontractor) must include this form in each subcontract and further require its inclusion in all lower tier subcontracts (excluding purchase orders, rental agreements and other agreements for supplies or services).<br />
<br />
FHWA Form 1273 is to be physically incorporated in each federal-aid highway construction contract and subcontract. Form 1273 may be bound electronically into an electronic contract/subcontract (PDF format) but may not be left out and only referenced (website location, etc.) as it must be physically included in every contract/subcontract. The construction/project engineer should discuss FHWA Form 1273 at the preconstruction meeting.<br />
<br />
The construction/project engineer must ensure that contractors EO posters are in order and conspicuously placed on the project site as the FHWA requires contractors to prominently display posters in areas available to employees and applicants for employment during the life of the project. The poster display is to include the prime contractor’s EEO policy statement and the name and contact information of the prime’s EEO Officer. All notices and posters are to be legible, protected from the elements, and the dates must be shown. Mobile operations can have the posters located in a vehicle. Complete [http://mdotcf.state.mi.us/public/webforms/public/1967.pdf Form 1967], Jobsite Poster Inspection Checklist, at the start of construction operations and any time the poster display is moved. The form is an aid to make sure that the contractor is following the proper procedure and is to be placed in the project files after completion of the form.<br />
<br />
Job site posters should be discussed at the preconstruction meeting. The required job site posting information can be found under Section C at the following MDOT website: http://www.michigan.gov/mdot/0,4616,7-151-9622_11044_11367-222170--,00.html. <br />
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If construction staff receives a complaint from the employee of a contractor or subcontractor they are to notify through email [mailto:DBE@michigan.gov OBD] or call at 866-323-1264 (all MDOT Regions except Metro) or 866-323-4009 (Metro Region).<br />
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If construction staff receives a complaint involving an MDOT employee or other persons who are not employees of contractors on a project, they are to contact the MDOT Title VI Coordinator.<br />
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Construction staff is to evaluate any problems or issues encountered with EEO, DBE or Title VI compliance when completing contractor performance evaluations.<br />
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===[[#On-The-Job Training|On-The-Job Training]]===<br />
<br />
MDOT’s OJT program is based on requirements of Appendix B to Subpart A of Title 23 Code of Federal Regulations Part 230 (23 CFR Part 230), which requires inclusion of training special provisions in federal-aid construction contracts. The OJT program provides opportunities for unskilled workers to acquire training in skilled construction trades. The primary objective of the OJT program is to train and upgrade minorities, women, and disadvantaged persons toward full journey-level status and to provide opportunities for trainees to become part of a contractor’s permanent workforce. OJT program details are available from MDOT’s OBD or on the web at http://michigan.gov/ojt.<br />
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===[[#Disadvantages Business Enterprises (DBE)|Disadvantages Business Enterprises (DBE)]]===<br />
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DBE companies are contractors (prime, sub, sub-sub, etc.), truckers, materials suppliers, consultants and other service providers who are certified as having met requirements of 49 CFR Part 26. A current list of all DBE companies certified to work in Michigan by work classification and work type is available at: http://www.michigan.gov/mucp<br />
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The document titled, 2013 DBE Program Procedures, is MDOT’s federally-approved plan for its DBE program. This document contains detailed information and is available at http://www.michigan.gov/mdotdbe under the Resources link.<br />
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DBE race-conscious (RC) participation goals are expressed as a percentage of work which must be contracted to DBE companies for applicable projects with a DBE goal. On RC projects the prime contractor is required to provide DBE commitment sheets ([http://mdotcf.state.mi.us/public/webforms/public/0178.pdf Form 0178], Disadvantaged Business Enterprise (DBE) Participation) prior to contract award. The construction/project engineer is notified via email (or file presence in ProjectWise) of the prime contractor DBE commitments on RC projects or when there are changes in the goal or DBE companies committed to the project. These notifications are to be provided to construction staff assigned to the project. DBE commitments, subcontracts, and the current DBE goal (when applicable) assigned to a project are posted on MDOT’s Construction Contract Inquiry website at http://mdotcf.state.mi.us/public/trnsport/.<br />
<br />
The following tasks related to DBE oversight are to be completed on all federally funded projects. The task list provides guidance to project construction staff related to their responsibilities for oversight of DBE compliance.<br />
<br />
1.Collect all DBE subcontracts and purchase orders from prime contractor. Provide copies of purchase orders to OBD with the respective [http://mdotcf.state.mi.us/public/webforms/public/4109.pdf 4109 form] submittal.<br />
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2.Review DBE commitment sheets ([http://mdotcf.state.mi.us/public/webforms/public/0178.pdf form 0178], also known as blue sheets) for awareness and knowledge.<br />
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3.Monitor and document DBE work operations.<br />
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4.Monitor and document Commercially Useful Function (CUF) compliance ([http://mdotcf.state.mi.us/public/webforms/public/4109.pdf form 4109]) during construction operations and provide a copy of [http://mdotcf.state.mi.us/public/webforms/public/4109.pdf form 4109] to OBD as noted on the form.<br />
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5.Monitor compliance with DBE commitments (work type, amounts committed, DBE payments, etc.).<br />
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6.Monitor overall DBE participation percentage as construction work progresses.<br />
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7.Calculate the final overall DBE participation percentage to check for compliance with the contract requirements. Contact OBD with non-compliance issues.<br />
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8.Document all DBE contracting issues, concerns, problems, etc. and provide to OBD for discussion and resolution.<br />
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9.Provide all DBE substitution forms in accordance with form instructions and distribution lists.<br />
<br />
When the construction/project engineer becomes aware that a DBE goal will not be met due to the inability of a DBE to perform work, changes in DBE subcontracting, reduced quantities, changes in the work, etc., the construction/project engineer must direct the contractor to submit a specific plan to address the goal deficiency to the engineer. The construction/project engineer will provide a copy of the submitted plan to OBD.<br />
<br />
The contractor may, after award, request a waiver or modification of the DBE participation goal. The contractor must submit evidence of good faith efforts to meet the DBE participation goal. This includes documentation to support that the amount of contract work remaining was carefully reviewed to identify other work which could be subcontracted to DBE firms.<br />
<br />
If the prime contractor is not meeting its RC DBE participation goal after project award, it must request a post award waiver or modification of the goal. These requests are to be submitted with [http://mdotcf.state.mi.us/public/webforms/public/0188.pdf Form 0188], Contractor Good Faith Effort Application. Requests for waiver or modification of a DBE participation goal must be submitted to OBD immediately upon awareness.<br />
<br />
Contractors are not allowed to arbitrarily reduce the amount of work committed to DBE companies or terminate a DBE subcontractor without construction/project engineer approval, including the self performance of previously committed DBE work. The construction/project engineer is to be notified of a DBE company’s inability to perform work and the contractor’s intent to obtain a substitute DBE on projects with race-conscious (RC) DBE participation goals. A DBE who is unable to perform work must be given five business days written notice by the contractor of their intent to obtain a substitute DBE. The contractor is required to provide copies of the notice to the construction/project engineer and OBD. To substitute DBE companies, the prime contractor must then submit Form 0196, Request to Replace Disadvantaged Business Enterprise. The construction/project engineer must review and approve (in consultation with OBD) any DBE substitutions before submitting the approved form to the MDOT Contract Services Division.<br />
<br />
Work items, if applicable and available, must be properly assigned in FieldManager to the respective DBE company. Construction staff must document work done by all DBE companies, including truckers, suppliers, service providers, and subcontractors. Documentation is to occur on the Inspector Daily Reports (IDR) or the Commercially Useful Function [http://mdotcf.state.mi.us/public/webforms/public/4109.pdf Form 4109] submittal and should include any concerns or problems. All potential field concerns are to be discussed with OBD staff.<br />
<br />
{{top}}<br />
<br />
===[[#DBE Construction Engineers and Technicians|DBE Construction Engineers and Technicians]]===<br />
<br />
MDOT has assigned construction engineers and technicians by region to help DBE companies bidding or working on construction contracts. The DBE Technician list is available at: http://www.michigan.gov/mdotdbe under the contacts heading.<br />
<br />
{{top}}<br />
===[[#Third Party Complaints|Third Party Complaints]]===<br />
<br />
Any person may file a written complaint alleging that a currently certified firm is in violation of DBE regulations. Complaints must be filed with OBD in writing no later than 180 days after the date of an alleged violation. For further information, refer to the DBE Program Procedures as discussed previously.<br />
<br />
{{top}}<br />
===[[#DBE Commercially Useful Function (CUF) Requirements|DBE Commercially Useful Function (CUF) Requirements]]===<br />
<br />
Field direction on this issue can be reviewed with Bureau of Highway Instructional Memorandum, 2013-12, Disadvantaged Business Enterprise (DBE) Commercially Useful Function (CUF) Compliance or any applicable superseding BOHIM.<br />
<br />
{{top}}<br />
<br />
===[[#Joint Checks|Joint Checks]]===<br />
<br />
A joint check is a two party check between a subcontractor, a prime contractor, and a materials supplier. Joint check arrangements must be approved by OBD and the Contract Services Division in advance of use. MDOT Form 0183, Application to Use Joint Checks, is included in project proposals and must be submitted to the OBD for approval at least two weeks in advance of use of any joint checks.<br />
<br />
{{top}}<br />
<br />
===[[#DBE Documentation| DBE Documentation]]===<br />
<br />
The construction/project engineer should compare names of DBE companies and payments listed via submittal of form 2124A with the following items to check for discrepancies or compliance issues:<br />
<br />
*DBE companies listed on MDOT [http://mdotcf.state.mi.us/public/webforms/public/0178.pdf Form 0178], Disadvantaged Business Enterprise (DBE) Participation.<br />
*The types of work listed on [http://mdotcf.state.mi.us/public/webforms/public/0178.pdf forms 0178] or [http://mdotcf.state.mi.us/public/webforms/public/0182.pdf 0182] with the services/work classification listed on [http://mdotcf.state.mi.us/public/webforms/public/2124A.pdf form 2124A].<br />
*Project scheduling and anticipated work presence by DBE companies.<br />
*Any reports of non-compliance with prompt payment requirements.<br />
<br />
Construction/Project engineers should question any deductions shown on [http://mdotcf.state.mi.us/public/webforms/public/2124A.pdf form 2124A]. Contractors are not permitted to hold any type of retainage per MDOT policy. Holding of retainage or making partial payment to subcontractors for work that was approved and paid by MDOT is to be reported to the Construction Field Services Division.<br />
<br />
{{top}}<br />
<br />
===[[#Questions|Questions]]===<br />
<br />
OBD can be contacted at [MAILTO:MDOT-DBE@michigan.gov MDOT-DBE@michigan.gov] with any DBE related questions or concerns. Messages can be left at 866-323-1264 or 866-323-4009 and an OBD staff person will respond.<br />
<br />
Please share this information with consultants and local agencies in your area. If you have any questions, please contact Jason Gutting, Engineer of Construction Operations, at [mailto:guttingj@michigan.gov Jason Gutting] or 517-636-6334.<br />
<br />
{{top}}<br />
<br />
[[Category: Construction Manual]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=Disadvantaged_Business_Enterprises_(DBE)&diff=3865Disadvantaged Business Enterprises (DBE)2014-11-10T19:49:07Z<p>HarrisR18: </p>
<hr />
<div>===[[#Equal Employment Opportunity|Equal Employment Opportunity]]===<br />
<br />
MDOT must ensure that all federal-aid contractors, sub-contractors, vendors, and material suppliers do not discriminate in employment and contracting practices based on race, color, religion (in the context of employment), sex, national origin, age, or disability.<br />
<br />
Any deficiencies noted in a contractor’s EEO program are to be provided to the [mailto:MDOT-DBE@michigan.gov MDOT Office of Business Development (OBD)] at 866-323-1264.<br />
<br />
A contractor’s affirmative action plan is to be comprised of the following contractual requirements: EO provisions, training provisions, Federal Highway Administration (FHWA) Form 1273, Title VI (under Appendix C of the project proposal) and Disadvantaged Business Enterprise (DBE) goals and provisions.<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Coordinator|Title VI Coordinator]]=== <br />
<br />
Cheryl Hudson is MDOT’s Title VI Coordinator. She can be contacted at 517-373-0980 or at [mailto:HudsonC1@michigan.gov Cheryl Hudson] for any issues related to civil rights.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Definition|Title VI Definition]]===<br />
<br />
No person in the United States shall, on the grounds of race, color, or national origin, be excluded from participation in, be denied the benefits of, or be otherwise subjected to discrimination under any program or activity funded in whole or in part with federal funds.<br />
<br />
{{top}}<br />
<br />
===[[#Equal Opprotunity (EO) Contract Compliance|Equal Opprotunity (EO) Contract Compliance]]===<br />
<br />
MDOT’s OBD conducts federally-required EO and EEO compliance reviews as part of its monitoring responsibilities. OBD staff determines whether the contractor took all necessary and reasonable steps to comply with these requirements.<br />
<br />
EO requirements in FHWA, Form 1273, Required Contract Provisions Federal-Aid Construction Contracts, apply to all contractors, subcontractors, vendors and suppliers on all federal-aid contracts of $10,000 or more. As specified in FHWA Form 1273, the contractor (or subcontractor) must include this form in each subcontract and further require its inclusion in all lower tier subcontracts (excluding purchase orders, rental agreements and other agreements for supplies or services).<br />
<br />
FHWA Form 1273 is to be physically incorporated in each federal-aid highway construction contract and subcontract. Form 1273 may be bound electronically into an electronic contract/subcontract (PDF format) but may not be left out and only referenced (website location, etc.) as it must be physically included in every contract/subcontract. The construction/project engineer should discuss FHWA Form 1273 at the preconstruction meeting.<br />
<br />
The construction/project engineer must ensure that contractors EO posters are in order and conspicuously placed on the project site as the FHWA requires contractors to prominently display posters in areas available to employees and applicants for employment during the life of the project. The poster display is to include the prime contractor’s EEO policy statement and the name and contact information of the prime’s EEO Officer. All notices and posters are to be legible, protected from the elements, and the dates must be shown. Mobile operations can have the posters located in a vehicle. Complete [http://mdotcf.state.mi.us/public/webforms/public/1967.pdf Form 1967], Jobsite Poster Inspection Checklist, at the start of construction operations and any time the poster display is moved. The form is an aid to make sure that the contractor is following the proper procedure and is to be placed in the project files after completion of the form.<br />
<br />
Job site posters should be discussed at the preconstruction meeting. The required job site posting information can be found under Section C at the following MDOT website: http://www.michigan.gov/mdot/0,4616,7-151-9622_11044_11367-222170--,00.html. <br />
<br />
<br />
If construction staff receives a complaint from the employee of a contractor or subcontractor they are to notify through email [mailto:DBE@michigan.gov OBD] or call at 866-323-1264 (all MDOT Regions except Metro) or 866-323-4009 (Metro Region).<br />
<br />
If construction staff receives a complaint involving an MDOT employee or other persons who are not employees of contractors on a project, they are to contact the MDOT Title VI Coordinator.<br />
<br />
Construction staff is to evaluate any problems or issues encountered with EEO, DBE or Title VI compliance when completing contractor performance evaluations.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#On-The-Job Training|On-The-Job Training]]===<br />
<br />
MDOT’s OJT program is based on requirements of Appendix B to Subpart A of Title 23 Code of Federal Regulations Part 230 (23 CFR Part 230), which requires inclusion of training special provisions in federal-aid construction contracts. The OJT program provides opportunities for unskilled workers to acquire training in skilled construction trades. The primary objective of the OJT program is to train and upgrade minorities, women, and disadvantaged persons toward full journey-level status and to provide opportunities for trainees to become part of a contractor’s permanent workforce. OJT program details are available from MDOT’s OBD or on the web at http://michigan.gov/ojt.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#Disadvantages Business Enterprises (DBE)|Disadvantages Business Enterprises (DBE)]]===<br />
<br />
DBE companies are contractors (prime, sub, sub-sub, etc.), truckers, materials suppliers, consultants and other service providers who are certified as having met requirements of 49 CFR Part 26. A current list of all DBE companies certified to work in Michigan by work classification and work type is available at: http://www.michigan.gov/mucp<br />
<br />
The document titled, 2013 DBE Program Procedures, is MDOT’s federally-approved plan for its DBE program. This document contains detailed information and is available at http://www.michigan.gov/mdotdbe under the Resources link.<br />
<br />
DBE race-conscious (RC) participation goals are expressed as a percentage of work which must be contracted to DBE companies for applicable projects with a DBE goal. On RC projects the prime contractor is required to provide DBE commitment sheets ([http://mdotcf.state.mi.us/public/webforms/public/0178.pdf Form 0178], Disadvantaged Business Enterprise (DBE) Participation) prior to contract award. The construction/project engineer is notified via email (or file presence in ProjectWise) of the prime contractor DBE commitments on RC projects or when there are changes in the goal or DBE companies committed to the project. These notifications are to be provided to construction staff assigned to the project. DBE commitments, subcontracts, and the current DBE goal (when applicable) assigned to a project are posted on MDOT’s Construction Contract Inquiry website at http://mdotcf.state.mi.us/public/trnsport/.<br />
<br />
The following tasks related to DBE oversight are to be completed on all federally funded projects. The task list provides guidance to project construction staff related to their responsibilities for oversight of DBE compliance.<br />
<br />
1.Collect all DBE subcontracts and purchase orders from prime contractor. Provide copies of purchase orders to OBD with the respective [http://mdotcf.state.mi.us/public/webforms/public/4109.pdf 4109 form] submittal.<br />
<br />
2.Review DBE commitment sheets ([http://mdotcf.state.mi.us/public/webforms/public/0178.pdf form 0178], also known as blue sheets) for awareness and knowledge.<br />
<br />
3.Monitor and document DBE work operations.<br />
<br />
4.Monitor and document Commercially Useful Function (CUF) compliance ([http://mdotcf.state.mi.us/public/webforms/public/4109.pdf form 4109]) during construction operations and provide a copy of [http://mdotcf.state.mi.us/public/webforms/public/4109.pdf form 4109] to OBD as noted on the form.<br />
<br />
5.Monitor compliance with DBE commitments (work type, amounts committed, DBE payments, etc.).<br />
<br />
6.Monitor overall DBE participation percentage as construction work progresses.<br />
<br />
7.Calculate the final overall DBE participation percentage to check for compliance with the contract requirements. Contact OBD with non-compliance issues.<br />
<br />
8.Document all DBE contracting issues, concerns, problems, etc. and provide to OBD for discussion and resolution.<br />
<br />
9.Provide all DBE substitution forms in accordance with form instructions and distribution lists.<br />
<br />
When the construction/project engineer becomes aware that a DBE goal will not be met due to the inability of a DBE to perform work, changes in DBE subcontracting, reduced quantities, changes in the work, etc., the construction/project engineer must direct the contractor to submit a specific plan to address the goal deficiency to the engineer. The construction/project engineer will provide a copy of the submitted plan to OBD.<br />
<br />
The contractor may, after award, request a waiver or modification of the DBE participation goal. The contractor must submit evidence of good faith efforts to meet the DBE participation goal. This includes documentation to support that the amount of contract work remaining was carefully reviewed to identify other work which could be subcontracted to DBE firms.<br />
<br />
If the prime contractor is not meeting its RC DBE participation goal after project award, it must request a post award waiver or modification of the goal. These requests are to be submitted with [http://mdotcf.state.mi.us/public/webforms/public/0188.pdf Form 0188], Contractor Good Faith Effort Application. Requests for waiver or modification of a DBE participation goal must be submitted to OBD immediately upon awareness.<br />
<br />
Contractors are not allowed to arbitrarily reduce the amount of work committed to DBE companies or terminate a DBE subcontractor without construction/project engineer approval, including the self performance of previously committed DBE work. The construction/project engineer is to be notified of a DBE company’s inability to perform work and the contractor’s intent to obtain a substitute DBE on projects with race-conscious (RC) DBE participation goals. A DBE who is unable to perform work must be given five business days written notice by the contractor of their intent to obtain a substitute DBE. The contractor is required to provide copies of the notice to the construction/project engineer and OBD. To substitute DBE companies, the prime contractor must then submit Form 0196, Request to Replace Disadvantaged Business Enterprise. The construction/project engineer must review and approve (in consultation with OBD) any DBE substitutions before submitting the approved form to the MDOT Contract Services Division.<br />
<br />
Work items, if applicable and available, must be properly assigned in FieldManager to the respective DBE company. Construction staff must document work done by all DBE companies, including truckers, suppliers, service providers, and subcontractors. Documentation is to occur on the Inspector Daily Reports (IDR) or the Commercially Useful Function [http://mdotcf.state.mi.us/public/webforms/public/4109.pdf Form 4109] submittal and should include any concerns or problems. All potential field concerns are to be discussed with OBD staff.<br />
<br />
{{top}}<br />
<br />
===[[#DBE Construction Engineers and Technicians|DBE Construction Engineers and Technicians]]===<br />
<br />
MDOT has assigned construction engineers and technicians by region to help DBE companies bidding or working on construction contracts. The DBE Technician list is available at: http://www.michigan.gov/mdotdbe under the contacts heading.<br />
<br />
{{top}}<br />
===[[#Third Party Complaints|Third Party Complaints]]===<br />
<br />
Any person may file a written complaint alleging that a currently certified firm is in violation of DBE regulations. Complaints must be filed with OBD in writing no later than 180 days after the date of an alleged violation. For further information, refer to the DBE Program Procedures as discussed previously.<br />
<br />
{{top}}<br />
===[[#DBE Commercially Useful Function (CUF) Requirements|DBE Commercially Useful Function (CUF) Requirements]]===<br />
<br />
Field direction on this issue can be reviewed with Bureau of Highway Instructional Memorandum, 2013-12, Disadvantaged Business Enterprise (DBE) Commercially Useful Function (CUF) Compliance or any applicable superseding BOHIM.<br />
<br />
{{top}}<br />
<br />
===[[#Joint Checks|Joint Checks]]===<br />
<br />
A joint check is a two party check between a subcontractor, a prime contractor, and a materials supplier. Joint check arrangements must be approved by OBD and the Contract Services Division in advance of use. MDOT Form 0183, Application to Use Joint Checks, is included in project proposals and must be submitted to the OBD for approval at least two weeks in advance of use of any joint checks.<br />
<br />
{{top}}<br />
<br />
===[[#DBE Documentation| DBE Documentation]]===<br />
<br />
The construction/project engineer should compare names of DBE companies and payments listed via submittal of form 2124A with the following items to check for discrepancies or compliance issues:<br />
<br />
*DBE companies listed on MDOT [http://mdotcf.state.mi.us/public/webforms/public/0178.pdf Form 0178], Disadvantaged Business Enterprise (DBE) Participation.<br />
*The types of work listed on [http://mdotcf.state.mi.us/public/webforms/public/0178.pdf forms 0178] or [http://mdotcf.state.mi.us/public/webforms/public/0182.pdf 0182] with the services/work classification listed on [http://mdotcf.state.mi.us/public/webforms/public/2124A.pdf form 2124A].<br />
*Project scheduling and anticipated work presence by DBE companies.<br />
*Any reports of non-compliance with prompt payment requirements.<br />
<br />
Construction/Project engineers should question any deductions shown on [http://mdotcf.state.mi.us/public/webforms/public/2124A.pdf form 2124A]. Contractors are not permitted to hold any type of retainage per MDOT policy. Holding of retainage or making partial payment to subcontractors for work that was approved and paid by MDOT is to be reported to the Construction Field Services Division.<br />
<br />
{{top}}<br />
<br />
===[[#Questions|Questions]]===<br />
<br />
OBD can be contacted at MDOT-DBE@michigan.gov with any DBE related questions or concerns. Messages can be left at 866-323-1264 or 866-323-4009 and an OBD staff person will respond.<br />
<br />
Please share this information with consultants and local agencies in your area. If you have any questions, please contact Jason Gutting, Engineer of Construction Operations, at [mailto:guttingj@michigan.gov Jason Gutting] or 517-636-6334.<br />
<br />
{{top}}<br />
<br />
[[Category: Construction Manual]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=Disadvantaged_Business_Enterprises_(DBE)&diff=3864Disadvantaged Business Enterprises (DBE)2014-11-10T19:48:05Z<p>HarrisR18: /* DBE Documentation */</p>
<hr />
<div>===[[#Equal Employment Opportunity|Equal Employment Opportunity]]===<br />
<br />
MDOT must ensure that all federal-aid contractors, sub-contractors, vendors, and material suppliers do not discriminate in employment and contracting practices based on race, color, religion (in the context of employment), sex, national origin, age, or disability.<br />
<br />
Any deficiencies noted in a contractor’s EEO program are to be provided to the [mailto:MDOT-DBE@michigan.gov MDOT Office of Business Development (OBD)] at 866-323-1264.<br />
<br />
A contractor’s affirmative action plan is to be comprised of the following contractual requirements: EO provisions, training provisions, Federal Highway Administration (FHWA) Form 1273, Title VI (under Appendix C of the project proposal) and Disadvantaged Business Enterprise (DBE) goals and provisions.<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Coordinator|Title VI Coordinator]]=== <br />
<br />
Cheryl Hudson is MDOT’s Title VI Coordinator. She can be contacted at 517-373-0980 or at [mailto:HudsonC1@michigan.gov Cheryl Hudson] for any issues related to civil rights.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Definition|Title VI Definition]]===<br />
<br />
No person in the United States shall, on the grounds of race, color, or national origin, be excluded from participation in, be denied the benefits of, or be otherwise subjected to discrimination under any program or activity funded in whole or in part with federal funds.<br />
<br />
{{top}}<br />
<br />
===[[#Equal Opprotunity (EO) Contract Compliance|Equal Opprotunity (EO) Contract Compliance]]===<br />
<br />
MDOT’s OBD conducts federally-required EO and EEO compliance reviews as part of its monitoring responsibilities. OBD staff determines whether the contractor took all necessary and reasonable steps to comply with these requirements.<br />
<br />
EO requirements in FHWA, Form 1273, Required Contract Provisions Federal-Aid Construction Contracts, apply to all contractors, subcontractors, vendors and suppliers on all federal-aid contracts of $10,000 or more. As specified in FHWA Form 1273, the contractor (or subcontractor) must include this form in each subcontract and further require its inclusion in all lower tier subcontracts (excluding purchase orders, rental agreements and other agreements for supplies or services).<br />
<br />
FHWA Form 1273 is to be physically incorporated in each federal-aid highway construction contract and subcontract. Form 1273 may be bound electronically into an electronic contract/subcontract (PDF format) but may not be left out and only referenced (website location, etc.) as it must be physically included in every contract/subcontract. The construction/project engineer should discuss FHWA Form 1273 at the preconstruction meeting.<br />
<br />
The construction/project engineer must ensure that contractors EO posters are in order and conspicuously placed on the project site as the FHWA requires contractors to prominently display posters in areas available to employees and applicants for employment during the life of the project. The poster display is to include the prime contractor’s EEO policy statement and the name and contact information of the prime’s EEO Officer. All notices and posters are to be legible, protected from the elements, and the dates must be shown. Mobile operations can have the posters located in a vehicle. Complete [http://mdotcf.state.mi.us/public/webforms/public/1967.pdf Form 1967], Jobsite Poster Inspection Checklist, at the start of construction operations and any time the poster display is moved. The form is an aid to make sure that the contractor is following the proper procedure and is to be placed in the project files after completion of the form.<br />
<br />
Job site posters should be discussed at the preconstruction meeting. The required job site posting information can be found under Section C at the following MDOT website: http://www.michigan.gov/mdot/0,4616,7-151-9622_11044_11367-222170--,00.html. <br />
<br />
<br />
If construction staff receives a complaint from the employee of a contractor or subcontractor they are to notify through email [mailto:DBE@michigan.gov OBD] or call at 866-323-1264 (all MDOT Regions except Metro) or 866-323-4009 (Metro Region).<br />
<br />
If construction staff receives a complaint involving an MDOT employee or other persons who are not employees of contractors on a project, they are to contact the MDOT Title VI Coordinator.<br />
<br />
Construction staff is to evaluate any problems or issues encountered with EEO, DBE or Title VI compliance when completing contractor performance evaluations.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#On-The-Job Training|On-The-Job Training]]===<br />
<br />
MDOT’s OJT program is based on requirements of Appendix B to Subpart A of Title 23 Code of Federal Regulations Part 230 (23 CFR Part 230), which requires inclusion of training special provisions in federal-aid construction contracts. The OJT program provides opportunities for unskilled workers to acquire training in skilled construction trades. The primary objective of the OJT program is to train and upgrade minorities, women, and disadvantaged persons toward full journey-level status and to provide opportunities for trainees to become part of a contractor’s permanent workforce. OJT program details are available from MDOT’s OBD or on the web at http://michigan.gov/ojt.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#Disadvantages Business Enterprises (DBE)|Disadvantages Business Enterprises (DBE)]]===<br />
<br />
DBE companies are contractors (prime, sub, sub-sub, etc.), truckers, materials suppliers, consultants and other service providers who are certified as having met requirements of 49 CFR Part 26. A current list of all DBE companies certified to work in Michigan by work classification and work type is available at: http://www.michigan.gov/mucp<br />
<br />
The document titled, 2013 DBE Program Procedures, is MDOT’s federally-approved plan for its DBE program. This document contains detailed information and is available at http://www.michigan.gov/mdotdbe under the Resources link.<br />
<br />
DBE race-conscious (RC) participation goals are expressed as a percentage of work which must be contracted to DBE companies for applicable projects with a DBE goal. On RC projects the prime contractor is required to provide DBE commitment sheets ([http://mdotcf.state.mi.us/public/webforms/public/0178.pdf Form 0178], Disadvantaged Business Enterprise (DBE) Participation) prior to contract award. The construction/project engineer is notified via email (or file presence in ProjectWise) of the prime contractor DBE commitments on RC projects or when there are changes in the goal or DBE companies committed to the project. These notifications are to be provided to construction staff assigned to the project. DBE commitments, subcontracts, and the current DBE goal (when applicable) assigned to a project are posted on MDOT’s Construction Contract Inquiry website at http://mdotcf.state.mi.us/public/trnsport/.<br />
<br />
The following tasks related to DBE oversight are to be completed on all federally funded projects. The task list provides guidance to project construction staff related to their responsibilities for oversight of DBE compliance.<br />
<br />
1.Collect all DBE subcontracts and purchase orders from prime contractor. Provide copies of purchase orders to OBD with the respective [http://mdotcf.state.mi.us/public/webforms/public/4109.pdf 4109 form] submittal.<br />
<br />
2.Review DBE commitment sheets ([http://mdotcf.state.mi.us/public/webforms/public/0178.pdf form 0178], also known as blue sheets) for awareness and knowledge.<br />
<br />
3.Monitor and document DBE work operations.<br />
<br />
4.Monitor and document Commercially Useful Function (CUF) compliance ([http://mdotcf.state.mi.us/public/webforms/public/4109.pdf form 4109]) during construction operations and provide a copy of [http://mdotcf.state.mi.us/public/webforms/public/4109.pdf form 4109] to OBD as noted on the form.<br />
<br />
5.Monitor compliance with DBE commitments (work type, amounts committed, DBE payments, etc.).<br />
<br />
6.Monitor overall DBE participation percentage as construction work progresses.<br />
<br />
7.Calculate the final overall DBE participation percentage to check for compliance with the contract requirements. Contact OBD with non-compliance issues.<br />
<br />
8.Document all DBE contracting issues, concerns, problems, etc. and provide to OBD for discussion and resolution.<br />
<br />
9.Provide all DBE substitution forms in accordance with form instructions and distribution lists.<br />
<br />
When the construction/project engineer becomes aware that a DBE goal will not be met due to the inability of a DBE to perform work, changes in DBE subcontracting, reduced quantities, changes in the work, etc., the construction/project engineer must direct the contractor to submit a specific plan to address the goal deficiency to the engineer. The construction/project engineer will provide a copy of the submitted plan to OBD.<br />
<br />
The contractor may, after award, request a waiver or modification of the DBE participation goal. The contractor must submit evidence of good faith efforts to meet the DBE participation goal. This includes documentation to support that the amount of contract work remaining was carefully reviewed to identify other work which could be subcontracted to DBE firms.<br />
<br />
If the prime contractor is not meeting its RC DBE participation goal after project award, it must request a post award waiver or modification of the goal. These requests are to be submitted with [http://mdotcf.state.mi.us/public/webforms/public/0188.pdf Form 0188], Contractor Good Faith Effort Application. Requests for waiver or modification of a DBE participation goal must be submitted to OBD immediately upon awareness.<br />
<br />
Contractors are not allowed to arbitrarily reduce the amount of work committed to DBE companies or terminate a DBE subcontractor without construction/project engineer approval, including the self performance of previously committed DBE work. The construction/project engineer is to be notified of a DBE company’s inability to perform work and the contractor’s intent to obtain a substitute DBE on projects with race-conscious (RC) DBE participation goals. A DBE who is unable to perform work must be given five business days written notice by the contractor of their intent to obtain a substitute DBE. The contractor is required to provide copies of the notice to the construction/project engineer and OBD. To substitute DBE companies, the prime contractor must then submit Form 0196, Request to Replace Disadvantaged Business Enterprise. The construction/project engineer must review and approve (in consultation with OBD) any DBE substitutions before submitting the approved form to the MDOT Contract Services Division.<br />
<br />
Work items, if applicable and available, must be properly assigned in FieldManager to the respective DBE company. Construction staff must document work done by all DBE companies, including truckers, suppliers, service providers, and subcontractors. Documentation is to occur on the Inspector Daily Reports (IDR) or the Commercially Useful Function [http://mdotcf.state.mi.us/public/webforms/public/4109.pdf Form 4109] submittal and should include any concerns or problems. All potential field concerns are to be discussed with OBD staff.<br />
<br />
{{top}}<br />
<br />
===[[#DBE Construction Engineers and Technicians|DBE Construction Engineers and Technicians]]===<br />
<br />
MDOT has assigned construction engineers and technicians by region to help DBE companies bidding or working on construction contracts. The DBE Technician list is available at: http://www.michigan.gov/mdotdbe under the contacts heading.<br />
<br />
{{top}}<br />
===[[#Third Party Complaints|Third Party Complaints]]===<br />
<br />
Any person may file a written complaint alleging that a currently certified firm is in violation of DBE regulations. Complaints must be filed with OBD in writing no later than 180 days after the date of an alleged violation. For further information, refer to the DBE Program Procedures as discussed previously.<br />
<br />
{{top}}<br />
===[[#DBE Commercially Useful Function (CUF) Requirements|DBE Commercially Useful Function (CUF) Requirements]]===<br />
<br />
Field direction on this issue can be reviewed with Bureau of Highway Instructional Memorandum, 2013-12, Disadvantaged Business Enterprise (DBE) Commercially Useful Function (CUF) Compliance or any applicable superseding BOHIM.<br />
<br />
{{top}}<br />
<br />
===[[#Joint Checks|Joint Checks]]===<br />
<br />
A joint check is a two party check between a subcontractor, a prime contractor, and a materials supplier. Joint check arrangements must be approved by OBD and the Contract Services Division in advance of use. MDOT Form 0183, Application to Use Joint Checks, is included in project proposals and must be submitted to the OBD for approval at least two weeks in advance of use of any joint checks.<br />
<br />
{{top}}<br />
<br />
===[[#DBE Documentation| DBE Documentation]]===<br />
<br />
The construction/project engineer should compare names of DBE companies and payments listed via submittal of form 2124A with the following items to check for discrepancies or compliance issues:<br />
<br />
*DBE companies listed on MDOT [http://mdotcf.state.mi.us/public/webforms/public/0178.pdf Form 0178], Disadvantaged Business Enterprise (DBE) Participation.<br />
*The types of work listed on [http://mdotcf.state.mi.us/public/webforms/public/0178.pdf forms 0178] or [http://mdotcf.state.mi.us/public/webforms/public/0182.pdf 0182] with the services/work classification listed on [http://mdotcf.state.mi.us/public/webforms/public/2124A.pdf form 2124A].<br />
*Project scheduling and anticipated work presence by DBE companies.<br />
*Any reports of non-compliance with prompt payment requirements.<br />
<br />
Construction/Project engineers should question any deductions shown on [http://mdotcf.state.mi.us/public/webforms/public/2124A.pdf form 2124A]. Contractors are not permitted to hold any type of retainage per MDOT policy. Holding of retainage or making partial payment to subcontractors for work that was approved and paid by MDOT is to be reported to the Construction Field Services Division.<br />
<br />
{{top}}<br />
<br />
===[[#Questions|Questions]]===<br />
<br />
OBD can be contacted at MDOT-DBE@michigan.gov with any DBE related questions or concerns. Messages can be left at 866-323-1264 or 866-323-4009 and an OBD staff person will respond.<br />
<br />
Please share this information with consultants and local agencies in your area. If you have any questions, please contact Jason Gutting, Engineer of Construction Operations, at [mailto:guttingj@michigan.gov Jason Gutting] or 517-636-6334.<br />
<br />
{{top}}<br />
<br />
===[[#Construction Manual| Construction Manual]]===<br />
<br />
The contents of this BOHIM will be placed and maintained in the MDOT Construction Manual. After incorporation the BOHIM will sunset and link directly to the Construction Manual.<br />
<br />
{{top}}<br />
<br />
[[Category: Construction Manual]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=Disadvantaged_Business_Enterprises_(DBE)&diff=3863Disadvantaged Business Enterprises (DBE)2014-11-10T19:47:32Z<p>HarrisR18: /* DBE Documentation */</p>
<hr />
<div>===[[#Equal Employment Opportunity|Equal Employment Opportunity]]===<br />
<br />
MDOT must ensure that all federal-aid contractors, sub-contractors, vendors, and material suppliers do not discriminate in employment and contracting practices based on race, color, religion (in the context of employment), sex, national origin, age, or disability.<br />
<br />
Any deficiencies noted in a contractor’s EEO program are to be provided to the [mailto:MDOT-DBE@michigan.gov MDOT Office of Business Development (OBD)] at 866-323-1264.<br />
<br />
A contractor’s affirmative action plan is to be comprised of the following contractual requirements: EO provisions, training provisions, Federal Highway Administration (FHWA) Form 1273, Title VI (under Appendix C of the project proposal) and Disadvantaged Business Enterprise (DBE) goals and provisions.<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Coordinator|Title VI Coordinator]]=== <br />
<br />
Cheryl Hudson is MDOT’s Title VI Coordinator. She can be contacted at 517-373-0980 or at [mailto:HudsonC1@michigan.gov Cheryl Hudson] for any issues related to civil rights.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Definition|Title VI Definition]]===<br />
<br />
No person in the United States shall, on the grounds of race, color, or national origin, be excluded from participation in, be denied the benefits of, or be otherwise subjected to discrimination under any program or activity funded in whole or in part with federal funds.<br />
<br />
{{top}}<br />
<br />
===[[#Equal Opprotunity (EO) Contract Compliance|Equal Opprotunity (EO) Contract Compliance]]===<br />
<br />
MDOT’s OBD conducts federally-required EO and EEO compliance reviews as part of its monitoring responsibilities. OBD staff determines whether the contractor took all necessary and reasonable steps to comply with these requirements.<br />
<br />
EO requirements in FHWA, Form 1273, Required Contract Provisions Federal-Aid Construction Contracts, apply to all contractors, subcontractors, vendors and suppliers on all federal-aid contracts of $10,000 or more. As specified in FHWA Form 1273, the contractor (or subcontractor) must include this form in each subcontract and further require its inclusion in all lower tier subcontracts (excluding purchase orders, rental agreements and other agreements for supplies or services).<br />
<br />
FHWA Form 1273 is to be physically incorporated in each federal-aid highway construction contract and subcontract. Form 1273 may be bound electronically into an electronic contract/subcontract (PDF format) but may not be left out and only referenced (website location, etc.) as it must be physically included in every contract/subcontract. The construction/project engineer should discuss FHWA Form 1273 at the preconstruction meeting.<br />
<br />
The construction/project engineer must ensure that contractors EO posters are in order and conspicuously placed on the project site as the FHWA requires contractors to prominently display posters in areas available to employees and applicants for employment during the life of the project. The poster display is to include the prime contractor’s EEO policy statement and the name and contact information of the prime’s EEO Officer. All notices and posters are to be legible, protected from the elements, and the dates must be shown. Mobile operations can have the posters located in a vehicle. Complete [http://mdotcf.state.mi.us/public/webforms/public/1967.pdf Form 1967], Jobsite Poster Inspection Checklist, at the start of construction operations and any time the poster display is moved. The form is an aid to make sure that the contractor is following the proper procedure and is to be placed in the project files after completion of the form.<br />
<br />
Job site posters should be discussed at the preconstruction meeting. The required job site posting information can be found under Section C at the following MDOT website: http://www.michigan.gov/mdot/0,4616,7-151-9622_11044_11367-222170--,00.html. <br />
<br />
<br />
If construction staff receives a complaint from the employee of a contractor or subcontractor they are to notify through email [mailto:DBE@michigan.gov OBD] or call at 866-323-1264 (all MDOT Regions except Metro) or 866-323-4009 (Metro Region).<br />
<br />
If construction staff receives a complaint involving an MDOT employee or other persons who are not employees of contractors on a project, they are to contact the MDOT Title VI Coordinator.<br />
<br />
Construction staff is to evaluate any problems or issues encountered with EEO, DBE or Title VI compliance when completing contractor performance evaluations.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#On-The-Job Training|On-The-Job Training]]===<br />
<br />
MDOT’s OJT program is based on requirements of Appendix B to Subpart A of Title 23 Code of Federal Regulations Part 230 (23 CFR Part 230), which requires inclusion of training special provisions in federal-aid construction contracts. The OJT program provides opportunities for unskilled workers to acquire training in skilled construction trades. The primary objective of the OJT program is to train and upgrade minorities, women, and disadvantaged persons toward full journey-level status and to provide opportunities for trainees to become part of a contractor’s permanent workforce. OJT program details are available from MDOT’s OBD or on the web at http://michigan.gov/ojt.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#Disadvantages Business Enterprises (DBE)|Disadvantages Business Enterprises (DBE)]]===<br />
<br />
DBE companies are contractors (prime, sub, sub-sub, etc.), truckers, materials suppliers, consultants and other service providers who are certified as having met requirements of 49 CFR Part 26. A current list of all DBE companies certified to work in Michigan by work classification and work type is available at: http://www.michigan.gov/mucp<br />
<br />
The document titled, 2013 DBE Program Procedures, is MDOT’s federally-approved plan for its DBE program. This document contains detailed information and is available at http://www.michigan.gov/mdotdbe under the Resources link.<br />
<br />
DBE race-conscious (RC) participation goals are expressed as a percentage of work which must be contracted to DBE companies for applicable projects with a DBE goal. On RC projects the prime contractor is required to provide DBE commitment sheets ([http://mdotcf.state.mi.us/public/webforms/public/0178.pdf Form 0178], Disadvantaged Business Enterprise (DBE) Participation) prior to contract award. The construction/project engineer is notified via email (or file presence in ProjectWise) of the prime contractor DBE commitments on RC projects or when there are changes in the goal or DBE companies committed to the project. These notifications are to be provided to construction staff assigned to the project. DBE commitments, subcontracts, and the current DBE goal (when applicable) assigned to a project are posted on MDOT’s Construction Contract Inquiry website at http://mdotcf.state.mi.us/public/trnsport/.<br />
<br />
The following tasks related to DBE oversight are to be completed on all federally funded projects. The task list provides guidance to project construction staff related to their responsibilities for oversight of DBE compliance.<br />
<br />
1.Collect all DBE subcontracts and purchase orders from prime contractor. Provide copies of purchase orders to OBD with the respective [http://mdotcf.state.mi.us/public/webforms/public/4109.pdf 4109 form] submittal.<br />
<br />
2.Review DBE commitment sheets ([http://mdotcf.state.mi.us/public/webforms/public/0178.pdf form 0178], also known as blue sheets) for awareness and knowledge.<br />
<br />
3.Monitor and document DBE work operations.<br />
<br />
4.Monitor and document Commercially Useful Function (CUF) compliance ([http://mdotcf.state.mi.us/public/webforms/public/4109.pdf form 4109]) during construction operations and provide a copy of [http://mdotcf.state.mi.us/public/webforms/public/4109.pdf form 4109] to OBD as noted on the form.<br />
<br />
5.Monitor compliance with DBE commitments (work type, amounts committed, DBE payments, etc.).<br />
<br />
6.Monitor overall DBE participation percentage as construction work progresses.<br />
<br />
7.Calculate the final overall DBE participation percentage to check for compliance with the contract requirements. Contact OBD with non-compliance issues.<br />
<br />
8.Document all DBE contracting issues, concerns, problems, etc. and provide to OBD for discussion and resolution.<br />
<br />
9.Provide all DBE substitution forms in accordance with form instructions and distribution lists.<br />
<br />
When the construction/project engineer becomes aware that a DBE goal will not be met due to the inability of a DBE to perform work, changes in DBE subcontracting, reduced quantities, changes in the work, etc., the construction/project engineer must direct the contractor to submit a specific plan to address the goal deficiency to the engineer. The construction/project engineer will provide a copy of the submitted plan to OBD.<br />
<br />
The contractor may, after award, request a waiver or modification of the DBE participation goal. The contractor must submit evidence of good faith efforts to meet the DBE participation goal. This includes documentation to support that the amount of contract work remaining was carefully reviewed to identify other work which could be subcontracted to DBE firms.<br />
<br />
If the prime contractor is not meeting its RC DBE participation goal after project award, it must request a post award waiver or modification of the goal. These requests are to be submitted with [http://mdotcf.state.mi.us/public/webforms/public/0188.pdf Form 0188], Contractor Good Faith Effort Application. Requests for waiver or modification of a DBE participation goal must be submitted to OBD immediately upon awareness.<br />
<br />
Contractors are not allowed to arbitrarily reduce the amount of work committed to DBE companies or terminate a DBE subcontractor without construction/project engineer approval, including the self performance of previously committed DBE work. The construction/project engineer is to be notified of a DBE company’s inability to perform work and the contractor’s intent to obtain a substitute DBE on projects with race-conscious (RC) DBE participation goals. A DBE who is unable to perform work must be given five business days written notice by the contractor of their intent to obtain a substitute DBE. The contractor is required to provide copies of the notice to the construction/project engineer and OBD. To substitute DBE companies, the prime contractor must then submit Form 0196, Request to Replace Disadvantaged Business Enterprise. The construction/project engineer must review and approve (in consultation with OBD) any DBE substitutions before submitting the approved form to the MDOT Contract Services Division.<br />
<br />
Work items, if applicable and available, must be properly assigned in FieldManager to the respective DBE company. Construction staff must document work done by all DBE companies, including truckers, suppliers, service providers, and subcontractors. Documentation is to occur on the Inspector Daily Reports (IDR) or the Commercially Useful Function [http://mdotcf.state.mi.us/public/webforms/public/4109.pdf Form 4109] submittal and should include any concerns or problems. All potential field concerns are to be discussed with OBD staff.<br />
<br />
{{top}}<br />
<br />
===[[#DBE Construction Engineers and Technicians|DBE Construction Engineers and Technicians]]===<br />
<br />
MDOT has assigned construction engineers and technicians by region to help DBE companies bidding or working on construction contracts. The DBE Technician list is available at: http://www.michigan.gov/mdotdbe under the contacts heading.<br />
<br />
{{top}}<br />
===[[#Third Party Complaints|Third Party Complaints]]===<br />
<br />
Any person may file a written complaint alleging that a currently certified firm is in violation of DBE regulations. Complaints must be filed with OBD in writing no later than 180 days after the date of an alleged violation. For further information, refer to the DBE Program Procedures as discussed previously.<br />
<br />
{{top}}<br />
===[[#DBE Commercially Useful Function (CUF) Requirements|DBE Commercially Useful Function (CUF) Requirements]]===<br />
<br />
Field direction on this issue can be reviewed with Bureau of Highway Instructional Memorandum, 2013-12, Disadvantaged Business Enterprise (DBE) Commercially Useful Function (CUF) Compliance or any applicable superseding BOHIM.<br />
<br />
{{top}}<br />
<br />
===[[#Joint Checks|Joint Checks]]===<br />
<br />
A joint check is a two party check between a subcontractor, a prime contractor, and a materials supplier. Joint check arrangements must be approved by OBD and the Contract Services Division in advance of use. MDOT Form 0183, Application to Use Joint Checks, is included in project proposals and must be submitted to the OBD for approval at least two weeks in advance of use of any joint checks.<br />
<br />
{{top}}<br />
<br />
===[[#DBE Documentation| DBE Documentation]]===<br />
<br />
The construction/project engineer should compare names of DBE companies and payments listed via submittal of form 2124A with the following items to check for discrepancies or compliance issues:<br />
<br />
*DBE companies listed on MDOT [http://mdotcf.state.mi.us/public/webforms/public/0178.pdf Form 0178], Disadvantaged Business Enterprise (DBE) Participation.<br />
*The types of work listed on [http://mdotcf.state.mi.us/public/webforms/public/0178.pdf forms 0178] or [http://mdotcf.state.mi.us/public/webforms/public/0182.pdf 0182] with the services/work classification listed on [http://mdotcf.state.mi.us/public/webforms/public/2124A.pdf form 2124A].<br />
*Project scheduling and anticipated work presence by DBE companies.<br />
*Any reports of non-compliance with prompt payment requirements.<br />
<br />
Construction/Project engineers should question any deductions shown on form 2124A. Contractors are not permitted to hold any type of retainage per MDOT policy. Holding of retainage or making partial payment to subcontractors for work that was approved and paid by MDOT is to be reported to the Construction Field Services Division.<br />
<br />
{{top}}<br />
<br />
===[[#Questions|Questions]]===<br />
<br />
OBD can be contacted at MDOT-DBE@michigan.gov with any DBE related questions or concerns. Messages can be left at 866-323-1264 or 866-323-4009 and an OBD staff person will respond.<br />
<br />
Please share this information with consultants and local agencies in your area. If you have any questions, please contact Jason Gutting, Engineer of Construction Operations, at [mailto:guttingj@michigan.gov Jason Gutting] or 517-636-6334.<br />
<br />
{{top}}<br />
<br />
===[[#Construction Manual| Construction Manual]]===<br />
<br />
The contents of this BOHIM will be placed and maintained in the MDOT Construction Manual. After incorporation the BOHIM will sunset and link directly to the Construction Manual.<br />
<br />
{{top}}<br />
<br />
[[Category: Construction Manual]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=Disadvantaged_Business_Enterprises_(DBE)&diff=3862Disadvantaged Business Enterprises (DBE)2014-11-10T19:41:39Z<p>HarrisR18: /* Disadvantages Business Enterprises (DBE) */</p>
<hr />
<div>===[[#Equal Employment Opportunity|Equal Employment Opportunity]]===<br />
<br />
MDOT must ensure that all federal-aid contractors, sub-contractors, vendors, and material suppliers do not discriminate in employment and contracting practices based on race, color, religion (in the context of employment), sex, national origin, age, or disability.<br />
<br />
Any deficiencies noted in a contractor’s EEO program are to be provided to the [mailto:MDOT-DBE@michigan.gov MDOT Office of Business Development (OBD)] at 866-323-1264.<br />
<br />
A contractor’s affirmative action plan is to be comprised of the following contractual requirements: EO provisions, training provisions, Federal Highway Administration (FHWA) Form 1273, Title VI (under Appendix C of the project proposal) and Disadvantaged Business Enterprise (DBE) goals and provisions.<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Coordinator|Title VI Coordinator]]=== <br />
<br />
Cheryl Hudson is MDOT’s Title VI Coordinator. She can be contacted at 517-373-0980 or at [mailto:HudsonC1@michigan.gov Cheryl Hudson] for any issues related to civil rights.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Definition|Title VI Definition]]===<br />
<br />
No person in the United States shall, on the grounds of race, color, or national origin, be excluded from participation in, be denied the benefits of, or be otherwise subjected to discrimination under any program or activity funded in whole or in part with federal funds.<br />
<br />
{{top}}<br />
<br />
===[[#Equal Opprotunity (EO) Contract Compliance|Equal Opprotunity (EO) Contract Compliance]]===<br />
<br />
MDOT’s OBD conducts federally-required EO and EEO compliance reviews as part of its monitoring responsibilities. OBD staff determines whether the contractor took all necessary and reasonable steps to comply with these requirements.<br />
<br />
EO requirements in FHWA, Form 1273, Required Contract Provisions Federal-Aid Construction Contracts, apply to all contractors, subcontractors, vendors and suppliers on all federal-aid contracts of $10,000 or more. As specified in FHWA Form 1273, the contractor (or subcontractor) must include this form in each subcontract and further require its inclusion in all lower tier subcontracts (excluding purchase orders, rental agreements and other agreements for supplies or services).<br />
<br />
FHWA Form 1273 is to be physically incorporated in each federal-aid highway construction contract and subcontract. Form 1273 may be bound electronically into an electronic contract/subcontract (PDF format) but may not be left out and only referenced (website location, etc.) as it must be physically included in every contract/subcontract. The construction/project engineer should discuss FHWA Form 1273 at the preconstruction meeting.<br />
<br />
The construction/project engineer must ensure that contractors EO posters are in order and conspicuously placed on the project site as the FHWA requires contractors to prominently display posters in areas available to employees and applicants for employment during the life of the project. The poster display is to include the prime contractor’s EEO policy statement and the name and contact information of the prime’s EEO Officer. All notices and posters are to be legible, protected from the elements, and the dates must be shown. Mobile operations can have the posters located in a vehicle. Complete [http://mdotcf.state.mi.us/public/webforms/public/1967.pdf Form 1967], Jobsite Poster Inspection Checklist, at the start of construction operations and any time the poster display is moved. The form is an aid to make sure that the contractor is following the proper procedure and is to be placed in the project files after completion of the form.<br />
<br />
Job site posters should be discussed at the preconstruction meeting. The required job site posting information can be found under Section C at the following MDOT website: http://www.michigan.gov/mdot/0,4616,7-151-9622_11044_11367-222170--,00.html. <br />
<br />
<br />
If construction staff receives a complaint from the employee of a contractor or subcontractor they are to notify through email [mailto:DBE@michigan.gov OBD] or call at 866-323-1264 (all MDOT Regions except Metro) or 866-323-4009 (Metro Region).<br />
<br />
If construction staff receives a complaint involving an MDOT employee or other persons who are not employees of contractors on a project, they are to contact the MDOT Title VI Coordinator.<br />
<br />
Construction staff is to evaluate any problems or issues encountered with EEO, DBE or Title VI compliance when completing contractor performance evaluations.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#On-The-Job Training|On-The-Job Training]]===<br />
<br />
MDOT’s OJT program is based on requirements of Appendix B to Subpart A of Title 23 Code of Federal Regulations Part 230 (23 CFR Part 230), which requires inclusion of training special provisions in federal-aid construction contracts. The OJT program provides opportunities for unskilled workers to acquire training in skilled construction trades. The primary objective of the OJT program is to train and upgrade minorities, women, and disadvantaged persons toward full journey-level status and to provide opportunities for trainees to become part of a contractor’s permanent workforce. OJT program details are available from MDOT’s OBD or on the web at http://michigan.gov/ojt.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#Disadvantages Business Enterprises (DBE)|Disadvantages Business Enterprises (DBE)]]===<br />
<br />
DBE companies are contractors (prime, sub, sub-sub, etc.), truckers, materials suppliers, consultants and other service providers who are certified as having met requirements of 49 CFR Part 26. A current list of all DBE companies certified to work in Michigan by work classification and work type is available at: http://www.michigan.gov/mucp<br />
<br />
The document titled, 2013 DBE Program Procedures, is MDOT’s federally-approved plan for its DBE program. This document contains detailed information and is available at http://www.michigan.gov/mdotdbe under the Resources link.<br />
<br />
DBE race-conscious (RC) participation goals are expressed as a percentage of work which must be contracted to DBE companies for applicable projects with a DBE goal. On RC projects the prime contractor is required to provide DBE commitment sheets ([http://mdotcf.state.mi.us/public/webforms/public/0178.pdf Form 0178], Disadvantaged Business Enterprise (DBE) Participation) prior to contract award. The construction/project engineer is notified via email (or file presence in ProjectWise) of the prime contractor DBE commitments on RC projects or when there are changes in the goal or DBE companies committed to the project. These notifications are to be provided to construction staff assigned to the project. DBE commitments, subcontracts, and the current DBE goal (when applicable) assigned to a project are posted on MDOT’s Construction Contract Inquiry website at http://mdotcf.state.mi.us/public/trnsport/.<br />
<br />
The following tasks related to DBE oversight are to be completed on all federally funded projects. The task list provides guidance to project construction staff related to their responsibilities for oversight of DBE compliance.<br />
<br />
1.Collect all DBE subcontracts and purchase orders from prime contractor. Provide copies of purchase orders to OBD with the respective [http://mdotcf.state.mi.us/public/webforms/public/4109.pdf 4109 form] submittal.<br />
<br />
2.Review DBE commitment sheets ([http://mdotcf.state.mi.us/public/webforms/public/0178.pdf form 0178], also known as blue sheets) for awareness and knowledge.<br />
<br />
3.Monitor and document DBE work operations.<br />
<br />
4.Monitor and document Commercially Useful Function (CUF) compliance ([http://mdotcf.state.mi.us/public/webforms/public/4109.pdf form 4109]) during construction operations and provide a copy of [http://mdotcf.state.mi.us/public/webforms/public/4109.pdf form 4109] to OBD as noted on the form.<br />
<br />
5.Monitor compliance with DBE commitments (work type, amounts committed, DBE payments, etc.).<br />
<br />
6.Monitor overall DBE participation percentage as construction work progresses.<br />
<br />
7.Calculate the final overall DBE participation percentage to check for compliance with the contract requirements. Contact OBD with non-compliance issues.<br />
<br />
8.Document all DBE contracting issues, concerns, problems, etc. and provide to OBD for discussion and resolution.<br />
<br />
9.Provide all DBE substitution forms in accordance with form instructions and distribution lists.<br />
<br />
When the construction/project engineer becomes aware that a DBE goal will not be met due to the inability of a DBE to perform work, changes in DBE subcontracting, reduced quantities, changes in the work, etc., the construction/project engineer must direct the contractor to submit a specific plan to address the goal deficiency to the engineer. The construction/project engineer will provide a copy of the submitted plan to OBD.<br />
<br />
The contractor may, after award, request a waiver or modification of the DBE participation goal. The contractor must submit evidence of good faith efforts to meet the DBE participation goal. This includes documentation to support that the amount of contract work remaining was carefully reviewed to identify other work which could be subcontracted to DBE firms.<br />
<br />
If the prime contractor is not meeting its RC DBE participation goal after project award, it must request a post award waiver or modification of the goal. These requests are to be submitted with [http://mdotcf.state.mi.us/public/webforms/public/0188.pdf Form 0188], Contractor Good Faith Effort Application. Requests for waiver or modification of a DBE participation goal must be submitted to OBD immediately upon awareness.<br />
<br />
Contractors are not allowed to arbitrarily reduce the amount of work committed to DBE companies or terminate a DBE subcontractor without construction/project engineer approval, including the self performance of previously committed DBE work. The construction/project engineer is to be notified of a DBE company’s inability to perform work and the contractor’s intent to obtain a substitute DBE on projects with race-conscious (RC) DBE participation goals. A DBE who is unable to perform work must be given five business days written notice by the contractor of their intent to obtain a substitute DBE. The contractor is required to provide copies of the notice to the construction/project engineer and OBD. To substitute DBE companies, the prime contractor must then submit Form 0196, Request to Replace Disadvantaged Business Enterprise. The construction/project engineer must review and approve (in consultation with OBD) any DBE substitutions before submitting the approved form to the MDOT Contract Services Division.<br />
<br />
Work items, if applicable and available, must be properly assigned in FieldManager to the respective DBE company. Construction staff must document work done by all DBE companies, including truckers, suppliers, service providers, and subcontractors. Documentation is to occur on the Inspector Daily Reports (IDR) or the Commercially Useful Function [http://mdotcf.state.mi.us/public/webforms/public/4109.pdf Form 4109] submittal and should include any concerns or problems. All potential field concerns are to be discussed with OBD staff.<br />
<br />
{{top}}<br />
<br />
===[[#DBE Construction Engineers and Technicians|DBE Construction Engineers and Technicians]]===<br />
<br />
MDOT has assigned construction engineers and technicians by region to help DBE companies bidding or working on construction contracts. The DBE Technician list is available at: http://www.michigan.gov/mdotdbe under the contacts heading.<br />
<br />
{{top}}<br />
===[[#Third Party Complaints|Third Party Complaints]]===<br />
<br />
Any person may file a written complaint alleging that a currently certified firm is in violation of DBE regulations. Complaints must be filed with OBD in writing no later than 180 days after the date of an alleged violation. For further information, refer to the DBE Program Procedures as discussed previously.<br />
<br />
{{top}}<br />
===[[#DBE Commercially Useful Function (CUF) Requirements|DBE Commercially Useful Function (CUF) Requirements]]===<br />
<br />
Field direction on this issue can be reviewed with Bureau of Highway Instructional Memorandum, 2013-12, Disadvantaged Business Enterprise (DBE) Commercially Useful Function (CUF) Compliance or any applicable superseding BOHIM.<br />
<br />
{{top}}<br />
<br />
===[[#Joint Checks|Joint Checks]]===<br />
<br />
A joint check is a two party check between a subcontractor, a prime contractor, and a materials supplier. Joint check arrangements must be approved by OBD and the Contract Services Division in advance of use. MDOT Form 0183, Application to Use Joint Checks, is included in project proposals and must be submitted to the OBD for approval at least two weeks in advance of use of any joint checks.<br />
<br />
{{top}}<br />
<br />
===[[#DBE Documentation| DBE Documentation]]===<br />
<br />
The construction/project engineer should compare names of DBE companies and payments listed via submittal of form 2124A with the following items to check for discrepancies or compliance issues:<br />
<br />
*DBE companies listed on MDOT Form 0178, Disadvantaged Business Enterprise (DBE) Participation.<br />
*The types of work listed on forms 0178 or 0182 with the services/work classification listed on form 2124A.<br />
*Project scheduling and anticipated work presence by DBE companies.<br />
*Any reports of non-compliance with prompt payment requirements.<br />
<br />
Construction/Project engineers should question any deductions shown on form 2124A. Contractors are not permitted to hold any type of retainage per MDOT policy. Holding of retainage or making partial payment to subcontractors for work that was approved and paid by MDOT is to be reported to the Construction Field Services Division.<br />
<br />
{{top}}<br />
<br />
===[[#Questions|Questions]]===<br />
<br />
OBD can be contacted at MDOT-DBE@michigan.gov with any DBE related questions or concerns. Messages can be left at 866-323-1264 or 866-323-4009 and an OBD staff person will respond.<br />
<br />
Please share this information with consultants and local agencies in your area. If you have any questions, please contact Jason Gutting, Engineer of Construction Operations, at [mailto:guttingj@michigan.gov Jason Gutting] or 517-636-6334.<br />
<br />
{{top}}<br />
<br />
===[[#Construction Manual| Construction Manual]]===<br />
<br />
The contents of this BOHIM will be placed and maintained in the MDOT Construction Manual. After incorporation the BOHIM will sunset and link directly to the Construction Manual.<br />
<br />
{{top}}<br />
<br />
[[Category: Construction Manual]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=Disadvantaged_Business_Enterprises_(DBE)&diff=3861Disadvantaged Business Enterprises (DBE)2014-11-10T19:39:18Z<p>HarrisR18: /* Disadvantages Business Enterprises (DBE) */</p>
<hr />
<div>===[[#Equal Employment Opportunity|Equal Employment Opportunity]]===<br />
<br />
MDOT must ensure that all federal-aid contractors, sub-contractors, vendors, and material suppliers do not discriminate in employment and contracting practices based on race, color, religion (in the context of employment), sex, national origin, age, or disability.<br />
<br />
Any deficiencies noted in a contractor’s EEO program are to be provided to the [mailto:MDOT-DBE@michigan.gov MDOT Office of Business Development (OBD)] at 866-323-1264.<br />
<br />
A contractor’s affirmative action plan is to be comprised of the following contractual requirements: EO provisions, training provisions, Federal Highway Administration (FHWA) Form 1273, Title VI (under Appendix C of the project proposal) and Disadvantaged Business Enterprise (DBE) goals and provisions.<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Coordinator|Title VI Coordinator]]=== <br />
<br />
Cheryl Hudson is MDOT’s Title VI Coordinator. She can be contacted at 517-373-0980 or at [mailto:HudsonC1@michigan.gov Cheryl Hudson] for any issues related to civil rights.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Definition|Title VI Definition]]===<br />
<br />
No person in the United States shall, on the grounds of race, color, or national origin, be excluded from participation in, be denied the benefits of, or be otherwise subjected to discrimination under any program or activity funded in whole or in part with federal funds.<br />
<br />
{{top}}<br />
<br />
===[[#Equal Opprotunity (EO) Contract Compliance|Equal Opprotunity (EO) Contract Compliance]]===<br />
<br />
MDOT’s OBD conducts federally-required EO and EEO compliance reviews as part of its monitoring responsibilities. OBD staff determines whether the contractor took all necessary and reasonable steps to comply with these requirements.<br />
<br />
EO requirements in FHWA, Form 1273, Required Contract Provisions Federal-Aid Construction Contracts, apply to all contractors, subcontractors, vendors and suppliers on all federal-aid contracts of $10,000 or more. As specified in FHWA Form 1273, the contractor (or subcontractor) must include this form in each subcontract and further require its inclusion in all lower tier subcontracts (excluding purchase orders, rental agreements and other agreements for supplies or services).<br />
<br />
FHWA Form 1273 is to be physically incorporated in each federal-aid highway construction contract and subcontract. Form 1273 may be bound electronically into an electronic contract/subcontract (PDF format) but may not be left out and only referenced (website location, etc.) as it must be physically included in every contract/subcontract. The construction/project engineer should discuss FHWA Form 1273 at the preconstruction meeting.<br />
<br />
The construction/project engineer must ensure that contractors EO posters are in order and conspicuously placed on the project site as the FHWA requires contractors to prominently display posters in areas available to employees and applicants for employment during the life of the project. The poster display is to include the prime contractor’s EEO policy statement and the name and contact information of the prime’s EEO Officer. All notices and posters are to be legible, protected from the elements, and the dates must be shown. Mobile operations can have the posters located in a vehicle. Complete [http://mdotcf.state.mi.us/public/webforms/public/1967.pdf Form 1967], Jobsite Poster Inspection Checklist, at the start of construction operations and any time the poster display is moved. The form is an aid to make sure that the contractor is following the proper procedure and is to be placed in the project files after completion of the form.<br />
<br />
Job site posters should be discussed at the preconstruction meeting. The required job site posting information can be found under Section C at the following MDOT website: http://www.michigan.gov/mdot/0,4616,7-151-9622_11044_11367-222170--,00.html. <br />
<br />
<br />
If construction staff receives a complaint from the employee of a contractor or subcontractor they are to notify through email [mailto:DBE@michigan.gov OBD] or call at 866-323-1264 (all MDOT Regions except Metro) or 866-323-4009 (Metro Region).<br />
<br />
If construction staff receives a complaint involving an MDOT employee or other persons who are not employees of contractors on a project, they are to contact the MDOT Title VI Coordinator.<br />
<br />
Construction staff is to evaluate any problems or issues encountered with EEO, DBE or Title VI compliance when completing contractor performance evaluations.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#On-The-Job Training|On-The-Job Training]]===<br />
<br />
MDOT’s OJT program is based on requirements of Appendix B to Subpart A of Title 23 Code of Federal Regulations Part 230 (23 CFR Part 230), which requires inclusion of training special provisions in federal-aid construction contracts. The OJT program provides opportunities for unskilled workers to acquire training in skilled construction trades. The primary objective of the OJT program is to train and upgrade minorities, women, and disadvantaged persons toward full journey-level status and to provide opportunities for trainees to become part of a contractor’s permanent workforce. OJT program details are available from MDOT’s OBD or on the web at http://michigan.gov/ojt.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#Disadvantages Business Enterprises (DBE)|Disadvantages Business Enterprises (DBE)]]===<br />
<br />
DBE companies are contractors (prime, sub, sub-sub, etc.), truckers, materials suppliers, consultants and other service providers who are certified as having met requirements of 49 CFR Part 26. A current list of all DBE companies certified to work in Michigan by work classification and work type is available at: http://www.michigan.gov/mucp<br />
<br />
The document titled, 2013 DBE Program Procedures, is MDOT’s federally-approved plan for its DBE program. This document contains detailed information and is available at http://www.michigan.gov/mdotdbe under the Resources link.<br />
<br />
DBE race-conscious (RC) participation goals are expressed as a percentage of work which must be contracted to DBE companies for applicable projects with a DBE goal. On RC projects the prime contractor is required to provide DBE commitment sheets ([http://mdotcf.state.mi.us/public/webforms/public/0178.pdf Form 0178], Disadvantaged Business Enterprise (DBE) Participation) prior to contract award. The construction/project engineer is notified via email (or file presence in ProjectWise) of the prime contractor DBE commitments on RC projects or when there are changes in the goal or DBE companies committed to the project. These notifications are to be provided to construction staff assigned to the project. DBE commitments, subcontracts, and the current DBE goal (when applicable) assigned to a project are posted on MDOT’s Construction Contract Inquiry website at http://mdotcf.state.mi.us/public/trnsport/.<br />
<br />
The following tasks related to DBE oversight are to be completed on all federally funded projects. The task list provides guidance to project construction staff related to their responsibilities for oversight of DBE compliance.<br />
<br />
1.Collect all DBE subcontracts and purchase orders from prime contractor. Provide copies of purchase orders to OBD with the respective [http://mdotcf.state.mi.us/public/webforms/public/4109.pdf 4109 form] submittal.<br />
<br />
2.Review DBE commitment sheets ([http://mdotcf.state.mi.us/public/webforms/public/0178.pdf form 0178], also known as blue sheets) for awareness and knowledge.<br />
<br />
3.Monitor and document DBE work operations.<br />
<br />
4.Monitor and document Commercially Useful Function (CUF) compliance ([http://mdotcf.state.mi.us/public/webforms/public/4109.pdf form 4109]) during construction operations and provide a copy of [http://mdotcf.state.mi.us/public/webforms/public/4109.pdf form 4109] to OBD as noted on the form.<br />
<br />
5.Monitor compliance with DBE commitments (work type, amounts committed, DBE payments, etc.).<br />
<br />
6.Monitor overall DBE participation percentage as construction work progresses.<br />
<br />
7.Calculate the final overall DBE participation percentage to check for compliance with the contract requirements. Contact OBD with non-compliance issues.<br />
<br />
8.Document all DBE contracting issues, concerns, problems, etc. and provide to OBD for discussion and resolution.<br />
<br />
9.Provide all DBE substitution forms in accordance with form instructions and distribution lists.<br />
<br />
When the construction/project engineer becomes aware that a DBE goal will not be met due to the inability of a DBE to perform work, changes in DBE subcontracting, reduced quantities, changes in the work, etc., the construction/project engineer must direct the contractor to submit a specific plan to address the goal deficiency to the engineer. The construction/project engineer will provide a copy of the submitted plan to OBD.<br />
<br />
The contractor may, after award, request a waiver or modification of the DBE participation goal. The contractor must submit evidence of good faith efforts to meet the DBE participation goal. This includes documentation to support that the amount of contract work remaining was carefully reviewed to identify other work which could be subcontracted to DBE firms.<br />
<br />
If the prime contractor is not meeting its RC DBE participation goal after project award, it must request a post award waiver or modification of the goal. These requests are to be submitted with [http://mdotcf.state.mi.us/public/webforms/public/0188.pdf Form 0188], Contractor Good Faith Effort Application. Requests for waiver or modification of a DBE participation goal must be submitted to OBD immediately upon awareness.<br />
<br />
Contractors are not allowed to arbitrarily reduce the amount of work committed to DBE companies or terminate a DBE subcontractor without construction/project engineer approval, including the self performance of previously committed DBE work. The construction/project engineer is to be notified of a DBE company’s inability to perform work and the contractor’s intent to obtain a substitute DBE on projects with race-conscious (RC) DBE participation goals. A DBE who is unable to perform work must be given five business days written notice by the contractor of their intent to obtain a substitute DBE. The contractor is required to provide copies of the notice to the construction/project engineer and OBD. To substitute DBE companies, the prime contractor must then submit Form 0196, Request to Replace Disadvantaged Business Enterprise. The construction/project engineer must review and approve (in consultation with OBD) any DBE substitutions before submitting the approved form to the MDOT Contract Services Division.<br />
<br />
Work items, if applicable and available, must be properly assigned in FieldManager to the respective DBE company. Construction staff must document work done by all DBE companies, including truckers, suppliers, service providers, and subcontractors. Documentation is to occur on the Inspector Daily Reports (IDR) or the Commercially Useful Function Form 4109 submittal and should include any concerns or problems. All potential field concerns are to be discussed with OBD staff.<br />
<br />
{{top}}<br />
<br />
===[[#DBE Construction Engineers and Technicians|DBE Construction Engineers and Technicians]]===<br />
<br />
MDOT has assigned construction engineers and technicians by region to help DBE companies bidding or working on construction contracts. The DBE Technician list is available at: http://www.michigan.gov/mdotdbe under the contacts heading.<br />
<br />
{{top}}<br />
===[[#Third Party Complaints|Third Party Complaints]]===<br />
<br />
Any person may file a written complaint alleging that a currently certified firm is in violation of DBE regulations. Complaints must be filed with OBD in writing no later than 180 days after the date of an alleged violation. For further information, refer to the DBE Program Procedures as discussed previously.<br />
<br />
{{top}}<br />
===[[#DBE Commercially Useful Function (CUF) Requirements|DBE Commercially Useful Function (CUF) Requirements]]===<br />
<br />
Field direction on this issue can be reviewed with Bureau of Highway Instructional Memorandum, 2013-12, Disadvantaged Business Enterprise (DBE) Commercially Useful Function (CUF) Compliance or any applicable superseding BOHIM.<br />
<br />
{{top}}<br />
<br />
===[[#Joint Checks|Joint Checks]]===<br />
<br />
A joint check is a two party check between a subcontractor, a prime contractor, and a materials supplier. Joint check arrangements must be approved by OBD and the Contract Services Division in advance of use. MDOT Form 0183, Application to Use Joint Checks, is included in project proposals and must be submitted to the OBD for approval at least two weeks in advance of use of any joint checks.<br />
<br />
{{top}}<br />
<br />
===[[#DBE Documentation| DBE Documentation]]===<br />
<br />
The construction/project engineer should compare names of DBE companies and payments listed via submittal of form 2124A with the following items to check for discrepancies or compliance issues:<br />
<br />
*DBE companies listed on MDOT Form 0178, Disadvantaged Business Enterprise (DBE) Participation.<br />
*The types of work listed on forms 0178 or 0182 with the services/work classification listed on form 2124A.<br />
*Project scheduling and anticipated work presence by DBE companies.<br />
*Any reports of non-compliance with prompt payment requirements.<br />
<br />
Construction/Project engineers should question any deductions shown on form 2124A. Contractors are not permitted to hold any type of retainage per MDOT policy. Holding of retainage or making partial payment to subcontractors for work that was approved and paid by MDOT is to be reported to the Construction Field Services Division.<br />
<br />
{{top}}<br />
<br />
===[[#Questions|Questions]]===<br />
<br />
OBD can be contacted at MDOT-DBE@michigan.gov with any DBE related questions or concerns. Messages can be left at 866-323-1264 or 866-323-4009 and an OBD staff person will respond.<br />
<br />
Please share this information with consultants and local agencies in your area. If you have any questions, please contact Jason Gutting, Engineer of Construction Operations, at [mailto:guttingj@michigan.gov Jason Gutting] or 517-636-6334.<br />
<br />
{{top}}<br />
<br />
===[[#Construction Manual| Construction Manual]]===<br />
<br />
The contents of this BOHIM will be placed and maintained in the MDOT Construction Manual. After incorporation the BOHIM will sunset and link directly to the Construction Manual.<br />
<br />
{{top}}<br />
<br />
[[Category: Construction Manual]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=Disadvantaged_Business_Enterprises_(DBE)&diff=3860Disadvantaged Business Enterprises (DBE)2014-11-10T19:35:42Z<p>HarrisR18: /* Equal Opprotunity (EO) Contract Compliance */</p>
<hr />
<div>===[[#Equal Employment Opportunity|Equal Employment Opportunity]]===<br />
<br />
MDOT must ensure that all federal-aid contractors, sub-contractors, vendors, and material suppliers do not discriminate in employment and contracting practices based on race, color, religion (in the context of employment), sex, national origin, age, or disability.<br />
<br />
Any deficiencies noted in a contractor’s EEO program are to be provided to the [mailto:MDOT-DBE@michigan.gov MDOT Office of Business Development (OBD)] at 866-323-1264.<br />
<br />
A contractor’s affirmative action plan is to be comprised of the following contractual requirements: EO provisions, training provisions, Federal Highway Administration (FHWA) Form 1273, Title VI (under Appendix C of the project proposal) and Disadvantaged Business Enterprise (DBE) goals and provisions.<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Coordinator|Title VI Coordinator]]=== <br />
<br />
Cheryl Hudson is MDOT’s Title VI Coordinator. She can be contacted at 517-373-0980 or at [mailto:HudsonC1@michigan.gov Cheryl Hudson] for any issues related to civil rights.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Definition|Title VI Definition]]===<br />
<br />
No person in the United States shall, on the grounds of race, color, or national origin, be excluded from participation in, be denied the benefits of, or be otherwise subjected to discrimination under any program or activity funded in whole or in part with federal funds.<br />
<br />
{{top}}<br />
<br />
===[[#Equal Opprotunity (EO) Contract Compliance|Equal Opprotunity (EO) Contract Compliance]]===<br />
<br />
MDOT’s OBD conducts federally-required EO and EEO compliance reviews as part of its monitoring responsibilities. OBD staff determines whether the contractor took all necessary and reasonable steps to comply with these requirements.<br />
<br />
EO requirements in FHWA, Form 1273, Required Contract Provisions Federal-Aid Construction Contracts, apply to all contractors, subcontractors, vendors and suppliers on all federal-aid contracts of $10,000 or more. As specified in FHWA Form 1273, the contractor (or subcontractor) must include this form in each subcontract and further require its inclusion in all lower tier subcontracts (excluding purchase orders, rental agreements and other agreements for supplies or services).<br />
<br />
FHWA Form 1273 is to be physically incorporated in each federal-aid highway construction contract and subcontract. Form 1273 may be bound electronically into an electronic contract/subcontract (PDF format) but may not be left out and only referenced (website location, etc.) as it must be physically included in every contract/subcontract. The construction/project engineer should discuss FHWA Form 1273 at the preconstruction meeting.<br />
<br />
The construction/project engineer must ensure that contractors EO posters are in order and conspicuously placed on the project site as the FHWA requires contractors to prominently display posters in areas available to employees and applicants for employment during the life of the project. The poster display is to include the prime contractor’s EEO policy statement and the name and contact information of the prime’s EEO Officer. All notices and posters are to be legible, protected from the elements, and the dates must be shown. Mobile operations can have the posters located in a vehicle. Complete [http://mdotcf.state.mi.us/public/webforms/public/1967.pdf Form 1967], Jobsite Poster Inspection Checklist, at the start of construction operations and any time the poster display is moved. The form is an aid to make sure that the contractor is following the proper procedure and is to be placed in the project files after completion of the form.<br />
<br />
Job site posters should be discussed at the preconstruction meeting. The required job site posting information can be found under Section C at the following MDOT website: http://www.michigan.gov/mdot/0,4616,7-151-9622_11044_11367-222170--,00.html. <br />
<br />
<br />
If construction staff receives a complaint from the employee of a contractor or subcontractor they are to notify through email [mailto:DBE@michigan.gov OBD] or call at 866-323-1264 (all MDOT Regions except Metro) or 866-323-4009 (Metro Region).<br />
<br />
If construction staff receives a complaint involving an MDOT employee or other persons who are not employees of contractors on a project, they are to contact the MDOT Title VI Coordinator.<br />
<br />
Construction staff is to evaluate any problems or issues encountered with EEO, DBE or Title VI compliance when completing contractor performance evaluations.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#On-The-Job Training|On-The-Job Training]]===<br />
<br />
MDOT’s OJT program is based on requirements of Appendix B to Subpart A of Title 23 Code of Federal Regulations Part 230 (23 CFR Part 230), which requires inclusion of training special provisions in federal-aid construction contracts. The OJT program provides opportunities for unskilled workers to acquire training in skilled construction trades. The primary objective of the OJT program is to train and upgrade minorities, women, and disadvantaged persons toward full journey-level status and to provide opportunities for trainees to become part of a contractor’s permanent workforce. OJT program details are available from MDOT’s OBD or on the web at http://michigan.gov/ojt.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#Disadvantages Business Enterprises (DBE)|Disadvantages Business Enterprises (DBE)]]===<br />
<br />
DBE companies are contractors (prime, sub, sub-sub, etc.), truckers, materials suppliers, consultants and other service providers who are certified as having met requirements of 49 CFR Part 26. A current list of all DBE companies certified to work in Michigan by work classification and work type is available at: http://www.michigan.gov/mucp<br />
<br />
The document titled, 2013 DBE Program Procedures, is MDOT’s federally-approved plan for its DBE program. This document contains detailed information and is available at http://www.michigan.gov/mdotdbe under the Resources link.<br />
<br />
DBE race-conscious (RC) participation goals are expressed as a percentage of work which must be contracted to DBE companies for applicable projects with a DBE goal. On RC projects the prime contractor is required to provide DBE commitment sheets (Form 0178, Disadvantaged Business Enterprise (DBE) Participation) prior to contract award. The construction/project engineer is notified via email (or file presence in ProjectWise) of the prime contractor DBE commitments on RC projects or when there are changes in the goal or DBE companies committed to the project. These notifications are to be provided to construction staff assigned to the project. DBE commitments, subcontracts, and the current DBE goal (when applicable) assigned to a project are posted on MDOT’s Construction Contract Inquiry website at http://mdotcf.state.mi.us/public/trnsport/.<br />
<br />
The following tasks related to DBE oversight are to be completed on all federally funded projects. The task list provides guidance to project construction staff related to their responsibilities for oversight of DBE compliance.<br />
<br />
1.Collect all DBE subcontracts and purchase orders from prime contractor. Provide copies of purchase orders to OBD with the respective 4109 form submittal.<br />
<br />
2.Review DBE commitment sheets (form 0178, also known as blue sheets) for awareness and knowledge.<br />
<br />
3.Monitor and document DBE work operations.<br />
<br />
4.Monitor and document Commercially Useful Function (CUF) compliance (form 4109) during construction operations and provide a copy of form 4109 to OBD as noted on the form.<br />
<br />
5.Monitor compliance with DBE commitments (work type, amounts committed, DBE payments, etc.).<br />
<br />
6.Monitor overall DBE participation percentage as construction work progresses.<br />
<br />
7.Calculate the final overall DBE participation percentage to check for compliance with the contract requirements. Contact OBD with non-compliance issues.<br />
<br />
8.Document all DBE contracting issues, concerns, problems, etc. and provide to OBD for discussion and resolution.<br />
<br />
9.Provide all DBE substitution forms in accordance with form instructions and distribution lists.<br />
<br />
When the construction/project engineer becomes aware that a DBE goal will not be met due to the inability of a DBE to perform work, changes in DBE subcontracting, reduced quantities, changes in the work, etc., the construction/project engineer must direct the contractor to submit a specific plan to address the goal deficiency to the engineer. The construction/project engineer will provide a copy of the submitted plan to OBD.<br />
<br />
The contractor may, after award, request a waiver or modification of the DBE participation goal. The contractor must submit evidence of good faith efforts to meet the DBE participation goal. This includes documentation to support that the amount of contract work remaining was carefully reviewed to identify other work which could be subcontracted to DBE firms.<br />
<br />
If the prime contractor is not meeting its RC DBE participation goal after project award, it must request a post award waiver or modification of the goal. These requests are to be submitted with Form 0188, Contractor Good Faith Effort Application. Requests for waiver or modification of a DBE participation goal must be submitted to OBD immediately upon awareness.<br />
<br />
Contractors are not allowed to arbitrarily reduce the amount of work committed to DBE companies or terminate a DBE subcontractor without construction/project engineer approval, including the self performance of previously committed DBE work. The construction/project engineer is to be notified of a DBE company’s inability to perform work and the contractor’s intent to obtain a substitute DBE on projects with race-conscious (RC) DBE participation goals. A DBE who is unable to perform work must be given five business days written notice by the contractor of their intent to obtain a substitute DBE. The contractor is required to provide copies of the notice to the construction/project engineer and OBD. To substitute DBE companies, the prime contractor must then submit Form 0196, Request to Replace Disadvantaged Business Enterprise. The construction/project engineer must review and approve (in consultation with OBD) any DBE substitutions before submitting the approved form to the MDOT Contract Services Division.<br />
<br />
Work items, if applicable and available, must be properly assigned in FieldManager to the respective DBE company. Construction staff must document work done by all DBE companies, including truckers, suppliers, service providers, and subcontractors. Documentation is to occur on the Inspector Daily Reports (IDR) or the Commercially Useful Function Form 4109 submittal and should include any concerns or problems. All potential field concerns are to be discussed with OBD staff.<br />
<br />
{{top}}<br />
<br />
===[[#DBE Construction Engineers and Technicians|DBE Construction Engineers and Technicians]]===<br />
<br />
MDOT has assigned construction engineers and technicians by region to help DBE companies bidding or working on construction contracts. The DBE Technician list is available at: http://www.michigan.gov/mdotdbe under the contacts heading.<br />
<br />
{{top}}<br />
===[[#Third Party Complaints|Third Party Complaints]]===<br />
<br />
Any person may file a written complaint alleging that a currently certified firm is in violation of DBE regulations. Complaints must be filed with OBD in writing no later than 180 days after the date of an alleged violation. For further information, refer to the DBE Program Procedures as discussed previously.<br />
<br />
{{top}}<br />
===[[#DBE Commercially Useful Function (CUF) Requirements|DBE Commercially Useful Function (CUF) Requirements]]===<br />
<br />
Field direction on this issue can be reviewed with Bureau of Highway Instructional Memorandum, 2013-12, Disadvantaged Business Enterprise (DBE) Commercially Useful Function (CUF) Compliance or any applicable superseding BOHIM.<br />
<br />
{{top}}<br />
<br />
===[[#Joint Checks|Joint Checks]]===<br />
<br />
A joint check is a two party check between a subcontractor, a prime contractor, and a materials supplier. Joint check arrangements must be approved by OBD and the Contract Services Division in advance of use. MDOT Form 0183, Application to Use Joint Checks, is included in project proposals and must be submitted to the OBD for approval at least two weeks in advance of use of any joint checks.<br />
<br />
{{top}}<br />
<br />
===[[#DBE Documentation| DBE Documentation]]===<br />
<br />
The construction/project engineer should compare names of DBE companies and payments listed via submittal of form 2124A with the following items to check for discrepancies or compliance issues:<br />
<br />
*DBE companies listed on MDOT Form 0178, Disadvantaged Business Enterprise (DBE) Participation.<br />
*The types of work listed on forms 0178 or 0182 with the services/work classification listed on form 2124A.<br />
*Project scheduling and anticipated work presence by DBE companies.<br />
*Any reports of non-compliance with prompt payment requirements.<br />
<br />
Construction/Project engineers should question any deductions shown on form 2124A. Contractors are not permitted to hold any type of retainage per MDOT policy. Holding of retainage or making partial payment to subcontractors for work that was approved and paid by MDOT is to be reported to the Construction Field Services Division.<br />
<br />
{{top}}<br />
<br />
===[[#Questions|Questions]]===<br />
<br />
OBD can be contacted at MDOT-DBE@michigan.gov with any DBE related questions or concerns. Messages can be left at 866-323-1264 or 866-323-4009 and an OBD staff person will respond.<br />
<br />
Please share this information with consultants and local agencies in your area. If you have any questions, please contact Jason Gutting, Engineer of Construction Operations, at [mailto:guttingj@michigan.gov Jason Gutting] or 517-636-6334.<br />
<br />
{{top}}<br />
<br />
===[[#Construction Manual| Construction Manual]]===<br />
<br />
The contents of this BOHIM will be placed and maintained in the MDOT Construction Manual. After incorporation the BOHIM will sunset and link directly to the Construction Manual.<br />
<br />
{{top}}<br />
<br />
[[Category: Construction Manual]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=Disadvantaged_Business_Enterprises_(DBE)&diff=3841Disadvantaged Business Enterprises (DBE)2014-11-03T20:25:12Z<p>HarrisR18: /* Questions */</p>
<hr />
<div>===[[#Equal Employment Opportunity|Equal Employment Opportunity]]===<br />
<br />
MDOT must ensure that all federal-aid contractors, sub-contractors, vendors, and material suppliers do not discriminate in employment and contracting practices based on race, color, religion (in the context of employment), sex, national origin, age, or disability.<br />
<br />
Any deficiencies noted in a contractor’s EEO program are to be provided to the [mailto:MDOT-DBE@michigan.gov MDOT Office of Business Development (OBD)] at 866-323-1264.<br />
<br />
A contractor’s affirmative action plan is to be comprised of the following contractual requirements: EO provisions, training provisions, Federal Highway Administration (FHWA) Form 1273, Title VI (under Appendix C of the project proposal) and Disadvantaged Business Enterprise (DBE) goals and provisions.<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Coordinator|Title VI Coordinator]]=== <br />
<br />
Cheryl Hudson is MDOT’s Title VI Coordinator. She can be contacted at 517-373-0980 or at [mailto:HudsonC1@michigan.gov Cheryl Hudson] for any issues related to civil rights.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Definition|Title VI Definition]]===<br />
<br />
No person in the United States shall, on the grounds of race, color, or national origin, be excluded from participation in, be denied the benefits of, or be otherwise subjected to discrimination under any program or activity funded in whole or in part with federal funds.<br />
<br />
{{top}}<br />
<br />
===[[#Equal Opprotunity (EO) Contract Compliance|Equal Opprotunity (EO) Contract Compliance]]===<br />
<br />
MDOT’s OBD conducts federally-required EO and EEO compliance reviews as part of its monitoring responsibilities. OBD staff determines whether the contractor took all necessary and reasonable steps to comply with these requirements.<br />
<br />
EO requirements in FHWA, Form 1273, Required Contract Provisions Federal-Aid Construction Contracts, apply to all contractors, subcontractors, vendors and suppliers on all federal-aid contracts of $10,000 or more. As specified in FHWA Form 1273, the contractor (or subcontractor) must include this form in each subcontract and further require its inclusion in all lower tier subcontracts (excluding purchase orders, rental agreements and other agreements for supplies or services).<br />
<br />
FHWA Form 1273 is to be physically incorporated in each federal-aid highway construction contract and subcontract. Form 1273 may be bound electronically into an electronic contract/subcontract (PDF format) but may not be left out and only referenced (website location, etc.) as it must be physically included in every contract/subcontract. The construction/project engineer should discuss FHWA Form 1273 at the preconstruction meeting.<br />
<br />
The construction/project engineer must ensure that contractors EO posters are in order and conspicuously placed on the project site as the FHWA requires contractors to prominently display posters in areas available to employees and applicants for employment during the life of the project. The poster display is to include the prime contractor’s EEO policy statement and the name and contact information of the prime’s EEO Officer. All notices and posters are to be legible, protected from the elements, and the dates must be shown. Mobile operations can have the posters located in a vehicle. Complete Form 1967, Jobsite Poster Inspection Checklist, at the start of construction operations and any time the poster display is moved. The form is an aid to make sure that the contractor is following the proper procedure and is to be placed in the project files after completion of the form.<br />
<br />
Job site posters should be discussed at the preconstruction meeting. The required job site posting information can be found under Section C at the following MDOT website: http://www.michigan.gov/mdot/0,4616,7-151-9622_11044_11367-222170--,00.html. <br />
<br />
<br />
If construction staff receives a complaint from the employee of a contractor or subcontractor they are to notify through email [mailto:DBE@michigan.gov OBD] or call at 866-323-1264 (all MDOT Regions except Metro) or 866-323-4009 (Metro Region).<br />
<br />
If construction staff receives a complaint involving an MDOT employee or other persons who are not employees of contractors on a project, they are to contact the MDOT Title VI Coordinator.<br />
<br />
Construction staff is to evaluate any problems or issues encountered with EEO, DBE or Title VI compliance when completing contractor performance evaluations.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#On-The-Job Training|On-The-Job Training]]===<br />
<br />
MDOT’s OJT program is based on requirements of Appendix B to Subpart A of Title 23 Code of Federal Regulations Part 230 (23 CFR Part 230), which requires inclusion of training special provisions in federal-aid construction contracts. The OJT program provides opportunities for unskilled workers to acquire training in skilled construction trades. The primary objective of the OJT program is to train and upgrade minorities, women, and disadvantaged persons toward full journey-level status and to provide opportunities for trainees to become part of a contractor’s permanent workforce. OJT program details are available from MDOT’s OBD or on the web at http://michigan.gov/ojt.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#Disadvantages Business Enterprises (DBE)|Disadvantages Business Enterprises (DBE)]]===<br />
<br />
DBE companies are contractors (prime, sub, sub-sub, etc.), truckers, materials suppliers, consultants and other service providers who are certified as having met requirements of 49 CFR Part 26. A current list of all DBE companies certified to work in Michigan by work classification and work type is available at: http://www.michigan.gov/mucp<br />
<br />
The document titled, 2013 DBE Program Procedures, is MDOT’s federally-approved plan for its DBE program. This document contains detailed information and is available at http://www.michigan.gov/mdotdbe under the Resources link.<br />
<br />
DBE race-conscious (RC) participation goals are expressed as a percentage of work which must be contracted to DBE companies for applicable projects with a DBE goal. On RC projects the prime contractor is required to provide DBE commitment sheets (Form 0178, Disadvantaged Business Enterprise (DBE) Participation) prior to contract award. The construction/project engineer is notified via email (or file presence in ProjectWise) of the prime contractor DBE commitments on RC projects or when there are changes in the goal or DBE companies committed to the project. These notifications are to be provided to construction staff assigned to the project. DBE commitments, subcontracts, and the current DBE goal (when applicable) assigned to a project are posted on MDOT’s Construction Contract Inquiry website at http://mdotcf.state.mi.us/public/trnsport/.<br />
<br />
The following tasks related to DBE oversight are to be completed on all federally funded projects. The task list provides guidance to project construction staff related to their responsibilities for oversight of DBE compliance.<br />
<br />
1.Collect all DBE subcontracts and purchase orders from prime contractor. Provide copies of purchase orders to OBD with the respective 4109 form submittal.<br />
<br />
2.Review DBE commitment sheets (form 0178, also known as blue sheets) for awareness and knowledge.<br />
<br />
3.Monitor and document DBE work operations.<br />
<br />
4.Monitor and document Commercially Useful Function (CUF) compliance (form 4109) during construction operations and provide a copy of form 4109 to OBD as noted on the form.<br />
<br />
5.Monitor compliance with DBE commitments (work type, amounts committed, DBE payments, etc.).<br />
<br />
6.Monitor overall DBE participation percentage as construction work progresses.<br />
<br />
7.Calculate the final overall DBE participation percentage to check for compliance with the contract requirements. Contact OBD with non-compliance issues.<br />
<br />
8.Document all DBE contracting issues, concerns, problems, etc. and provide to OBD for discussion and resolution.<br />
<br />
9.Provide all DBE substitution forms in accordance with form instructions and distribution lists.<br />
<br />
When the construction/project engineer becomes aware that a DBE goal will not be met due to the inability of a DBE to perform work, changes in DBE subcontracting, reduced quantities, changes in the work, etc., the construction/project engineer must direct the contractor to submit a specific plan to address the goal deficiency to the engineer. The construction/project engineer will provide a copy of the submitted plan to OBD.<br />
<br />
The contractor may, after award, request a waiver or modification of the DBE participation goal. The contractor must submit evidence of good faith efforts to meet the DBE participation goal. This includes documentation to support that the amount of contract work remaining was carefully reviewed to identify other work which could be subcontracted to DBE firms.<br />
<br />
If the prime contractor is not meeting its RC DBE participation goal after project award, it must request a post award waiver or modification of the goal. These requests are to be submitted with Form 0188, Contractor Good Faith Effort Application. Requests for waiver or modification of a DBE participation goal must be submitted to OBD immediately upon awareness.<br />
<br />
Contractors are not allowed to arbitrarily reduce the amount of work committed to DBE companies or terminate a DBE subcontractor without construction/project engineer approval, including the self performance of previously committed DBE work. The construction/project engineer is to be notified of a DBE company’s inability to perform work and the contractor’s intent to obtain a substitute DBE on projects with race-conscious (RC) DBE participation goals. A DBE who is unable to perform work must be given five business days written notice by the contractor of their intent to obtain a substitute DBE. The contractor is required to provide copies of the notice to the construction/project engineer and OBD. To substitute DBE companies, the prime contractor must then submit Form 0196, Request to Replace Disadvantaged Business Enterprise. The construction/project engineer must review and approve (in consultation with OBD) any DBE substitutions before submitting the approved form to the MDOT Contract Services Division.<br />
<br />
Work items, if applicable and available, must be properly assigned in FieldManager to the respective DBE company. Construction staff must document work done by all DBE companies, including truckers, suppliers, service providers, and subcontractors. Documentation is to occur on the Inspector Daily Reports (IDR) or the Commercially Useful Function Form 4109 submittal and should include any concerns or problems. All potential field concerns are to be discussed with OBD staff.<br />
<br />
{{top}}<br />
<br />
===[[#DBE Construction Engineers and Technicians|DBE Construction Engineers and Technicians]]===<br />
<br />
MDOT has assigned construction engineers and technicians by region to help DBE companies bidding or working on construction contracts. The DBE Technician list is available at: http://www.michigan.gov/mdotdbe under the contacts heading.<br />
<br />
{{top}}<br />
===[[#Third Party Complaints|Third Party Complaints]]===<br />
<br />
Any person may file a written complaint alleging that a currently certified firm is in violation of DBE regulations. Complaints must be filed with OBD in writing no later than 180 days after the date of an alleged violation. For further information, refer to the DBE Program Procedures as discussed previously.<br />
<br />
{{top}}<br />
===[[#DBE Commercially Useful Function (CUF) Requirements|DBE Commercially Useful Function (CUF) Requirements]]===<br />
<br />
Field direction on this issue can be reviewed with Bureau of Highway Instructional Memorandum, 2013-12, Disadvantaged Business Enterprise (DBE) Commercially Useful Function (CUF) Compliance or any applicable superseding BOHIM.<br />
<br />
{{top}}<br />
<br />
===[[#Joint Checks|Joint Checks]]===<br />
<br />
A joint check is a two party check between a subcontractor, a prime contractor, and a materials supplier. Joint check arrangements must be approved by OBD and the Contract Services Division in advance of use. MDOT Form 0183, Application to Use Joint Checks, is included in project proposals and must be submitted to the OBD for approval at least two weeks in advance of use of any joint checks.<br />
<br />
{{top}}<br />
<br />
===[[#DBE Documentation| DBE Documentation]]===<br />
<br />
The construction/project engineer should compare names of DBE companies and payments listed via submittal of form 2124A with the following items to check for discrepancies or compliance issues:<br />
<br />
*DBE companies listed on MDOT Form 0178, Disadvantaged Business Enterprise (DBE) Participation.<br />
*The types of work listed on forms 0178 or 0182 with the services/work classification listed on form 2124A.<br />
*Project scheduling and anticipated work presence by DBE companies.<br />
*Any reports of non-compliance with prompt payment requirements.<br />
<br />
Construction/Project engineers should question any deductions shown on form 2124A. Contractors are not permitted to hold any type of retainage per MDOT policy. Holding of retainage or making partial payment to subcontractors for work that was approved and paid by MDOT is to be reported to the Construction Field Services Division.<br />
<br />
{{top}}<br />
<br />
===[[#Questions|Questions]]===<br />
<br />
OBD can be contacted at MDOT-DBE@michigan.gov with any DBE related questions or concerns. Messages can be left at 866-323-1264 or 866-323-4009 and an OBD staff person will respond.<br />
<br />
Please share this information with consultants and local agencies in your area. If you have any questions, please contact Jason Gutting, Engineer of Construction Operations, at [mailto:guttingj@michigan.gov Jason Gutting] or 517-636-6334.<br />
<br />
{{top}}<br />
<br />
===[[#Construction Manual| Construction Manual]]===<br />
<br />
The contents of this BOHIM will be placed and maintained in the MDOT Construction Manual. After incorporation the BOHIM will sunset and link directly to the Construction Manual.<br />
<br />
{{top}}<br />
<br />
[[Category: Construction Manual]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=Disadvantaged_Business_Enterprises_(DBE)&diff=3840Disadvantaged Business Enterprises (DBE)2014-11-03T20:18:54Z<p>HarrisR18: </p>
<hr />
<div>===[[#Equal Employment Opportunity|Equal Employment Opportunity]]===<br />
<br />
MDOT must ensure that all federal-aid contractors, sub-contractors, vendors, and material suppliers do not discriminate in employment and contracting practices based on race, color, religion (in the context of employment), sex, national origin, age, or disability.<br />
<br />
Any deficiencies noted in a contractor’s EEO program are to be provided to the [mailto:MDOT-DBE@michigan.gov MDOT Office of Business Development (OBD)] at 866-323-1264.<br />
<br />
A contractor’s affirmative action plan is to be comprised of the following contractual requirements: EO provisions, training provisions, Federal Highway Administration (FHWA) Form 1273, Title VI (under Appendix C of the project proposal) and Disadvantaged Business Enterprise (DBE) goals and provisions.<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Coordinator|Title VI Coordinator]]=== <br />
<br />
Cheryl Hudson is MDOT’s Title VI Coordinator. She can be contacted at 517-373-0980 or at [mailto:HudsonC1@michigan.gov Cheryl Hudson] for any issues related to civil rights.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Definition|Title VI Definition]]===<br />
<br />
No person in the United States shall, on the grounds of race, color, or national origin, be excluded from participation in, be denied the benefits of, or be otherwise subjected to discrimination under any program or activity funded in whole or in part with federal funds.<br />
<br />
{{top}}<br />
<br />
===[[#Equal Opprotunity (EO) Contract Compliance|Equal Opprotunity (EO) Contract Compliance]]===<br />
<br />
MDOT’s OBD conducts federally-required EO and EEO compliance reviews as part of its monitoring responsibilities. OBD staff determines whether the contractor took all necessary and reasonable steps to comply with these requirements.<br />
<br />
EO requirements in FHWA, Form 1273, Required Contract Provisions Federal-Aid Construction Contracts, apply to all contractors, subcontractors, vendors and suppliers on all federal-aid contracts of $10,000 or more. As specified in FHWA Form 1273, the contractor (or subcontractor) must include this form in each subcontract and further require its inclusion in all lower tier subcontracts (excluding purchase orders, rental agreements and other agreements for supplies or services).<br />
<br />
FHWA Form 1273 is to be physically incorporated in each federal-aid highway construction contract and subcontract. Form 1273 may be bound electronically into an electronic contract/subcontract (PDF format) but may not be left out and only referenced (website location, etc.) as it must be physically included in every contract/subcontract. The construction/project engineer should discuss FHWA Form 1273 at the preconstruction meeting.<br />
<br />
The construction/project engineer must ensure that contractors EO posters are in order and conspicuously placed on the project site as the FHWA requires contractors to prominently display posters in areas available to employees and applicants for employment during the life of the project. The poster display is to include the prime contractor’s EEO policy statement and the name and contact information of the prime’s EEO Officer. All notices and posters are to be legible, protected from the elements, and the dates must be shown. Mobile operations can have the posters located in a vehicle. Complete Form 1967, Jobsite Poster Inspection Checklist, at the start of construction operations and any time the poster display is moved. The form is an aid to make sure that the contractor is following the proper procedure and is to be placed in the project files after completion of the form.<br />
<br />
Job site posters should be discussed at the preconstruction meeting. The required job site posting information can be found under Section C at the following MDOT website: http://www.michigan.gov/mdot/0,4616,7-151-9622_11044_11367-222170--,00.html. <br />
<br />
<br />
If construction staff receives a complaint from the employee of a contractor or subcontractor they are to notify through email [mailto:DBE@michigan.gov OBD] or call at 866-323-1264 (all MDOT Regions except Metro) or 866-323-4009 (Metro Region).<br />
<br />
If construction staff receives a complaint involving an MDOT employee or other persons who are not employees of contractors on a project, they are to contact the MDOT Title VI Coordinator.<br />
<br />
Construction staff is to evaluate any problems or issues encountered with EEO, DBE or Title VI compliance when completing contractor performance evaluations.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#On-The-Job Training|On-The-Job Training]]===<br />
<br />
MDOT’s OJT program is based on requirements of Appendix B to Subpart A of Title 23 Code of Federal Regulations Part 230 (23 CFR Part 230), which requires inclusion of training special provisions in federal-aid construction contracts. The OJT program provides opportunities for unskilled workers to acquire training in skilled construction trades. The primary objective of the OJT program is to train and upgrade minorities, women, and disadvantaged persons toward full journey-level status and to provide opportunities for trainees to become part of a contractor’s permanent workforce. OJT program details are available from MDOT’s OBD or on the web at http://michigan.gov/ojt.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#Disadvantages Business Enterprises (DBE)|Disadvantages Business Enterprises (DBE)]]===<br />
<br />
DBE companies are contractors (prime, sub, sub-sub, etc.), truckers, materials suppliers, consultants and other service providers who are certified as having met requirements of 49 CFR Part 26. A current list of all DBE companies certified to work in Michigan by work classification and work type is available at: http://www.michigan.gov/mucp<br />
<br />
The document titled, 2013 DBE Program Procedures, is MDOT’s federally-approved plan for its DBE program. This document contains detailed information and is available at http://www.michigan.gov/mdotdbe under the Resources link.<br />
<br />
DBE race-conscious (RC) participation goals are expressed as a percentage of work which must be contracted to DBE companies for applicable projects with a DBE goal. On RC projects the prime contractor is required to provide DBE commitment sheets (Form 0178, Disadvantaged Business Enterprise (DBE) Participation) prior to contract award. The construction/project engineer is notified via email (or file presence in ProjectWise) of the prime contractor DBE commitments on RC projects or when there are changes in the goal or DBE companies committed to the project. These notifications are to be provided to construction staff assigned to the project. DBE commitments, subcontracts, and the current DBE goal (when applicable) assigned to a project are posted on MDOT’s Construction Contract Inquiry website at http://mdotcf.state.mi.us/public/trnsport/.<br />
<br />
The following tasks related to DBE oversight are to be completed on all federally funded projects. The task list provides guidance to project construction staff related to their responsibilities for oversight of DBE compliance.<br />
<br />
1.Collect all DBE subcontracts and purchase orders from prime contractor. Provide copies of purchase orders to OBD with the respective 4109 form submittal.<br />
<br />
2.Review DBE commitment sheets (form 0178, also known as blue sheets) for awareness and knowledge.<br />
<br />
3.Monitor and document DBE work operations.<br />
<br />
4.Monitor and document Commercially Useful Function (CUF) compliance (form 4109) during construction operations and provide a copy of form 4109 to OBD as noted on the form.<br />
<br />
5.Monitor compliance with DBE commitments (work type, amounts committed, DBE payments, etc.).<br />
<br />
6.Monitor overall DBE participation percentage as construction work progresses.<br />
<br />
7.Calculate the final overall DBE participation percentage to check for compliance with the contract requirements. Contact OBD with non-compliance issues.<br />
<br />
8.Document all DBE contracting issues, concerns, problems, etc. and provide to OBD for discussion and resolution.<br />
<br />
9.Provide all DBE substitution forms in accordance with form instructions and distribution lists.<br />
<br />
When the construction/project engineer becomes aware that a DBE goal will not be met due to the inability of a DBE to perform work, changes in DBE subcontracting, reduced quantities, changes in the work, etc., the construction/project engineer must direct the contractor to submit a specific plan to address the goal deficiency to the engineer. The construction/project engineer will provide a copy of the submitted plan to OBD.<br />
<br />
The contractor may, after award, request a waiver or modification of the DBE participation goal. The contractor must submit evidence of good faith efforts to meet the DBE participation goal. This includes documentation to support that the amount of contract work remaining was carefully reviewed to identify other work which could be subcontracted to DBE firms.<br />
<br />
If the prime contractor is not meeting its RC DBE participation goal after project award, it must request a post award waiver or modification of the goal. These requests are to be submitted with Form 0188, Contractor Good Faith Effort Application. Requests for waiver or modification of a DBE participation goal must be submitted to OBD immediately upon awareness.<br />
<br />
Contractors are not allowed to arbitrarily reduce the amount of work committed to DBE companies or terminate a DBE subcontractor without construction/project engineer approval, including the self performance of previously committed DBE work. The construction/project engineer is to be notified of a DBE company’s inability to perform work and the contractor’s intent to obtain a substitute DBE on projects with race-conscious (RC) DBE participation goals. A DBE who is unable to perform work must be given five business days written notice by the contractor of their intent to obtain a substitute DBE. The contractor is required to provide copies of the notice to the construction/project engineer and OBD. To substitute DBE companies, the prime contractor must then submit Form 0196, Request to Replace Disadvantaged Business Enterprise. The construction/project engineer must review and approve (in consultation with OBD) any DBE substitutions before submitting the approved form to the MDOT Contract Services Division.<br />
<br />
Work items, if applicable and available, must be properly assigned in FieldManager to the respective DBE company. Construction staff must document work done by all DBE companies, including truckers, suppliers, service providers, and subcontractors. Documentation is to occur on the Inspector Daily Reports (IDR) or the Commercially Useful Function Form 4109 submittal and should include any concerns or problems. All potential field concerns are to be discussed with OBD staff.<br />
<br />
{{top}}<br />
<br />
===[[#DBE Construction Engineers and Technicians|DBE Construction Engineers and Technicians]]===<br />
<br />
MDOT has assigned construction engineers and technicians by region to help DBE companies bidding or working on construction contracts. The DBE Technician list is available at: http://www.michigan.gov/mdotdbe under the contacts heading.<br />
<br />
{{top}}<br />
===[[#Third Party Complaints|Third Party Complaints]]===<br />
<br />
Any person may file a written complaint alleging that a currently certified firm is in violation of DBE regulations. Complaints must be filed with OBD in writing no later than 180 days after the date of an alleged violation. For further information, refer to the DBE Program Procedures as discussed previously.<br />
<br />
{{top}}<br />
===[[#DBE Commercially Useful Function (CUF) Requirements|DBE Commercially Useful Function (CUF) Requirements]]===<br />
<br />
Field direction on this issue can be reviewed with Bureau of Highway Instructional Memorandum, 2013-12, Disadvantaged Business Enterprise (DBE) Commercially Useful Function (CUF) Compliance or any applicable superseding BOHIM.<br />
<br />
{{top}}<br />
<br />
===[[#Joint Checks|Joint Checks]]===<br />
<br />
A joint check is a two party check between a subcontractor, a prime contractor, and a materials supplier. Joint check arrangements must be approved by OBD and the Contract Services Division in advance of use. MDOT Form 0183, Application to Use Joint Checks, is included in project proposals and must be submitted to the OBD for approval at least two weeks in advance of use of any joint checks.<br />
<br />
{{top}}<br />
<br />
===[[#DBE Documentation| DBE Documentation]]===<br />
<br />
The construction/project engineer should compare names of DBE companies and payments listed via submittal of form 2124A with the following items to check for discrepancies or compliance issues:<br />
<br />
*DBE companies listed on MDOT Form 0178, Disadvantaged Business Enterprise (DBE) Participation.<br />
*The types of work listed on forms 0178 or 0182 with the services/work classification listed on form 2124A.<br />
*Project scheduling and anticipated work presence by DBE companies.<br />
*Any reports of non-compliance with prompt payment requirements.<br />
<br />
Construction/Project engineers should question any deductions shown on form 2124A. Contractors are not permitted to hold any type of retainage per MDOT policy. Holding of retainage or making partial payment to subcontractors for work that was approved and paid by MDOT is to be reported to the Construction Field Services Division.<br />
<br />
{{top}}<br />
<br />
===[[#Questions|Questions]]===<br />
<br />
OBD can be contacted at MDOT-DBE@michigan.gov with any DBE related questions or concerns. Messages can be left at 866-323-1264 or 866-323-4009 and an OBD staff person will respond.<br />
<br />
Please share this information with consultants and local agencies in your area. If you have any questions, please contact Jason Gutting, Engineer of Construction Operations, at [mail to:guttingj@michigan.gov Jason Gutting] or 517-636-6334.<br />
<br />
{{top}}<br />
<br />
===[[#Construction Manual| Construction Manual]]===<br />
<br />
The contents of this BOHIM will be placed and maintained in the MDOT Construction Manual. After incorporation the BOHIM will sunset and link directly to the Construction Manual.<br />
<br />
{{top}}<br />
<br />
[[Category: Construction Manual]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=Disadvantaged_Business_Enterprises_(DBE)&diff=3839Disadvantaged Business Enterprises (DBE)2014-11-03T20:15:55Z<p>HarrisR18: /* Disadvantages Business Enterprises (DBE) */</p>
<hr />
<div>===[[#Equal Employment Opportunity|Equal Employment Opportunity]]===<br />
<br />
MDOT must ensure that all federal-aid contractors, sub-contractors, vendors, and material suppliers do not discriminate in employment and contracting practices based on race, color, religion (in the context of employment), sex, national origin, age, or disability.<br />
<br />
Any deficiencies noted in a contractor’s EEO program are to be provided to the [mailto:MDOT-DBE@michigan.gov MDOT Office of Business Development (OBD)] at 866-323-1264.<br />
<br />
A contractor’s affirmative action plan is to be comprised of the following contractual requirements: EO provisions, training provisions, Federal Highway Administration (FHWA) Form 1273, Title VI (under Appendix C of the project proposal) and Disadvantaged Business Enterprise (DBE) goals and provisions.<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Coordinator|Title VI Coordinator]]=== <br />
<br />
Cheryl Hudson is MDOT’s Title VI Coordinator. She can be contacted at 517-373-0980 or at [mailto:HudsonC1@michigan.gov Cheryl Hudson] for any issues related to civil rights.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Definition|Title VI Definition]]===<br />
<br />
No person in the United States shall, on the grounds of race, color, or national origin, be excluded from participation in, be denied the benefits of, or be otherwise subjected to discrimination under any program or activity funded in whole or in part with federal funds.<br />
<br />
{{top}}<br />
<br />
===[[#Equal Opprotunity (EO) Contract Compliance|Equal Opprotunity (EO) Contract Compliance]]===<br />
<br />
MDOT’s OBD conducts federally-required EO and EEO compliance reviews as part of its monitoring responsibilities. OBD staff determines whether the contractor took all necessary and reasonable steps to comply with these requirements.<br />
<br />
EO requirements in FHWA, Form 1273, Required Contract Provisions Federal-Aid Construction Contracts, apply to all contractors, subcontractors, vendors and suppliers on all federal-aid contracts of $10,000 or more. As specified in FHWA Form 1273, the contractor (or subcontractor) must include this form in each subcontract and further require its inclusion in all lower tier subcontracts (excluding purchase orders, rental agreements and other agreements for supplies or services).<br />
<br />
FHWA Form 1273 is to be physically incorporated in each federal-aid highway construction contract and subcontract. Form 1273 may be bound electronically into an electronic contract/subcontract (PDF format) but may not be left out and only referenced (website location, etc.) as it must be physically included in every contract/subcontract. The construction/project engineer should discuss FHWA Form 1273 at the preconstruction meeting.<br />
<br />
The construction/project engineer must ensure that contractors EO posters are in order and conspicuously placed on the project site as the FHWA requires contractors to prominently display posters in areas available to employees and applicants for employment during the life of the project. The poster display is to include the prime contractor’s EEO policy statement and the name and contact information of the prime’s EEO Officer. All notices and posters are to be legible, protected from the elements, and the dates must be shown. Mobile operations can have the posters located in a vehicle. Complete Form 1967, Jobsite Poster Inspection Checklist, at the start of construction operations and any time the poster display is moved. The form is an aid to make sure that the contractor is following the proper procedure and is to be placed in the project files after completion of the form.<br />
<br />
Job site posters should be discussed at the preconstruction meeting. The required job site posting information can be found under Section C at the following MDOT website: http://www.michigan.gov/mdot/0,4616,7-151-9622_11044_11367-222170--,00.html. <br />
<br />
<br />
If construction staff receives a complaint from the employee of a contractor or subcontractor they are to notify through email [mailto:DBE@michigan.gov OBD] or call at 866-323-1264 (all MDOT Regions except Metro) or 866-323-4009 (Metro Region).<br />
<br />
If construction staff receives a complaint involving an MDOT employee or other persons who are not employees of contractors on a project, they are to contact the MDOT Title VI Coordinator.<br />
<br />
Construction staff is to evaluate any problems or issues encountered with EEO, DBE or Title VI compliance when completing contractor performance evaluations.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#On-The-Job Training|On-The-Job Training]]===<br />
<br />
MDOT’s OJT program is based on requirements of Appendix B to Subpart A of Title 23 Code of Federal Regulations Part 230 (23 CFR Part 230), which requires inclusion of training special provisions in federal-aid construction contracts. The OJT program provides opportunities for unskilled workers to acquire training in skilled construction trades. The primary objective of the OJT program is to train and upgrade minorities, women, and disadvantaged persons toward full journey-level status and to provide opportunities for trainees to become part of a contractor’s permanent workforce. OJT program details are available from MDOT’s OBD or on the web at http://michigan.gov/ojt.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#Disadvantages Business Enterprises (DBE)|Disadvantages Business Enterprises (DBE)]]===<br />
<br />
DBE companies are contractors (prime, sub, sub-sub, etc.), truckers, materials suppliers, consultants and other service providers who are certified as having met requirements of 49 CFR Part 26. A current list of all DBE companies certified to work in Michigan by work classification and work type is available at: http://www.michigan.gov/mucp<br />
<br />
The document titled, 2013 DBE Program Procedures, is MDOT’s federally-approved plan for its DBE program. This document contains detailed information and is available at http://www.michigan.gov/mdotdbe under the Resources link.<br />
<br />
DBE race-conscious (RC) participation goals are expressed as a percentage of work which must be contracted to DBE companies for applicable projects with a DBE goal. On RC projects the prime contractor is required to provide DBE commitment sheets (Form 0178, Disadvantaged Business Enterprise (DBE) Participation) prior to contract award. The construction/project engineer is notified via email (or file presence in ProjectWise) of the prime contractor DBE commitments on RC projects or when there are changes in the goal or DBE companies committed to the project. These notifications are to be provided to construction staff assigned to the project. DBE commitments, subcontracts, and the current DBE goal (when applicable) assigned to a project are posted on MDOT’s Construction Contract Inquiry website at http://mdotcf.state.mi.us/public/trnsport/.<br />
<br />
The following tasks related to DBE oversight are to be completed on all federally funded projects. The task list provides guidance to project construction staff related to their responsibilities for oversight of DBE compliance.<br />
<br />
1.Collect all DBE subcontracts and purchase orders from prime contractor. Provide copies of purchase orders to OBD with the respective 4109 form submittal.<br />
<br />
2.Review DBE commitment sheets (form 0178, also known as blue sheets) for awareness and knowledge.<br />
<br />
3.Monitor and document DBE work operations.<br />
<br />
4.Monitor and document Commercially Useful Function (CUF) compliance (form 4109) during construction operations and provide a copy of form 4109 to OBD as noted on the form.<br />
<br />
5.Monitor compliance with DBE commitments (work type, amounts committed, DBE payments, etc.).<br />
<br />
6.Monitor overall DBE participation percentage as construction work progresses.<br />
<br />
7.Calculate the final overall DBE participation percentage to check for compliance with the contract requirements. Contact OBD with non-compliance issues.<br />
<br />
8.Document all DBE contracting issues, concerns, problems, etc. and provide to OBD for discussion and resolution.<br />
<br />
9.Provide all DBE substitution forms in accordance with form instructions and distribution lists.<br />
<br />
When the construction/project engineer becomes aware that a DBE goal will not be met due to the inability of a DBE to perform work, changes in DBE subcontracting, reduced quantities, changes in the work, etc., the construction/project engineer must direct the contractor to submit a specific plan to address the goal deficiency to the engineer. The construction/project engineer will provide a copy of the submitted plan to OBD.<br />
<br />
The contractor may, after award, request a waiver or modification of the DBE participation goal. The contractor must submit evidence of good faith efforts to meet the DBE participation goal. This includes documentation to support that the amount of contract work remaining was carefully reviewed to identify other work which could be subcontracted to DBE firms.<br />
<br />
If the prime contractor is not meeting its RC DBE participation goal after project award, it must request a post award waiver or modification of the goal. These requests are to be submitted with Form 0188, Contractor Good Faith Effort Application. Requests for waiver or modification of a DBE participation goal must be submitted to OBD immediately upon awareness.<br />
<br />
Contractors are not allowed to arbitrarily reduce the amount of work committed to DBE companies or terminate a DBE subcontractor without construction/project engineer approval, including the self performance of previously committed DBE work. The construction/project engineer is to be notified of a DBE company’s inability to perform work and the contractor’s intent to obtain a substitute DBE on projects with race-conscious (RC) DBE participation goals. A DBE who is unable to perform work must be given five business days written notice by the contractor of their intent to obtain a substitute DBE. The contractor is required to provide copies of the notice to the construction/project engineer and OBD. To substitute DBE companies, the prime contractor must then submit Form 0196, Request to Replace Disadvantaged Business Enterprise. The construction/project engineer must review and approve (in consultation with OBD) any DBE substitutions before submitting the approved form to the MDOT Contract Services Division.<br />
<br />
Work items, if applicable and available, must be properly assigned in FieldManager to the respective DBE company. Construction staff must document work done by all DBE companies, including truckers, suppliers, service providers, and subcontractors. Documentation is to occur on the Inspector Daily Reports (IDR) or the Commercially Useful Function Form 4109 submittal and should include any concerns or problems. All potential field concerns are to be discussed with OBD staff.<br />
<br />
{{top}}<br />
<br />
===[[#DBE Construction Engineers and Technicians|DBE Construction Engineers and Technicians]]===<br />
<br />
MDOT has assigned construction engineers and technicians by region to help DBE companies bidding or working on construction contracts. The DBE Technician list is available at: http://www.michigan.gov/mdotdbe under the contacts heading.<br />
<br />
===[[#Third Party Complaints|Third Party Complaints]]===<br />
<br />
Any person may file a written complaint alleging that a currently certified firm is in violation of DBE regulations. Complaints must be filed with OBD in writing no later than 180 days after the date of an alleged violation. For further information, refer to the DBE Program Procedures as discussed previously.<br />
<br />
===[[#DBE Commercially Useful Function (CUF) Requirements|DBE Commercially Useful Function (CUF) Requirements]]===<br />
<br />
Field direction on this issue can be reviewed with Bureau of Highway Instructional Memorandum, 2013-12, Disadvantaged Business Enterprise (DBE) Commercially Useful Function (CUF) Compliance or any applicable superseding BOHIM.<br />
<br />
===[[#Joint Checks|Joint Checks]]===<br />
<br />
A joint check is a two party check between a subcontractor, a prime contractor, and a materials supplier. Joint check arrangements must be approved by OBD and the Contract Services Division in advance of use. MDOT Form 0183, Application to Use Joint Checks, is included in project proposals and must be submitted to the OBD for approval at least two weeks in advance of use of any joint checks.<br />
<br />
===[[#DBE Documentation| DBE Documentation]]===<br />
<br />
The construction/project engineer should compare names of DBE companies and payments listed via submittal of form 2124A with the following items to check for discrepancies or compliance issues:<br />
<br />
*DBE companies listed on MDOT Form 0178, Disadvantaged Business Enterprise (DBE) Participation.<br />
*The types of work listed on forms 0178 or 0182 with the services/work classification listed on form 2124A.<br />
*Project scheduling and anticipated work presence by DBE companies.<br />
*Any reports of non-compliance with prompt payment requirements.<br />
<br />
Construction/Project engineers should question any deductions shown on form 2124A. Contractors are not permitted to hold any type of retainage per MDOT policy. Holding of retainage or making partial payment to subcontractors for work that was approved and paid by MDOT is to be reported to the Construction Field Services Division.<br />
<br />
===[[#Questions|Questions]]===<br />
<br />
OBD can be contacted at MDOT-DBE@michigan.gov with any DBE related questions or concerns. Messages can be left at 866-323-1264 or 866-323-4009 and an OBD staff person will respond.<br />
<br />
Please share this information with consultants and local agencies in your area. If you have any questions, please contact Jason Gutting, Engineer of Construction Operations, at guttingj@michigan.gov or 517-636-6334.<br />
<br />
<br />
===[[#Construction Manual| Construction Manual]]===<br />
<br />
The contents of this BOHIM will be placed and maintained in the MDOT Construction Manual. After incorporation the BOHIM will sunset and link directly to the Construction Manual.<br />
<br />
<br />
[[Category: Construction Manual]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=Disadvantaged_Business_Enterprises_(DBE)&diff=3838Disadvantaged Business Enterprises (DBE)2014-11-03T20:15:05Z<p>HarrisR18: /* On-The-Job Training */</p>
<hr />
<div>===[[#Equal Employment Opportunity|Equal Employment Opportunity]]===<br />
<br />
MDOT must ensure that all federal-aid contractors, sub-contractors, vendors, and material suppliers do not discriminate in employment and contracting practices based on race, color, religion (in the context of employment), sex, national origin, age, or disability.<br />
<br />
Any deficiencies noted in a contractor’s EEO program are to be provided to the [mailto:MDOT-DBE@michigan.gov MDOT Office of Business Development (OBD)] at 866-323-1264.<br />
<br />
A contractor’s affirmative action plan is to be comprised of the following contractual requirements: EO provisions, training provisions, Federal Highway Administration (FHWA) Form 1273, Title VI (under Appendix C of the project proposal) and Disadvantaged Business Enterprise (DBE) goals and provisions.<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Coordinator|Title VI Coordinator]]=== <br />
<br />
Cheryl Hudson is MDOT’s Title VI Coordinator. She can be contacted at 517-373-0980 or at [mailto:HudsonC1@michigan.gov Cheryl Hudson] for any issues related to civil rights.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Definition|Title VI Definition]]===<br />
<br />
No person in the United States shall, on the grounds of race, color, or national origin, be excluded from participation in, be denied the benefits of, or be otherwise subjected to discrimination under any program or activity funded in whole or in part with federal funds.<br />
<br />
{{top}}<br />
<br />
===[[#Equal Opprotunity (EO) Contract Compliance|Equal Opprotunity (EO) Contract Compliance]]===<br />
<br />
MDOT’s OBD conducts federally-required EO and EEO compliance reviews as part of its monitoring responsibilities. OBD staff determines whether the contractor took all necessary and reasonable steps to comply with these requirements.<br />
<br />
EO requirements in FHWA, Form 1273, Required Contract Provisions Federal-Aid Construction Contracts, apply to all contractors, subcontractors, vendors and suppliers on all federal-aid contracts of $10,000 or more. As specified in FHWA Form 1273, the contractor (or subcontractor) must include this form in each subcontract and further require its inclusion in all lower tier subcontracts (excluding purchase orders, rental agreements and other agreements for supplies or services).<br />
<br />
FHWA Form 1273 is to be physically incorporated in each federal-aid highway construction contract and subcontract. Form 1273 may be bound electronically into an electronic contract/subcontract (PDF format) but may not be left out and only referenced (website location, etc.) as it must be physically included in every contract/subcontract. The construction/project engineer should discuss FHWA Form 1273 at the preconstruction meeting.<br />
<br />
The construction/project engineer must ensure that contractors EO posters are in order and conspicuously placed on the project site as the FHWA requires contractors to prominently display posters in areas available to employees and applicants for employment during the life of the project. The poster display is to include the prime contractor’s EEO policy statement and the name and contact information of the prime’s EEO Officer. All notices and posters are to be legible, protected from the elements, and the dates must be shown. Mobile operations can have the posters located in a vehicle. Complete Form 1967, Jobsite Poster Inspection Checklist, at the start of construction operations and any time the poster display is moved. The form is an aid to make sure that the contractor is following the proper procedure and is to be placed in the project files after completion of the form.<br />
<br />
Job site posters should be discussed at the preconstruction meeting. The required job site posting information can be found under Section C at the following MDOT website: http://www.michigan.gov/mdot/0,4616,7-151-9622_11044_11367-222170--,00.html. <br />
<br />
<br />
If construction staff receives a complaint from the employee of a contractor or subcontractor they are to notify through email [mailto:DBE@michigan.gov OBD] or call at 866-323-1264 (all MDOT Regions except Metro) or 866-323-4009 (Metro Region).<br />
<br />
If construction staff receives a complaint involving an MDOT employee or other persons who are not employees of contractors on a project, they are to contact the MDOT Title VI Coordinator.<br />
<br />
Construction staff is to evaluate any problems or issues encountered with EEO, DBE or Title VI compliance when completing contractor performance evaluations.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#On-The-Job Training|On-The-Job Training]]===<br />
<br />
MDOT’s OJT program is based on requirements of Appendix B to Subpart A of Title 23 Code of Federal Regulations Part 230 (23 CFR Part 230), which requires inclusion of training special provisions in federal-aid construction contracts. The OJT program provides opportunities for unskilled workers to acquire training in skilled construction trades. The primary objective of the OJT program is to train and upgrade minorities, women, and disadvantaged persons toward full journey-level status and to provide opportunities for trainees to become part of a contractor’s permanent workforce. OJT program details are available from MDOT’s OBD or on the web at http://michigan.gov/ojt.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#Disadvantages Business Enterprises (DBE)|Disadvantages Business Enterprises (DBE)]]===<br />
<br />
DBE companies are contractors (prime, sub, sub-sub, etc.), truckers, materials suppliers, consultants and other service providers who are certified as having met requirements of 49 CFR Part 26. A current list of all DBE companies certified to work in Michigan by work classification and work type is available at: http://www.michigan.gov/mucp<br />
<br />
The document titled, 2013 DBE Program Procedures, is MDOT’s federally-approved plan for its DBE program. This document contains detailed information and is available at http://www.michigan.gov/mdotdbe under the Resources link.<br />
<br />
DBE race-conscious (RC) participation goals are expressed as a percentage of work which must be contracted to DBE companies for applicable projects with a DBE goal. On RC projects the prime contractor is required to provide DBE commitment sheets (Form 0178, Disadvantaged Business Enterprise (DBE) Participation) prior to contract award. The construction/project engineer is notified via email (or file presence in ProjectWise) of the prime contractor DBE commitments on RC projects or when there are changes in the goal or DBE companies committed to the project. These notifications are to be provided to construction staff assigned to the project. DBE commitments, subcontracts, and the current DBE goal (when applicable) assigned to a project are posted on MDOT’s Construction Contract Inquiry website at http://mdotcf.state.mi.us/public/trnsport/.<br />
<br />
The following tasks related to DBE oversight are to be completed on all federally funded projects. The task list provides guidance to project construction staff related to their responsibilities for oversight of DBE compliance.<br />
<br />
1.Collect all DBE subcontracts and purchase orders from prime contractor. Provide copies of purchase orders to OBD with the respective 4109 form submittal.<br />
2.Review DBE commitment sheets (form 0178, also known as blue sheets) for awareness and knowledge.<br />
3.Monitor and document DBE work operations.<br />
4.Monitor and document Commercially Useful Function (CUF) compliance (form 4109) during construction operations and provide a copy of form 4109 to OBD as noted on the form.<br />
5.Monitor compliance with DBE commitments (work type, amounts committed, DBE payments, etc.).<br />
6.Monitor overall DBE participation percentage as construction work progresses.<br />
7.Calculate the final overall DBE participation percentage to check for compliance with the contract requirements. Contact OBD with non-compliance issues.<br />
8.Document all DBE contracting issues, concerns, problems, etc. and provide to OBD for discussion and resolution.<br />
9.Provide all DBE substitution forms in accordance with form instructions and distribution lists.<br />
<br />
When the construction/project engineer becomes aware that a DBE goal will not be met due to the inability of a DBE to perform work, changes in DBE subcontracting, reduced quantities, changes in the work, etc., the construction/project engineer must direct the contractor to submit a specific plan to address the goal deficiency to the engineer. The construction/project engineer will provide a copy of the submitted plan to OBD.<br />
<br />
The contractor may, after award, request a waiver or modification of the DBE participation goal. The contractor must submit evidence of good faith efforts to meet the DBE participation goal. This includes documentation to support that the amount of contract work remaining was carefully reviewed to identify other work which could be subcontracted to DBE firms.<br />
<br />
If the prime contractor is not meeting its RC DBE participation goal after project award, it must request a post award waiver or modification of the goal. These requests are to be submitted with Form 0188, Contractor Good Faith Effort Application. Requests for waiver or modification of a DBE participation goal must be submitted to OBD immediately upon awareness.<br />
<br />
Contractors are not allowed to arbitrarily reduce the amount of work committed to DBE companies or terminate a DBE subcontractor without construction/project engineer approval, including the self performance of previously committed DBE work. The construction/project engineer is to be notified of a DBE company’s inability to perform work and the contractor’s intent to obtain a substitute DBE on projects with race-conscious (RC) DBE participation goals. A DBE who is unable to perform work must be given five business days written notice by the contractor of their intent to obtain a substitute DBE. The contractor is required to provide copies of the notice to the construction/project engineer and OBD. To substitute DBE companies, the prime contractor must then submit Form 0196, Request to Replace Disadvantaged Business Enterprise. The construction/project engineer must review and approve (in consultation with OBD) any DBE substitutions before submitting the approved form to the MDOT Contract Services Division.<br />
<br />
Work items, if applicable and available, must be properly assigned in FieldManager to the respective DBE company. Construction staff must document work done by all DBE companies, including truckers, suppliers, service providers, and subcontractors. Documentation is to occur on the Inspector Daily Reports (IDR) or the Commercially Useful Function Form 4109 submittal and should include any concerns or problems. All potential field concerns are to be discussed with OBD staff. <br />
<br />
<br />
===[[#DBE Construction Engineers and Technicians|DBE Construction Engineers and Technicians]]===<br />
<br />
MDOT has assigned construction engineers and technicians by region to help DBE companies bidding or working on construction contracts. The DBE Technician list is available at: http://www.michigan.gov/mdotdbe under the contacts heading.<br />
<br />
===[[#Third Party Complaints|Third Party Complaints]]===<br />
<br />
Any person may file a written complaint alleging that a currently certified firm is in violation of DBE regulations. Complaints must be filed with OBD in writing no later than 180 days after the date of an alleged violation. For further information, refer to the DBE Program Procedures as discussed previously.<br />
<br />
===[[#DBE Commercially Useful Function (CUF) Requirements|DBE Commercially Useful Function (CUF) Requirements]]===<br />
<br />
Field direction on this issue can be reviewed with Bureau of Highway Instructional Memorandum, 2013-12, Disadvantaged Business Enterprise (DBE) Commercially Useful Function (CUF) Compliance or any applicable superseding BOHIM.<br />
<br />
===[[#Joint Checks|Joint Checks]]===<br />
<br />
A joint check is a two party check between a subcontractor, a prime contractor, and a materials supplier. Joint check arrangements must be approved by OBD and the Contract Services Division in advance of use. MDOT Form 0183, Application to Use Joint Checks, is included in project proposals and must be submitted to the OBD for approval at least two weeks in advance of use of any joint checks.<br />
<br />
===[[#DBE Documentation| DBE Documentation]]===<br />
<br />
The construction/project engineer should compare names of DBE companies and payments listed via submittal of form 2124A with the following items to check for discrepancies or compliance issues:<br />
<br />
*DBE companies listed on MDOT Form 0178, Disadvantaged Business Enterprise (DBE) Participation.<br />
*The types of work listed on forms 0178 or 0182 with the services/work classification listed on form 2124A.<br />
*Project scheduling and anticipated work presence by DBE companies.<br />
*Any reports of non-compliance with prompt payment requirements.<br />
<br />
Construction/Project engineers should question any deductions shown on form 2124A. Contractors are not permitted to hold any type of retainage per MDOT policy. Holding of retainage or making partial payment to subcontractors for work that was approved and paid by MDOT is to be reported to the Construction Field Services Division.<br />
<br />
===[[#Questions|Questions]]===<br />
<br />
OBD can be contacted at MDOT-DBE@michigan.gov with any DBE related questions or concerns. Messages can be left at 866-323-1264 or 866-323-4009 and an OBD staff person will respond.<br />
<br />
Please share this information with consultants and local agencies in your area. If you have any questions, please contact Jason Gutting, Engineer of Construction Operations, at guttingj@michigan.gov or 517-636-6334.<br />
<br />
<br />
===[[#Construction Manual| Construction Manual]]===<br />
<br />
The contents of this BOHIM will be placed and maintained in the MDOT Construction Manual. After incorporation the BOHIM will sunset and link directly to the Construction Manual.<br />
<br />
<br />
[[Category: Construction Manual]]</div>HarrisR18https://mdotwiki.state.mi.us/construction/index.php?title=Disadvantaged_Business_Enterprises_(DBE)&diff=3837Disadvantaged Business Enterprises (DBE)2014-11-03T20:14:11Z<p>HarrisR18: /* Equal Opprotunity (EO) Contract Compliance */</p>
<hr />
<div>===[[#Equal Employment Opportunity|Equal Employment Opportunity]]===<br />
<br />
MDOT must ensure that all federal-aid contractors, sub-contractors, vendors, and material suppliers do not discriminate in employment and contracting practices based on race, color, religion (in the context of employment), sex, national origin, age, or disability.<br />
<br />
Any deficiencies noted in a contractor’s EEO program are to be provided to the [mailto:MDOT-DBE@michigan.gov MDOT Office of Business Development (OBD)] at 866-323-1264.<br />
<br />
A contractor’s affirmative action plan is to be comprised of the following contractual requirements: EO provisions, training provisions, Federal Highway Administration (FHWA) Form 1273, Title VI (under Appendix C of the project proposal) and Disadvantaged Business Enterprise (DBE) goals and provisions.<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Coordinator|Title VI Coordinator]]=== <br />
<br />
Cheryl Hudson is MDOT’s Title VI Coordinator. She can be contacted at 517-373-0980 or at [mailto:HudsonC1@michigan.gov Cheryl Hudson] for any issues related to civil rights.<br />
<br />
<br />
{{top}}<br />
<br />
===[[#Title VI Definition|Title VI Definition]]===<br />
<br />
No person in the United States shall, on the grounds of race, color, or national origin, be excluded from participation in, be denied the benefits of, or be otherwise subjected to discrimination under any program or activity funded in whole or in part with federal funds.<br />
<br />
{{top}}<br />
<br />
===[[#Equal Opprotunity (EO) Contract Compliance|Equal Opprotunity (EO) Contract Compliance]]===<br />
<br />
MDOT’s OBD conducts federally-required EO and EEO compliance reviews as part of its monitoring responsibilities. OBD staff determines whether the contractor took all necessary and reasonable steps to comply with these requirements.<br />
<br />
EO requirements in FHWA, Form 1273, Required Contract Provisions Federal-Aid Construction Contracts, apply to all contractors, subcontractors, vendors and suppliers on all federal-aid contracts of $10,000 or more. As specified in FHWA Form 1273, the contractor (or subcontractor) must include this form in each subcontract and further require its inclusion in all lower tier subcontracts (excluding purchase orders, rental agreements and other agreements for supplies or services).<br />
<br />
FHWA Form 1273 is to be physically incorporated in each federal-aid highway construction contract and subcontract. Form 1273 may be bound electronically into an electronic contract/subcontract (PDF format) but may not be left out and only referenced (website location, etc.) as it must be physically included in every contract/subcontract. The construction/project engineer should discuss FHWA Form 1273 at the preconstruction meeting.<br />
<br />
The construction/project engineer must ensure that contractors EO posters are in order and conspicuously placed on the project site as the FHWA requires contractors to prominently display posters in areas available to employees and applicants for employment during the life of the project. The poster display is to include the prime contractor’s EEO policy statement and the name and contact information of the prime’s EEO Officer. All notices and posters are to be legible, protected from the elements, and the dates must be shown. Mobile operations can have the posters located in a vehicle. Complete Form 1967, Jobsite Poster Inspection Checklist, at the start of construction operations and any time the poster display is moved. The form is an aid to make sure that the contractor is following the proper procedure and is to be placed in the project files after completion of the form.<br />
<br />
Job site posters should be discussed at the preconstruction meeting. The required job site posting information can be found under Section C at the following MDOT website: http://www.michigan.gov/mdot/0,4616,7-151-9622_11044_11367-222170--,00.html. <br />
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If construction staff receives a complaint from the employee of a contractor or subcontractor they are to notify through email [mailto:DBE@michigan.gov OBD] or call at 866-323-1264 (all MDOT Regions except Metro) or 866-323-4009 (Metro Region).<br />
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If construction staff receives a complaint involving an MDOT employee or other persons who are not employees of contractors on a project, they are to contact the MDOT Title VI Coordinator.<br />
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Construction staff is to evaluate any problems or issues encountered with EEO, DBE or Title VI compliance when completing contractor performance evaluations.<br />
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===[[#On-The-Job Training|On-The-Job Training]]===<br />
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MDOT’s OJT program is based on requirements of Appendix B to Subpart A of Title 23 Code of Federal Regulations Part 230 (23 CFR Part 230), which requires inclusion of training special provisions in federal-aid construction contracts. The OJT program provides opportunities for unskilled workers to acquire training in skilled construction trades. The primary objective of the OJT program is to train and upgrade minorities, women, and disadvantaged persons toward full journey-level status and to provide opportunities for trainees to become part of a contractor’s permanent workforce. OJT program details are available from MDOT’s OBD or on the web at http://michigan.gov/ojt.<br />
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===[[#Disadvantages Business Enterprises (DBE)|Disadvantages Business Enterprises (DBE)]]===<br />
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DBE companies are contractors (prime, sub, sub-sub, etc.), truckers, materials suppliers, consultants and other service providers who are certified as having met requirements of 49 CFR Part 26. A current list of all DBE companies certified to work in Michigan by work classification and work type is available at: http://www.michigan.gov/mucp<br />
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The document titled, 2013 DBE Program Procedures, is MDOT’s federally-approved plan for its DBE program. This document contains detailed information and is available at http://www.michigan.gov/mdotdbe under the Resources link.<br />
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DBE race-conscious (RC) participation goals are expressed as a percentage of work which must be contracted to DBE companies for applicable projects with a DBE goal. On RC projects the prime contractor is required to provide DBE commitment sheets (Form 0178, Disadvantaged Business Enterprise (DBE) Participation) prior to contract award. The construction/project engineer is notified via email (or file presence in ProjectWise) of the prime contractor DBE commitments on RC projects or when there are changes in the goal or DBE companies committed to the project. These notifications are to be provided to construction staff assigned to the project. DBE commitments, subcontracts, and the current DBE goal (when applicable) assigned to a project are posted on MDOT’s Construction Contract Inquiry website at http://mdotcf.state.mi.us/public/trnsport/.<br />
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The following tasks related to DBE oversight are to be completed on all federally funded projects. The task list provides guidance to project construction staff related to their responsibilities for oversight of DBE compliance.<br />
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1.Collect all DBE subcontracts and purchase orders from prime contractor. Provide copies of purchase orders to OBD with the respective 4109 form submittal.<br />
2.Review DBE commitment sheets (form 0178, also known as blue sheets) for awareness and knowledge.<br />
3.Monitor and document DBE work operations.<br />
4.Monitor and document Commercially Useful Function (CUF) compliance (form 4109) during construction operations and provide a copy of form 4109 to OBD as noted on the form.<br />
5.Monitor compliance with DBE commitments (work type, amounts committed, DBE payments, etc.).<br />
6.Monitor overall DBE participation percentage as construction work progresses.<br />
7.Calculate the final overall DBE participation percentage to check for compliance with the contract requirements. Contact OBD with non-compliance issues.<br />
8.Document all DBE contracting issues, concerns, problems, etc. and provide to OBD for discussion and resolution.<br />
9.Provide all DBE substitution forms in accordance with form instructions and distribution lists.<br />
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When the construction/project engineer becomes aware that a DBE goal will not be met due to the inability of a DBE to perform work, changes in DBE subcontracting, reduced quantities, changes in the work, etc., the construction/project engineer must direct the contractor to submit a specific plan to address the goal deficiency to the engineer. The construction/project engineer will provide a copy of the submitted plan to OBD.<br />
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The contractor may, after award, request a waiver or modification of the DBE participation goal. The contractor must submit evidence of good faith efforts to meet the DBE participation goal. This includes documentation to support that the amount of contract work remaining was carefully reviewed to identify other work which could be subcontracted to DBE firms.<br />
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If the prime contractor is not meeting its RC DBE participation goal after project award, it must request a post award waiver or modification of the goal. These requests are to be submitted with Form 0188, Contractor Good Faith Effort Application. Requests for waiver or modification of a DBE participation goal must be submitted to OBD immediately upon awareness.<br />
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Contractors are not allowed to arbitrarily reduce the amount of work committed to DBE companies or terminate a DBE subcontractor without construction/project engineer approval, including the self performance of previously committed DBE work. The construction/project engineer is to be notified of a DBE company’s inability to perform work and the contractor’s intent to obtain a substitute DBE on projects with race-conscious (RC) DBE participation goals. A DBE who is unable to perform work must be given five business days written notice by the contractor of their intent to obtain a substitute DBE. The contractor is required to provide copies of the notice to the construction/project engineer and OBD. To substitute DBE companies, the prime contractor must then submit Form 0196, Request to Replace Disadvantaged Business Enterprise. The construction/project engineer must review and approve (in consultation with OBD) any DBE substitutions before submitting the approved form to the MDOT Contract Services Division.<br />
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Work items, if applicable and available, must be properly assigned in FieldManager to the respective DBE company. Construction staff must document work done by all DBE companies, including truckers, suppliers, service providers, and subcontractors. Documentation is to occur on the Inspector Daily Reports (IDR) or the Commercially Useful Function Form 4109 submittal and should include any concerns or problems. All potential field concerns are to be discussed with OBD staff. <br />
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===[[#DBE Construction Engineers and Technicians|DBE Construction Engineers and Technicians]]===<br />
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MDOT has assigned construction engineers and technicians by region to help DBE companies bidding or working on construction contracts. The DBE Technician list is available at: http://www.michigan.gov/mdotdbe under the contacts heading.<br />
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===[[#Third Party Complaints|Third Party Complaints]]===<br />
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Any person may file a written complaint alleging that a currently certified firm is in violation of DBE regulations. Complaints must be filed with OBD in writing no later than 180 days after the date of an alleged violation. For further information, refer to the DBE Program Procedures as discussed previously.<br />
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===[[#DBE Commercially Useful Function (CUF) Requirements|DBE Commercially Useful Function (CUF) Requirements]]===<br />
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Field direction on this issue can be reviewed with Bureau of Highway Instructional Memorandum, 2013-12, Disadvantaged Business Enterprise (DBE) Commercially Useful Function (CUF) Compliance or any applicable superseding BOHIM.<br />
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===[[#Joint Checks|Joint Checks]]===<br />
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A joint check is a two party check between a subcontractor, a prime contractor, and a materials supplier. Joint check arrangements must be approved by OBD and the Contract Services Division in advance of use. MDOT Form 0183, Application to Use Joint Checks, is included in project proposals and must be submitted to the OBD for approval at least two weeks in advance of use of any joint checks.<br />
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===[[#DBE Documentation| DBE Documentation]]===<br />
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The construction/project engineer should compare names of DBE companies and payments listed via submittal of form 2124A with the following items to check for discrepancies or compliance issues:<br />
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*DBE companies listed on MDOT Form 0178, Disadvantaged Business Enterprise (DBE) Participation.<br />
*The types of work listed on forms 0178 or 0182 with the services/work classification listed on form 2124A.<br />
*Project scheduling and anticipated work presence by DBE companies.<br />
*Any reports of non-compliance with prompt payment requirements.<br />
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Construction/Project engineers should question any deductions shown on form 2124A. Contractors are not permitted to hold any type of retainage per MDOT policy. Holding of retainage or making partial payment to subcontractors for work that was approved and paid by MDOT is to be reported to the Construction Field Services Division.<br />
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===[[#Questions|Questions]]===<br />
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OBD can be contacted at MDOT-DBE@michigan.gov with any DBE related questions or concerns. Messages can be left at 866-323-1264 or 866-323-4009 and an OBD staff person will respond.<br />
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Please share this information with consultants and local agencies in your area. If you have any questions, please contact Jason Gutting, Engineer of Construction Operations, at guttingj@michigan.gov or 517-636-6334.<br />
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===[[#Construction Manual| Construction Manual]]===<br />
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The contents of this BOHIM will be placed and maintained in the MDOT Construction Manual. After incorporation the BOHIM will sunset and link directly to the Construction Manual.<br />
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[[Category: Construction Manual]]</div>HarrisR18