- 521 - SECTION 707 -- REINFORCEMENT
707.01 Description
1.This work shall consist of furnishing and placing reinforcing steel as required by these Specifications and as shown in the contract.
707.02 Material Requirements
1.Reinforcing steel shall conform to the requirements as described in Sections 1020, 1021, 1023, and 1024.
2.Two samples of all reinforcing steel (coated and uncoated) shall be submitted to the Department's Materials and Research Division for testing. The length of each sample shall be 6 linear feet (1.8 m).
707.03 Construction Methods
1.Fabrication:
a.Reinforcing bars shall be shipped in standard bundles, tagged and marked in accordance with the Code of Standard Practice of the Concrete Reinforcing Stee l Institute. When reinforcing bars are not shipped from tested and approved stock, the identification of all reinforcing bars (manufacturer, heat number, and size) shall be maintained by the fabricator throughout the fabricatio n process to assure that the fabricated bars are identified with proper tags for final shipment to the job site.
b.The Contractor shall bend reinforcing bars without the use of heat to the dimensions and shapes shown in the contract, and bars having cracks or splits at the bends shall be rejected.
c.Epoxy Repairs: (1) The epoxy coated rebar shall be free of any cracking or debonding. The Contractor may repair epoxy coated reinforcing bars that show any visible evidence of cracking or disbonding of the coating in the bend area with approval of the Engineer.
2.Epoxy coatings cut, broken, or abraded shall be repaired before rusting of the bar occurs.
3.All patching shall be done as provided in Section 1021. d. All reinforcing steel sha ll be identified and tagged as required in Subsection 1021.03.
2.Protection of Material:
a.The Contractor shall protec t reinforcing steel from damage at all times. When placed in the work, the reinforcing steel shall be free from dirt, paint, grease, oil, rust, or other foreign substances. The Engineer shall be the final judge as to acceptability of the reinforcing material's condition.
b.Reinforcement with any appreciable reduction in section dimensions caused by corrosion will be rejected.
3.Placing and Fastening: a. The Contractor shall place all reinforcement in the position shown in the contract, and it shall be held securely in position.
707.03 Reinforcement
- 522 - b. Fastening:
1.Reinforcing bars shall be tied at all intersections, except when the spacing is less than 1 foot (300 mm) in both direction, in which case alternate intersections shall be tied.
2.Welds at all points of intersection of the wire in welded steel wire fabric shall be of sufficient strength that they will not be broken during handling and placing.
3.Tie wire for epoxy coated bars shall be plastic coated. Plastic clips suitable for the purpose may be used.
c.Positioning and Support: (1) The Contractor shall position steel reinforcement in concrete walls at the proper clearance from forms by approved chairs, stays, or hangers.
2.Reinforcing steel in concrete decks and slabs shall be positioned on plastic coated supports or chairs to accurately maintain the specified clearance to the surface of the concrete. Supports shall be spaced at distances not greater t han 3 feet for #4 top bars or 4 feet for all other reinforcing.
3.When wire bar support units are placed in continuous lines, they shall be so placed that the ends of the supporting wires are lapped to lock the last legs of adjoining units. No reinforcing shall be placed more than 2 inches (50 mm) beyond the last leg at the end of any continuous support run.
4.Reinforcing steel on bar supports shall not be used to support runways for construction equipment. If such runways are used, they shall be supported independently.
5.Bar support units shall be standard products from a reputable manufacturer of such item s. Properly sized supports shall be furnished in sufficient numbers, manufactured to serve their intended purpose, and capable of carrying imposed loads without measurable deflection or displacement of the re inforcing steel. The type and adequacy of supporting units shall be at least equal to that recommended by the Concrete Reinforcing Steel Institute's Manual of Standard Practice .
6.Bar supports which are at exposed concrete surfaces shall be corrosion resistant as described in the Concrete Reinforcing Steel Institute's Manual of Standard Practice .
d.Welding or flame cutting on reinforcing steel is prohibited unless specifically authorized by the Engineer.
e.Fiber reinforced concrete support spacers must have at least 4% Polyamide fiber. The flexural strength shall be at least 580 psi (4 MPa) and the compressive strength not less than 9,000 psi (62 MPa). The coefficient of expansion must be the sa me as for the cast-in-place concrete.
4.Splicing: a. The Contractor shall furnish all reinforcing steel in full lengths, except where splices are indicated in the contract. Splices in adjacent bars shall be staggered. Reinforcement 707.05 - 523 - b. The Contractor shall splice bars by lapping the ends. The overlap length shall be as shown in the contract or the Construction Manual. Lapped splices shall be made by securely wiring the bars in contact, maintaining alignment and clearances.
c.Spiral reinforcement shall be held in place by wiring to the main reinforcing. Pitch shall be main tained by adequate spacers. Splices shall be made by lapping 1.5 turns.
d.The Contractor shall overlap sheets of welded steel wire fabric reinforcement to maintain uniform streng th and fasten them securely at the ends and edges. The edge lap shall not be less than one mesh opening in width, and the end lap shall be not less than 1 foot (300 mm).
707.04 Method of Measurement
1.All reinforcing steel used in concrete for bridges, box culverts, culvert headwalls, retaining walls, and all other reinforced concrete structures is measured in pounds (kilograms). Payments will be based on the plan quantities when the structure is built according to the contract.
707.05 Basis of Payment
1.P a y I t e m P a y U n i t Reinforcing Steel ______ Pound (lb) [ k i l o g r a m ( k g ) ] Epoxy Coated Reinforcing Steel _____ Pound (lb) [ k i l o g r a m ( k g ) ]
2.Welded steel wire fabric (wire mesh) is subsidiary to the relevant concrete pay item.
3.Payment is full compensation for all work described in this Section. Acceptance of the support spacer s will be based on a certificate of compliance furnished by the supplier.
707.05 Reinforcement
- 524 - - 525 - SECTION 708 -- STEEL STRUCTURES
708.01 Description
1.a. This work shall consist of furnishing, fabricating, and erecting all bolted or welded steel structures. They shall be fabricated, constructed, and erected in accordance with the det ails shown in the contract and as required by these Specifications.
b.Construction of the steel supe rstructure for a new steel girder bridge is described by the pay item "St eel Superstructure at Station _____".
c.When the Department widens or repairs a bridge with steel components, the work is described by the pay items "Structural Steel for Superstructure and/or Substructure". These pay items are also found on new bridges when steel components are required to complete the construction. However, when these pay items are used, notes are placed in the contract to describe what steel items are to be cons tructed by the pay item "Structural Steel for Superstructure and/or Substructure".
2.The structural steel fabricat ing plants doing work for the NDOT shall be certified under the AISC Quality Certification Program:
a.Category "SBR" certificatio n is required to fabricate main members of Simple Steel Bridge Structures.
b.Category "CBR" certificatio n is required to fabricate main members of Major Steel Bridges (ot her than rolled beam structures).
c.When a fabricator holds eith er a SBR or CBR certificate, a Certified Welding Inspector must be pres ent during all aspect s of fabrication and painting. The Certified Welding Inspector must follow the specified duties for Quality Control accordin g to AWS DW 1.5 Section 6.0.
d.Category "SBD or SBR" cert ification is required to fabricate secondary members.
e.Sole Plate fabrication for Bearing Devices is allowed without AISC certification.
3.a. All welding and weld qualif ication tests shall conform to the provisions of the current ANSI/AASHTO/AWS D1.5 Bridge Welding Code, referred to as AWS Standard Specifications .
b.The Quality Control personn el must be a Certified Welding Inspector and shall be separate from production. The Quality Control personnel shall be present at all times during fabrication and painting. The Quality Control personnel shall be kn owledgeable of the specification requirements to insure that the fabr ication performance is in conformance with the contract and the current AWS D1.5 Bridge Welding Code book.
4.Field Welding shall require a Wel der Qualification Ce rtification. The certification for the welder performing the work shall be submitted to the Engineer three weeks prior to starting t he welding. The welder shall produce his/her credentials and photo ID at the jobsite.
5.Field welding is prohibited unless specifically shown in the contract.
6.Welder Certification: a. All welders, operators, and tackers shall be competent, trained in the particular arc welding process to be used, experienced in the type of
Source: Nebraska Standard Specifications for Highway Construction, 2017 Edition. Pages 555–558 of 1,048.