606.01 Description
This work is the furnishing, installing, removing, resetting, replacing, and revising metal beam guardrail, cable guardrail, and box beam guardrail.
606.02 Materials
Furnish steel beam guardrail, cable guardrail, and box beam guardrail materials in accordance with the following section and subsection requirements: Box Beam Guardrail ................................................ Detailed Drawings Guardrail Reflectors ................................................ 704 and Detailed Drawings Steel Beam Guardrail and Fittings ........................... 705.01.1 Steel Guardrail Post ................................................ 705.01.5 Wood Guardrail Posts and Blocks ........................... 705.01.2 Wire Rope and Connecting Hardware ..................... 705.02 Furnish all new materials. Do not use refurbished material unless specified in the contract documents.
606.03 Construction Requirements
606.03.1 General
Install guardrail meeting the requirements of Detailed Drawings and the contract. Install all guardrail, terminal sections, and impact attenuators according to the manufacturer’s instructions. Submit the installation instructions at least 15 calendar days prior to the installation. Submit a completed form MDT-CON-606-03 prior to installing guardrail items. At the Project Manager’s request, provide documentation that each item or system of guardrail installation meets NCHRP 350 or MASH requirements. The Project Manager will establish the line and grade for the terminal sections. Establish the line and grade between the terminal sections. Correct all vertical and horizontal misalignment to the specified line and grade at Contractor expense. Optional terminal sections must be installed within 12 hours from the time the rail is exposed when conditions prevent completion in one working day. Approved temporary end treatments must be installed to protect blunt ends, ends of barriers, fixed objects, or other obstacles within the clear zone if left for more than 12 hours. Temporary end treatments are not measured for payment. Place, at Contractor expense, object markers at maximum 50-foot (15.2 m) spacing to delineate partial installation areas when work on those installations is not active. Excavate the postholes and drive the posts using methods and equipment that do not damage the adjacent pavement. Stop post driving that heaves the adjacent pavement more than ½-inch in 10 feet (13 mm in 3 m), measured using a 10-foot (3 m) straightedge parallel to the pavement. Level and repair all damaged surfaces around the installed posts. Use only steel or wood guardrail posts for new metal beam guardrail runs unless wood posts are specified. Where the contract specifies extending an existing guardrail run, the Contractor may use either the existing post type or other approved post types in the extension. Use the post type specified for terminal sections. 606 –GUARDRAIL 2020 EDITION V5.1 606-2 When wood posts and blocks are damaged, cut or bored after treatment, treat the injuries in accordance with Subsection 706.04.1.
606.03.2 Installing Posts
Complete guardrail widening prior to new post installation. Install posts in accordance with manufacturer recommendations. Drive posts unless conditions require excavation and backfilling. If the posthole is excavated, compact the posthole bottom, insert the post, and backfill and compact around the post in 6-inch (150 mm) loose layers ensuring the material is at optimum moisture before placing and compacting the next layer. Maintain the post line and grade. Replace all posts damaged by post driving. Maintain the post alignment as the posts are driven. Fill the area between the surrounding ground and the post by backfilling and tamping. Re- compact the loose material around the post and level the area as directed. Remove, replace, or re-install misaligned, loose, or damaged posts at Contractor expense. When driving wood posts, pilot holes approximately 6 inches (150 mm) in diameter may be used when necessary.
606.03.3 Metal Beam Guardrail Erection
Install metal beam guardrail, including the terminal sections and bridge approach sections as shown in the Detailed Drawings and in accordance with the contract. Splice the metal rail sections with the lap in the direction of traffic. Construct splices, laps, and terminal connectors as shown in the Detailed Drawings and in accordance with the contract. Splice the terminal connectors for attaching the rail sections to the bridge ends by lapping as shown in the Detailed Drawings. Tighten the bolts through the splices and mounting bolts “snug tight”. Ensure the bolts project at least ¼-inch (6 mm) beyond the nut. Place the bolt heads on the traffic side of the guardrail. Drilling or cutting in the field is only allowed for special connections and sampling. Do not use cutting torches to cut guardrail or make bolt holes. Obtain Project Manager approval prior to drilling bolt holes or cutting guardrail for special connections. Paint holes, slots, or cut ends in metal guardrail caused during installation with an approved galvanizing paint. Spot paint all bruised, broken, scaled, or damaged spelter coating on metal parts following the paint manufacturer’s recommendations after the guardrail is installed.
606.03.4 Stiffened Guardrail Sections
Construct stiffened guardrail sections as shown in the Detailed Drawings .
606.03.5 Box Beam Guardrail
Construct box beam guardrail and bridge approach sections as shown in the Detailed Drawings.
606.03.6 Cable Guardrail
Furnish and install cable guardrail and terminal sections in accordance with the Detailed Drawings an d the contract. Install the posts plumb without damaging the post and its protective coating. For terminal sections, set the end posts, backfill and machine compact the backfill material in 4-inch (100 mm) lifts. Install reflectors in accordance with Section 704 on every other post in the guardrail run excluding posts in the terminal sections that curve away from the driving lanes. 2020 EDITION V5.1 GUARDRAIL – 606 606-3
606.03.7 Raise Guardrail
Unbolt the W-beam and block from the guardrail post, raise and re-bolt through the upper hole of the guardrail post.
606.03.8 Remove Guardrail
Remove and salvage the existing guardrail from the specified locations in accordance with Section 202. Replace all guardrail damaged during removal at Contractor expense. Dispose of removed materials not designated to be salvaged. Load all salvaged guardrail materials from the project, transport and unload it at the specified location or as directed. Backfill and compact the postholes left from post removal using clean material or crushed base or top surfacing, to the base of the adjacent bituminous surfacing. Apply a light asphalt spray to the hole sides and bottom and backfill with asphalt surfacing. Compact the plant mix surfacing as specified. Do not cut off and leave existing posts in place.
606.03.9 Revise Guardrail Elements
Revise the guardrail elements as specified. The items include but are not limited to W-beam sections, bridge approach sections and terminal sections.
606.03.10 Nested W-Beam Guardrail Sections
Construct nested guardrail as shown in the Detailed Drawings.
606.03.11 Reset Guardrail Items
Reset existing guardrail items to the specified locations in the contract. Meet all the requirements of this section and the Detailed Drawings. Remove the rail elements or cable, and completely remove the post. Backfill and compact the posthole bottom, re-install the posts, and compact the backfill around the post in accordance with Subsection 606.03.2, and replace the rail elements or cable to the specified height. Replace all guardrail materials damaged during the work at Contractor expense. Correct all horizontal and vertical alignment in the guardrail to the specified line and grade.
606.03.12 Optional Terminal Sections
Supply the optional terminal section(s) as listed in the contract meeting the requirements for the specified item. Furnish MASH tested W-Beam terminal sections listed on the QPL. The items include but are not limited to metal guardrail terminal sections and box beam terminal sections. When new terminal sections tie into existing rail, it may be necessary to raise the existing rail to match the new terminal section height. Transition a minimum of 50 feet (15.2 m).
606.03.13 Guardrail End Terminal Section Widening
Furnish and place embankment material or gravel to widen the roadway to accommodate guardrail extensions or new optional terminal sections as shown in the Detailed Drawings. This work may also include the removal of sanding material and shaping of the existing soils to achieve positive drainage. Compact widening to a minimum of 90% of maximum density with no optimum moisture requirement.
606.04 Method of Measurement
606.04.1 Metal Guardrail
Metal guardrail, excluding terminal sections, is measured by the foot (meter) from center-to- center of the end posts of each section. 606 –GUARDRAIL 2020 EDITION V5.1 606-4
606.04.2 Optional Terminal Sections
Optional terminal sections are measured by the unit as shown in the Detailed Drawings, unless otherwise specified, for each type specified. When transitions are needed to tie into existing rail, the labor and equipment necessary to perform this work is not measured for payment and is to be included in the price for optional terminal sections.
606.04.3 Bridge Approach Sections
Bridge approach sections, including tapered curbs, are measured by the unit for each type specified as shown in the Detailed Drawings.
606.04.4 Stiffened Guardrail Sections
Stiffened guardrail sections are measured by the foot (m) from center-to-center of the end posts of each stiffened section as shown in the Detailed Drawings.
606.04.5 Box Beam Guardrail
Box beam guardrail is measured by the foot (m), excluding the terminal sections, as shown on the Detailed Drawings.
606.04.6 Cable Guardrail
Cable guardrail is measured by the foot (m), excluding the terminal sections.
606.04.7 Cable Guardrail Terminal Sections
Cable guardrail terminal sections are measured by the unit.
606.04.8 Impact Attenuators
Impact attenuators are measured by the unit as specified in the contract.
606.04.9 Raise Guardrail
Raise guardrail, including terminal sections, is measured by the foot (m) from center-to- center of the end posts of each section.
606.04.10 Remove Guardrail
Remove guardrail is measured by the foot (m) from center-to-center of end posts of each section removed. Material and equipment necessary for backfill and compaction of post holes is not measured for payment and is to be included in the price for remove guardrail.
606.04.11 Revise Guardrail Elements
Revise guardrail elements are measured by each element revised, as specified in the contract.
606.04.12 Nested W-Beam Guardrail Sections
Nested guardrail is measured by the foot (m), as shown in the Detailed Drawings .
606.04.13 Reset Guardrail Items
Reset guardrail items are measured by the unit as specified in the contract. Material and equipment necessary for backfill and compaction of post holes is not measured for payment and is to be included in the price for reset guardrail.
606.04.14 Guardrail End Terminal Section Widening
Optional terminal section widening is paid by each end section completed. Include the cost of topsoil, seeding and fertilizer used in the widened areas in the unit bid price for optional terminal section widening. 2020 EDITION V5.1 GUARDRAIL – 606 606-5
606.05 Basis of Payment
Payment for the completed and accepted quantities is made under the following. Pay Item Pay Unit Box Beam Guardrail Foot (m) Bridge Approach Section Each Cable Guardrail Foot (m) Cable Guardrail Terminal Section Each Guardrail End Terminal Section Widening Each Impact Attenuators Each Metal Guardrail Foot (m) Nested Guardrail Sections Foot (m) Optional Terminal Section Each Raise Guardrail Foot (m) Remove Guardrail Foot (m) Reset Guardrail Foot (m) Reset Guardrail Items Unit Stiffened Guardrail Sections Foot (m) Revise guardrail elements is paid for in accordance with the appropriate section.
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