807 - Guardrail, Guardrail Terminals, and Miscellaneous Posts

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Guardrail, Guardrail Terminals, and Miscellaneous Posts


The Standard Plans R-56 through R-73 Series include details on guardrail layouts and dimensions. Review the proposal and plans for additional details, notes or special provisions. The designer should provide a completed Guardrail Worksheet, for use as a reference. Attention should be given to subsection 807.03 of the Standard Specifications for Construction regarding completion of guardrail installations within specified time limits and treatment of incomplete guardrail endings.

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Guardrail elements, end sections and posts may be accepted based on a supplier’s certification. Refer to the Materials Source Guide for approved certifiers and product marking requirements.

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Line and Grade

Staking for line and grade is the responsibility of the Contractor. Staking of embankments is the responsibility of the Engineer. The Contractor will mark the locations of the guardrail endings, with verification by the Engineer. Any changes to the design plans, installation instructions or hardware should be discussed by the Contractor, Engineer and designer.

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Guardrail Posts

Posts may be driven or placed in augured holes. When augered holes are used, they are to be backfilled with sound earth and thoroughly tamped in 12 inches (300 mm) layers. Care should be taken in driving posts so that they are properly placed and plumb. Incorrect spacing may not be corrected by increasing the rail slot in the field.

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The use of string line is recommended to establish proper line and grade. Vertical tolerances of 5.8 inch (15 mm) measured off a compacted surface or 1-1/4 inch (30 mm) measured off an earth surface are acceptable. Horizontal tolerances should not exceed 3/4 inch (20 mm) for a 100 foot (30 m) segment when measured using a string line held along the face of a rail section. Rail should be hung so that the rail elements overlap in the direction of traffic. For a guardrail with a radius of 165 to 1000 feet (50 to 300 m), all splice bolts must be tightened before attaching the rail to the posts to prevent buckling at the splice. After a run of guardrail is hung, a visual inspection and adjustments should be made to ensure that the top of the rail presents a smooth line.

Rail should be hung so that the rail elements overlap in the anticipated direction of permanent traffic. Guardrail beam element re-lapping is not mandatory due to temporary traffic shifts or other temporary traffic conditions, regardless of the duration of temporary traffic conditions. However, guardrail re-lapping may be done if deemed feasible and beneficial on a site-by-site, case-by-case basis. Factors such as project duration, condition of existing guardrail hardware, and costs associated with guardrail re-lapping should be considered before planning to re-lap guardrail beam elements on a temporary basis.

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Guardrail Terminals

Guardrail endings will be identified as Guardrail Approach Terminal, Type ___, Guardrail Departing Terminal, Type ___ or Guardrail Anchorage, Bridge, Detail. The pay items will be generic and based on usage (approach/departing, flared/non-flared, double sided, etc.). Several optional designs may be available for each of these types of terminal. The plans and proposal must be reviewed to identify all approved optional designs. Most of the guardrails in use are engineered and patented devices and must be installed according to the manufacturer’s instructions.

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Miscellaneous Posts

Guard posts and mailbox posts will be either driven or placed in augered holes. Existing mailboxes will be attached to the new posts. Existing newspaper boxes and supports that interfere with construction will be removed and stored for property owners’ future installation.

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The guardrail will be measured in feet (meters), in place, along its face. Guardrail terminals and miscellaneous posts are separate pay items and are measured and paid for individually. Refer to Section 807 of the Standard Specifications for Construction for more detail.

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