- 725 - SECTION 902 -- GUARDRAIL AND GUARD POSTS
902.01 Description
1.This work consists of furnis hing and erecting guardrail and guard posts at locations shown in the contract.
2.Cable guardrail consists of wi re cables supported by cable mounts that are attached to steel posts.
3.W-beam and thrie-beam guardra il consists of rigid beam elements bolted to the posts with offset blocks. If shown in the contract or approved by the Engineer, the offset blocks may be omitted.
902.02 Material Requirements
1.Materials shall conform to the requirements in Table 902.01 or the contract. Table 902.01 Material Requirements Applicable Materials Section Reinforcin g Steel ............................................................... .1020 Steel Guardrail Posts, Special Posts, and Offset Blocks ... .1067 “W” and “Thrie”-Beam Guardrail ........................................ .1066 Wood Guardrai l Posts........................................................ .1075 Concrete Aggregate 1033
2.The concrete for use in guardrail anchors and footings shall be a readily available, commercially designed concrete mixture or Contractor- produced concrete, which shall achieve a minimum compressive strength of 3000 psi (20 MPa) at 28 days. The cement shall be Type I, Type II, or Type III. The aggregate shall be from acceptable sources.
3.Cable Guard Rail and Fittings a. The cable shall be 3/4 inch in diameter and shall conform to the requirements of AASHTO M 30. The cable shall, unless otherwise specified, meet the requirements for “T ype I” rope, with “Class A” galvanized coating.
b.Fittings shall be as shown in the contract and as required in AASHTO M 30.
c.All anchor rods, plates and fittings shall conform to the physical requirements of ASTM A 36. Turnbuckl es and clevises shall be steel forgings conforming to the requirements of ASTM A 668, Class B. The forgings shall be annealed prior to being machined.
d.Tension spring assemblies shall be as shown in the contract. Tension spring assemblies, when tested as installed in a normal cable guard rail installation, shall develop a mini mum tensile strength of 25,000 pounds per 3/4 inch cable. The coil spring shall conform to the requirements of ASTM A 689.
e.All fittings (rods, plates, turnbuckles, clevises, tension spring assemblies) shall have a uniform coating of zinc as required in AASHTO M 30.
902.02 Guardrail and Guard Posts
- 726 - 4. The Contractor shall order guardr ail items as shown in the contract unless the Engineer furnishes a field checked list of items, lengths, and locations.
902.03 Construction Methods
1.Guardrail Posts
a.The Contractor shall set posts plumb, firm, and spaced as shown in the contract and to lines and grades given.
1.The Contractor may elect to drive, rather than set the posts in prebored holes.
2.Posts damaged when driven into the ground will be rejected. The Contractor shall remove and replace the posts with acceptable materials.
3.If the Engineer determines that damage is occurring to the surfaced shoulder during post placem ent due to the Contractor's driving operation, the Engineer will require that the posts be set in prebored holes.
b.W-Beam and Thrie-Beam G uardrail Posts: The Contractor shall construct a blockout in the surfacing around each post as shown in the contract documents.
c.Cable Guardrail Posts
1.The 8 foot end posts shall be driven.
2.The Contractor shall seal the joint around the posts and any cracking that may occur in the su rfacing. The hot pour sealant shall comply with Section 519. This work will be considered subsidiary to the Cable Guardrail.
d.Any damage to galvanizing shall be repaired in accordance with Repair Method 2 as described in Section 1061.
e.All areas where the surface of treated timber is broken by cutting, boring, or other means shall be thoroughly coated with 3 applications of preservative. Each application shall be reasonably dry before the next coat is applied.
f.Backfill of Blockouts
1.When blockouts are required in a surfaced area, the Contractor shall backfill all post holes with material approved by the Engineer. The material shall be compacted leaving a space around the post as defined in the contract. This remaini ng part of the hole shall be backfilled with granular material and approved bituminous material or flowable fill concrete placed to the elevation of the surrounding surfacing as shown in the contract. The material near the post shall be sloped to help any water run off away from the post.
2.Posts placed in other than bituminous and concrete surfacing shall be backfilled with material approved by the Engineer and placed to the elevation of the existing surface.
2.W-Beam and Thrie-Beam Guardrail
a.The beam elements shall be st raight and of uniform section. Guardrail and Guard Posts 902.04 - 727 - b. Curved elements described in the contract shall be manufactured with the curve.
c.Warped or deformed elements will be rejected. d. The edges of the beam elements shall be smooth after erection.
3.Bridge approach sections shall be mounted directly to the bridge with cast in place welded assemblies of threaded inserts or bolts through bridge rail as shown in the contrac t. Curb mountings, anchor bolts, and incidentals will be considered as par t of the bridge approach sections.
4.The Contractor shall submit End Treatment plans.
902.04 Method of Measurement
1.Cable Guardrail
a.Cable guardrail is measured by the linear foot (meter). The Department will compute the cable guar drail length in linear feet (meters) from terminal section to terminal section, excluding intermediate anchorage sections.
b.Terminal anchorage sections and intermediate anchorage sections will be measured as single units complete and in place as shown in the contract.
2."W"-Beam and "T hrie"-Beam Guardrail
a."W" and "thrie"-beam guardrail is measured by the linear foot (meter). The Department will compute the "W" and "thrie"-beam guardrail length in linear feet (meters) from c enter to center of the end splices and shall not include the distance of the section of rail projecting beyond these points.
b.When "W" and "thrie"-beam g uardrail is installed in conjunction with bridge approach sections, the pay length of these items shall be measured to the limits indicated in the contract.
c.When "W" and "thrie"-beam g uardrail is installed in conjunction with terminal end sections, the pay length of these items shall be measured to the limits indicated in the contract.
d.Guardrail end treatment is measured by the each.
e.W-Thrie Beam Transition Section is measured by the each. f. Special guardrail posts furnished and installed in conjunction with "W" and "thrie"-beam guardrail will be measured by the each.
902.05 Guardrail and Guard Posts
- 728 - 902.05 -- Basis of Payment
1.P a y I t e m P a y U n i t Cable Guardrail Linear Feet (LF) [Meter (m)] Intermediate Anchorage Sections Each (ea) Terminal Anchorage Sections Each (ea) Bridge Approach Sections Each (ea) Special Bridge Approach Section Each (ea) W-Beam Guardrail Linear Feet (LF) [Meter (m)] Thrie-Beam Guardrail Linear Feet (LF) [Meter (m)] W-Thrie Beam Transition Section Each (ea) Terminal Sections _____ Each (ea) Special Guardrail Posts Each (ea) Special Guardrail Posts _____ Each (ea) Guardrail Adapter _____ Each (ea) E a c h ( e a ) Guardrail End Treatment _____ Each (ea) End Anchorage Assembly Each (ea) B u l l n o s e E a c h ( e a ) 2. Terminal end shoes, when required in the contract, shall not be measured for payment but shall be cons idered subsidiary to the items for which direct payment is provided.
3.Guardrail post will be consider ed subsidiary to the guardrail item unless otherwise shown in the contract.
4.Payment is full compensation for all work described in this Section. - 729 - SECTION 903 -- REMOVE AND RESET GUARDRAIL
903.01 Description
1.Removing guardrail shall include the removal of all cable, approach sections, terminal sections, anchorage sections, and beam guardrail materials, fittings, and posts from locations shown in the contract or designated by the Engineer. Concrete anchors shall be removed in their entirety and disposed of by the Contractor.
2.Resetting guardrail shall include setting guardrail salvaged from the project or furnished and delivered to the project by others as indicated in the contract. New anchors shall be furnished by the Contractor. The Contractor shall furnish all new posts, offset blo cks, hardware, and incidentals required to install the salvaged rail and cable elements.
903.02 Material Requirement
1.New materials, replacement materials, and concrete shall conform to the requirements of Section 902.
903.03 Construction Methods
1.“Remove and Salvage Guardrail” a. The Contractor shall remove and salvage the guardrail as shown in the contract. The salvaged guardrail materials shall be stockpiled as indicated in the contract.
b.Cable shall be rolled on spools, and the length of cable on each spool shall not exceed 2,000 feet (610 m).
c.(1) Salvaged materials shall be stored on or near the right-of- way at locations designated by the Engineer.
2.Hardware shall be placed in suitable containers. (3) No more than 55 pounds (25 Kg) of salvaged material shall be placed in a single container.
d.The Contractor removing the existing guardrail shall replace all materials damaged during removal at no additional cost to the Department.
e.All materials that the E ngineer determines are not salvageable or needed by the Department shall bec ome the property of the Contractor. The Contractor shall remove all nons alvagable materials from the project site and properly dispose these materials in accordance with all-applicable laws and regulations.
2.“Remove Guardrail”
a.The Contractor shall remo ve the guardrail and all materials belong to the Contractor and mu st be removed from the site.
3.“Reset Guardrail” a. The Contractor shall reset the guardrail at the locations shown in the contract or as directed by t he Engineer. The work shall be done in accordance with the requirements of Section 902.
903.04 Method of Measurement
1.“Reset Guardrail” is measur ed by the liner foot (meter). The Department will compute the length of guardrail reset by the linear foot
Source: Nebraska Standard Specifications for Highway Construction, 2017 Edition. Pages 759–762 of 1,048.