808 - Fencing

808 Fencing 2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 808

GENERAL

Current policy requires all limited access expressways to be fenced along the ROW. Other locations, such as rural, two-lane roads and selected urban areas, may also require fencing. The fence should ordinarily be 12 inches (300 mm) inside the ROW line.

There are four main types of fencing: woven wire fence, chain link, temporary fence and protective fences. A high-tensile wire fence may occasionally be called for on the plans. The plans will usually designate which type is to be used. Occasionally, barbed wire above the fence will be called for as a deterrent to pedestrians climbing over the fence.

In urban areas, some ROW agreements may include special types of fencing to replace existing fence or to screen property. Whenever existing fencing is removed, review the plans and proposal to ensure that temporary fencing is not required. Major concerns for the inspector are that the fence is not on private property and that the minimum post penetration is achieved.

MATERIALS

Unless otherwise noted, posts and fence fabric will be accepted at the job site if they are accompanied by proper certification. Certification verification testing will be done by MDOT from on-the-job samples, or samples from the Contractor’s yard, to verify the supplier’s certification.

Woven Wire Fence

Woven wire fence is an ordinary farm fence with a thicker galvanized coating and is used predominantly in rural areas. Either wood or steel posts will be used as called for on the plans. However, the Contractor may substitute wood posts for steel posts at no additional cost, if approved by the Engineer.

Chain Link Fence

Chain link fence is a much heavier and closer woven fence than woven wire. Its mesh size is approximately 2 inches (50 mm) diamond-shaped. Chain link fencing is used on most urban expressways. Chain link fence fabric is specified as either hot-dipped galvanized, or aluminum coated. In certain applications, the plans may specify polyvinyl chloride (PVC) color-coated fencing. Applications that specify PVC coated fencing are, generally, limited to urban areas where aesthetics are a concern.

Concrete used to secure chain link fence posts will be Grade P2 or better; however, a concrete report need not be submitted. Chain link fabric and tension wire will be sampled at the job site and tested by the department according to the Standard Specifications for Construction.

The fabric may also be accepted at the job site without sampling provided it has been previously tested and is tagged approved as “Tested Stock”.

Temporary Fence

Temporary fencing is similar to permanent fencing described above; however, it may be either new or used material in good condition. In addition, the installation requirements specified in the Standard Specifications for Construction for setting posts and installing fabric are not as restrictive as those for permanent fencing.

Protective Fence

Protective fencing is used around excavations for bridges or pump stations and in other areas of the project where required for public safety. The fabric is orange-colored polyethylene mesh, with 2 inch (50 mm) diamond-shaped openings, and is 4 feet (1.2 m) in height. Installation, maintenance and removal requirements are specified in the Standard Specifications for Construction.

CONSTRUCTION

When erecting woven wire fence, a line post must be placed every 15 feet (5 meters). Every end, corner, gate, angle, intersection or intermediate post must be braced, as specified in the Standard Specifications for Construction and shown on the Standard Plans. Any section over 660 feet (200 m) in length must have an intermediate post with bracing. Each horizontal strand of wire will be wrapped completely around the end, corner, gate, intermediate brace or angle post and fastened by winding the end around the wire leading up to the post. These wires will then be securely fastened to each post using either wire clamps or staples, depending on the type of post.

Line posts for chain link fence will be spaced at 10 foot (3 m) intervals. All end, corner, gate, angle (over 10 degrees deflection), intersection and intermediate (every 660 feet (200 m) maximum) post will be braced, as specified in the Standard Specifications for Construction and shown on the Standard Plans. All posts for chain link fence will be cast in concrete. When barbed wire is specified, posts will have an extension arm for hanging barbed wire. Width and location of gates will be shown on the plans.

MEASUREMENT AND PAYMENT

Woven wire fence of the type designated will be paid in feet (meters) and will include the posts.

Chain link fence of the height specified will be measured in feet (meters). Gates of the width specified will be paid for as “each”. Payment for posts and concrete is included in the cost of the fence.

When barbed wire is required, it is measured and paid for separately, except when it is part of the Fence, ___ inch, Chain Link, with ___ Strand of Barbed Wire.