DESCRIPTION
618.01.01 General. This work consists of constructing guardrail systems , furnishing and installing guardrail
terminals, and reconstructing guardrail systems. MATERIALS
618.02.01 General. Material shall conform to the following Sections:
Portland Cement Concrete ................................ ..................................................................................................................... Section 501 Reinforcing Steel ................................ .................................................................................................................................... Section 505 Guardrail Materials ................................................................................................................................................................. Section 720 Use wood or metal posts. Use the same type of post, where there are optional post types, for the e ntire project. Give wood posts and blocks a preservative treatment by pressure processes after fabrication according to Section 718. Other approved products for guardrail offset blocks may be used in lieu of wood blocks. The optional products approved for use as guardrail offset blocks are available from the manufacturers listed in the QPL. Rail members having a radius of curvature of 46 m (150 ft) or less shall be fabricated with the required radius. Field bending will not be allowed. Stencil the radius of curvature on the back of each section in numerals 60 mm (2.5 in.) in height.
a.Guardrail Terminals. Flared guardrail terminals shall be the type for installations which flare to 1.2 m (4 ft) away from the shy line parallel to the travel lanes. Tangential guardrail terminals shall be the type for installations parallel to the travel lanes. Manufacturers of the appropriate guardrail terminals are listed in the QPL. Select a product for flared guardrail terminals and install that same product at all flared guardrail terminal locations. Select a product for tangential guardrail terminals and install that same product for all tangential guardrail terminal locations. Submit the manufacturer’s shop drawings, foundation details, installation recommendations, and any other pertinent information for the guardrail terminals. Receive approval for the exact model of guardrail terminal proposed, prior to installation. Furnish and install the units with all parts and materials necessary for them to perform as designed.
b.Trailing End Anchors. The 19 mm (3/4 in.) cable and fittings shall conform to Subsection 720.03.03. Use cable clips or a swaged fitting and clevis to attach the cable to the anchor rod. Cable clips shall be commercial quality drop forged galvanized steel. Machine the swaged fitting from hot -rolled bars conforming to AISI C1035, and anneal suitably for cold swaging. Galvanize the swage fitting before swaging. Drill a lock pin hole to accommodate a 6 mm (1/4 in.), plated, spring steel pin t hrough the head of the swage fitting to retain the stud in proper position. Stamp the manufacturer’s identifying mark on the body of the swage fitting. The 25 mm (1 in.) diameter threaded stud shall conform to ASTM A449 after galvanizing. Before galvanizi ng, mill a 10 mm (3/8 in.) slot for the locking pin in the stud end. The swaged fittings, stud and nut assembly shall develop a minimum breaking strength of 190 kN (21.4 tons). The clevises shall be drop forged galvanized steel and shall develop a minimu m breaking strength of 190 kN (21.4 tons). 618 GUARDRAIL Fabricate the anchor rods from steel conforming to ASTM A36, ASTM A572, or ASTM A576, Grades 1018, 1019, 1021 or 1026. Hot forge or form the eyes with full penetration welds. After fabrication, thermally stress relieve anchor rods with eyes that have been formed with any part of the eye below 871 °C (1,600 ° F) during the forming operation or with eyes that have been closed by welding before galvanizing. The anchor rod, after galvanizing shall develop a minimum strength of 220 kN (24.7 tons). CONSTRUCTION
618.03.01 General. Drive wood posts, with or without pilot holes, or place in drilled holes. Backfill any space
around the wood posts in layers with approved material. Thoroughly ram backfill with an iron tamping tool in such a manner as not to displace the bottom of posts from correct alignment. Drive steel posts. If ground conditions are such that pilot holes are necessary to prevent damage to posts during driving, fill any space around steel posts after driving with sand or other approved material. Set posts plumb, except on superelevated curves set perpendicular to the roadbed. Front faces of posts shall form a straight line, except on curves where they shall be a uniform distance from the centerline of the ro adway. Furnish guardrail beam elements in 3.810 m (12.5 ft) or 7.620 m (25 ft) lengths. After erection, the rail shall be true to line and grade and shall have the proper tension in the rail plates. Do not disturb posts during the erection of the rail. I f necessary, temporarily brace posts to prevent displacement. Thoroughly wire brush and remove all loose and cracked coating from galvanized surfaces that are abraded or damaged. Paint the cleaned abraded or damaged areas with 2 coats of paint having a hi gh zinc dust content conforming to MIL- P-21035. Clean all soiled exposed surfaces of the metal guardrail.
a.Guardrail Terminals. Excavate any material encountered for the construction of the posts for guardrail terminals according to Section 206. Set and backfill posts for the guardrail terminals in the same manner as for the guardrail posts. Install guardrail terminals according to the plans and the manufacturer’s recommendations.
b.Trailing End Anchors. Drill or dig holes for the concrete anchor blocks. Furnish and place reinforcing steel for the anchor blocks according to Section 505. Construct concrete for the anchor blocks according to Section 502. Place concrete against undisturbed material of the excavated holes. Form the top 300 mm (12 in. ) of the holes, if required. After installation and before backfilling, coat the portion of the anchor rod to be buried in earth with a minimum 0.5 mm (20 mils) thickness of coal tar enamel conforming to AWWA Standard C203 or a coal tar epoxy conforming to Steel Structures Painting Council Specification No. 16, Coal -Tar Epoxy -Polymide Black Paint, or Corps of Engineers Specification, Formula C -200a, Coal -Tar Epoxy Paint. Tighten anchor cables after the concrete anchor has cured for at least 5 days.
618.03.02 Reconstruct Guardrail. Carefully reconstruct guardrail to bring compliance with the Standard Plans.
Furnish any new materials necessary to reconstruct the guardrail. The Department may furnish new materials to be used in lieu of salvaged materials. METHOD OF MEASUREMENT
618.04.01 Measurement. New or reconstructed guardrail will be measured by the linear meter (linear foot)
measured along the front face of the rail between centers of posts. Guardrail terminals, trailing end anchors, buried end anchor s, anchor terminals, guardrail -bridge rail connections, or guardrail -barrier rail connections, will be measured by the each. GUARDRAIL 618 Guardrail posts and guardrail blocks will be measured by the each only when they are listed as separate items in the proposal. Guardrail posts and guardrail blocks will only be measured for payment at designated locations as shown on the plans and shall otherwise be considered as included in other items of work. The additional guardrail beam elements required to construct double beam rail (nested beams) will not be measured or paid for directly. Guardrail quantities shown on the plans are approximate. During construction the need for guardrail will be reviewed and a revised amount of guardrail required will be provided. Furnish only guardrail materials required by the Engineer’s revised list. BASIS OF PAYMENT
618.05.01 Payment. The accepted quantities, measured as provided above, will be paid for at the contract
price per unit of measurement for the pay items listed below that are shown in the proposal. Payment will be full compensation for the work prescribed in this Section. Payment will be made under: Pay Item Pay Unit Galvanized Guardrail ....................................................................................................................................... Linear Meter (Linear Foot) Galvanized Guardrail (Triple Corrugation) ................................ ........................................................................ Linear Meter (Linear Foot) Reconstruct Guardrail ...................................................................................................................................... Linear Meter (Linear Foot) Guardrail -Bridge Rail Connection (Triple Corrugation) ....................................................................................................................... Each Guardrail -Barrier Rail Connection (Triple Corrugation) ...................................................................................................................... Each Guardrail Terminal (Flared) ............................................................................................................................................................... Each Guardrail Terminal (Tangential) ......................................................................................................................................................... Each Trailing End Anchor ................................ ........................................................................................................................................... Each Buried End Anchor ............................................................................................................................................................................ Each Anchor Terminal ................................ ................................................................................................................................................ Each Guardrail Post ................................................................................................................................................................................... Each Guardrail Block ................................................................................................................................................................................. Each SECTION 619 OBJECT MARKERS AND GUIDE POSTS DESCRIPTION
619.01.01 General. This work consists of furnishing and installing object markers and guide posts.
MATERIALS
619.02.01 General. Material shall conform to the following Section:
Object Markers and Guide Posts ............................................................................................................................................ Section 721 Flexible Type 2 Object Markers capable of rebounding after impact may be substituted for the metal Type 2 Object Markers indicated in the plans. Use flexible Type 2 Object Markers listed in the QPL. When flexible guide posts are specified for use, use flexible guide posts listed in the QPL. The color of flexible guide posts shall be white and the reflective sheeting shall be as indicated on the plans. The date of manufacture shall be permanently stamped on flexible guide pos ts. CONSTRUCTION
619.03.01 General. Assemble, fasten, set, and align target members and reflectors appropriate to the color
involved. Tighten all fastenings. Install flexible guide posts according to the manufacturer’s recommendations and as specified. Place object markers at approved locations. Install Flexible Type 2 Object Markers according to the manufacturer’s recommendation and as specified. Place guide posts and object markers when ordered for the protection of the public traffic. Replace guide posts and object markers which may be subsequently damaged by public traffic. Replacement guide posts and object markers will also be measured and paid for at the contract unit bid prices. METHOD OF MEASUREMENT
619.04.01 Measurement. Object markers and guide posts will be measured by the each.
BASIS OF PAYMENT
619.05.01 Payment. The accepted quantities, measured as provided above, will be paid for at the contract
price per unit of measurement for the pay items listed below that are shown in the proposa l. Payment will be full compensation for the work prescribed in this Section. Guide posts will be paid for on an each basis and each type (rigid or flexible), as specified in the proposal, will be considered separately. Note that the metal guide posts are classified as the rigid type of guide posts. Payment will be made under: Pay Item Pay Unit Guide Posts (type) ............................................................................................................................................................................ Each Object Markers (type) ........................................................................................................................................................................ Each
Source: Nevada Standard Specifications for Road and Bridge Construction, 2014 Edition. Pages 365–368 of 610.