641.1 General Description
This work includes furnishing and erecting guardrail and appurtenances according to the specifications. Conform with the lines, grades, and locations shown on the plans or as directed. Place W-beam, T-beam, or “T” beam with modified offset block as shown on the plans and in the Proposal. Unless designated otherwise, references to guardrail shall mean W-beam. Unless provided for in the plans, this work also includes: • Grading to provide the “T” distance shown on the standard behind the guardrail • Grading to construct shoulder flares for approved guardrail anchorage systems and widened shoulders along Guardrail runs according to Section 205 and Section 208 • Furnishing and setting additional posts (all lengths) together with the necessary offset blocks and hardware (when specified in the plans or in the proposal)
641.1.01 Definitions
General Provisions 101 through 150.
641.1.02 Related References
A. Standard Specifications Section 205—Roadway Excavation Section 208—Embankments Section 600 – Controlled Low Strength Flowable Fill Section 645—Repair of Galvanized Coatings Section 700—Grassing Section 859—Guardrail Components Section 870—Paint B. Referenced Documents General Provisions 101 through 150. QPL-64 National Cooperative Highway Research Program (NCHRP) Report 350 American Association of State Highway and Transportation Officials (AASHTO) Manual of Assessing Safety Hardware (MASH)
641.1.03 Submittals
General Provisions 101 through 150.
641.2 Materials
A. Steel Guardrail Use steel Guardrail and steel posts unless specified otherwise on the plans or in the proposal. B. Guardrail Auxiliary Items Ensure that the guardrail includes auxiliary materials and Work to make connections and other guardrail or structures required to complete the construction indicated on the plans. C. Offset Blocks Except at locations approved by the Engineer, use plastic offset blocks according to Subsection 859.2.05 Plastic Offset Blocks for “W” beam guardrail installation. Offset blocks for “T” beam guardrail installations shall be plastic, or modified steel offset blocks per the Standard Plans including Construction Details and Section 859. When approved by the Engineer, use treated wood offset blocks according to Subsection 859.2.04, Wood Guardrail Posts and Offset Blocks only in isolated areas of “W” beam or “T” beam guardrail installations, where standard size blocks would not provide a satisfactory fit. Wood offset blocks and/or wood posts may be specified within the limits of an approved guardrail terminal. Use only one type of offset block within continuous runs of guardrail except in transitions or where specified in the plan details. Ensure that materials meet the requirements of these specifications: Material Section Guardrail Elements and Fittings 859.2.01 Cable End Anchor Assembly 859.2.02 Steel Post and Offset Blocks 859.2.03 Wood Post and Offset Blocks 859.2.04 Plastic Offset Blocks 859.2.05 Galvanized Repair Compound 870.2.05
641.2.01 Delivery, Storage, and Handling
General Provisions 101 through 150.
641.3 Construction Requirements
641.3.01 Personnel
General Provisions 101 through 150.
641.3.02 Equipment
General Provisions 101 through 150.
641.3.03 Preparation
General Provisions 101 through 150.
641.3.04 Fabrication
A. Guardrail Anchorages, Mounting Devices, and Brackets Fabricate and install guardrail anchorages, mounting devices, brackets, and other appurtenances according to the plan details or as approved by the Engineer.
641.3.05 Construction
A. Erection of Posts 1. Wood guardrail posts shall not be used at any location except as required for guardrail terminals and guardrail anchorage. 2. Set the posts in post holes or drive them vertically at the positions, depth, spacing, and alignment shown on the plans. 3. Install posts for Guardrail on bridges or other structures as detailed on the plans. 4. Backfill post holes to the ground line with approved material tamped in place in layers of not more than 4 in. (100 mm) thick. 5. If posts are driven, protect the tops of the posts with a suitable driving mat or cap. Remove and replace posts damaged during driving, at no additional cost. 6. Backfill the post holes that are drilled in rock as indicated on the plans or directed by the Engineer. 7. Remove and reset posts that are out of alignment or too low in grade. Do not cut off posts that are too high; drive them to the proper elevation. Do not deviate more than 1/4 in. (6 mm) vertical and horizontal post alignment. 8. Fit the posts with an offset block according to this specification and plan details. 9. Set additional posts and appurtenances, when required, according to the requirements of this Section and the plan details. 10. When necessary to place posts in existing pavement, slope paving, etc., exercise extreme care in the cutting process, protect the adjacent areas, and remove all loose material. Cut holes in the existing paved area by drilling or sawing according to the plan details. Replace the pavement material according to the plan details with a controlled low strength flowable fill that has a maximum 28-day compressive strength of 100 psi according to Section 600. B. Erection of Rail Erect the rails to attain a smooth, continuous rail line that conforms to the line and grade of the highway. Determine the height of the rail from the dimensions shown on the plans. Use bolts long enough to extend at least 1/4 in. (6 mm) beyond the nuts after they are firmly tightened. Install reflectorized washers on guardrail and anchorages. Where double faced guardrail is located on the inside shoulder of medians, install reflectorized washers only on the side which is nearest to traffic. In stall reflectorized washers according to this specification and plan details. C. Damaged Spelter Coating Repair damaged spelter coating according to the requirements of Section 645. D. Guardrail Terminals Guardrail terminals shall be designed for use with “W” beam guardrail installations, which has been approved by FHWA as meeting NCHRP-350 and/or MASH Test Level 3 (TL-3) and listed on the Office of Materials and Testing Qualified Products List QPL-64. Where the terminal is connected to “T” beam guardrail installations, a transition is required as shown in the Standard details. Construct guardrail terminals according to the manufacturer’s requirements except for the grading which will be as shown in the Plans and as directed by the Engineer. Obtain copies of the manufacturer’s details and installation instructions and provide copies of the same to the Engineer prior to the installation of the unit. Provide a FHWA letter of approval for NCHRP-350 and /or MASH, TL-3 compliance of the guardrail terminal to be used. Yellow and black nose striping, as shown on the Plans will be required on all guardrail terminal.
641.3.06 Quality Acceptance
General Provisions 101 through 150.
641.3.07 Contractor Warranty and Maintenance
General Provisions 101 through 150.
641.4 Measurement
A. Guardrail Guardrail of the type specified is measured in linear feet (meters), including terminal sections when installed. Measurement does not include guardrail terminals or guardrail anchorage assembly. When double faced guardrail of the type specified is installed, the single guardrail on each side of the posts is not measured separately. Each single rail is a component part of the double-faced guardrail installation. B. Guardrail Terminal and Anchorage Assembly This Item is measured by the number of each type installed according to the details shown on the plans. C. Guardrail Posts All lengths of guardrail posts when shown in the Plans or Proposal as a separate payment Item are measured by the Unit.
641.4.01 Limits
General Provisions 101 through 150.
641.5 Payment
Guardrail, of the type specified, complete in place including posts, offset blocks, and hardware will be paid for at the Contract Price per linear foot (meter). Guardrail terminals and guardrail anchorage assemblies will be paid for at the Contract Price per each assembly, complete in place. All lengths of guardrail posts when shown in the Contract documents as a separate Pay Item will be paid for at the Contract Unit Price. Payment is full compensation for furnishing the posts, offset block, hardware, and Work to complete the Item. For projects that do not include grading as a Pay Item, payment for guardrail and guardrail anchorage systems on shoulders includes: • Embankment material for shoulders as shown on the Standard Details or plans • Compacting embankment material for shoulders to the approximate density of the surrounding soils • Removing existing vegetation and obstructions before placing the embankment • Grassing the reconstructed area according to Section 700 Payment will not be increased or decreased when wood offset blocks are added to or substituted for steel or plastic offset blocks. Payment will be made under: Item No. 641 Guardrail, type____ Per linear foot (meter) Item No. 641 Double faced guardrail, type____ Per linear foot (meter) Item No. 641 Guardrail for bridges, type____ Per linear foot (meter) Item No. 641 Double guardrail for bridges, type____ Per linear foot (meter) Item No. 641 Guardrail, Type T, Modified offset block Per linear foot (meter) Item No. 641 Guardrail terminal, type ____ Per each Item No. 641 Guardrail anchorage, type___, Per each Item No. 641 Guardrail posts (all lengths) Per each
641.5.01 Adjustments
General Provisions 101 through 150.
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