REINFORCEMENT STEEL

REINFORCEMENT STEEL


PART 1 - GENERAL

1.1      THE REQUIREMENT

A. The Contractor shall furnish, fabricate, and place all concrete reinforcement steel, welded wire fabric, couplers, and concrete inserts for use in reinforced concrete and masonry construction, including all appurtenances such as wires, clips, supports, chairs, spacers, and other accessories, all in accordance with the Contract Documents.

1.2      REFERENCE SPECIFICATIONS, CODES, AND STANDARDS

A.         Comply with the reference specifications of the General Conditions.

B.         Comply with the current provisions of the following Codes and Standards.

1.         American Concrete Institute (ACI)

ACI 315 – Details and Detailing of Concrete Reinforcement

ACI 318 – Building Code Requirements for Structural Concrete

ACI  350  –  Code  Requirements  for  Environmental  Engineering  Concrete
Structures

2.         A 143 - Practice for Safeguarding Against Embrittlement of Hot-Dip Galvanized
Structural Steel Products and Procedure, for Detecting Embrittlement

3.         American Society for Testing and Materials (ASTM)

ASTM A 185 – Specification for Steel Welded Wire Fabric, Plain for Concrete
Reinforcement

ASTM  A 615  –  Specification  for  Deformed  and  Plain  Billet-Steel  Bars  for
Concrete Reinforcement

ASTM A 706 – (weld-able) Specification for Deformed and Plain Billet-Steel Bars for   Concrete   Reinforcement   Grade   60   deformed   with   maximum   carbon equivalent of 0.55.

ASTM  A 767  –  Specification  for  Zinc-Coated  (Galvanized)  Steel  Bars  for
Concrete Reinforcement

4.         American Welding Society (AWS)

AWS D1.4 – Structural Welding Code - Reinforcing Steel

1.3      SUBMITTALS

A.         Submittals shall be made in accordance with the General Conditions.
B.         The following submittals and specific information shall be provided:

1. The Contractor shall furnish shop drawings of all reinforcement steel prior to fabrication in accordance with the Contract Documents.

2. The shop drawings shall include layouts, bending diagrams, assembly diagrams, dimensioned types, locations of all bar laps and splices, placement lists and details  of  bar  reinforcing and  accessories  including  shapes  and dimensions. Layout plans for bar supports and chairs, with typical details, shall be included.

3.         Changes to Reinforcing Steel Contract Drawing Requirements

a. Indicate in separate letter submitted with shop drawings any changes of requirements indicated on the drawings for reinforcing steel.

b. Such changes will not be acceptable unless the Engineer has accepted such changes in writing.

C.         Review of shop drawings by the Engineer will be limited to general compliance with the
Contract Documents.

1.4      DELIVERY, STORAGE, AND HANDLING

A.         Packing and Shipping:  Deliver bars bundled and tagged with identifying tags.

B. Acceptance  at  Site  -  Reinforcing  Bars:     Deliver  reinforcing  bars  lacking  grade identification marks accompanied by manufacturer's guarantee of grade.

1.5      SEQUENCING AND SCHEDULING

A. Bar Supports:  Do not place concrete until the attached data of bar supports has been accepted by the Engineer.

1.6      QUALITY ASSURANCE

A. The Contractor shall make provisions for sampling reinforcing steel delivered to the job site. Two sampling bars, cut from different bars and 3 feet in length for bar sizes #3 through # 5 and 5 feet in length for bars sizes # 6 and larger, shall be taken from each 25 tons or fraction thereof, of each size and heat number delivered to the job site. When the name of the manufacturer, heat identification number, or chemical analysis is not known, the sampling interval shall be each 5 tons or fraction thereof, of each bar size and heat number. The Owner will pay costs of initial tests. Additional testing, due to failure of initial tests, shall be paid for by the Contractor.

B. If reinforcement steel is spliced by welding at any location, the Contractor shall submit certifications of procedure qualifications for each welding procedure used and certification of welder qualifications, for each welding procedure, and for each welder performing the work. Such qualifications shall be as specified in AWS D1.4.

C. The Contractor shall provide samples of each type of welded splice used in the work in a quantity and of dimensions adequate for testing.   At the discretion of the Engineer, radiographic testing of direct butt-welded splices will be performed.  The Contractor shall provide assistance necessary to facilitate testing.  The Contractor shall repair any weld, which fails to meet the requirements of AWS D1.4.   The Owner will pay the costs of
testing; except, the costs of all tests that fail to meet specified requirements shall be paid by the Contractor.

D. The Contractor shall provide to the Resident Project Representative written identification of reinforcement steel by manufacturer's heat number and mill certification, and the fabricator's release number and type from the point of fabrication to the place of final incorporation of the steel into the work.

PART 2 - PRODUCTS

2.1      GENERAL

A. Provide reinforcing steel that is new material, of quality specified, free from excessive rust or scale or any defects affecting its usefulness.

2.2      REINFORCING BARS

A. Reinforcing Bars to be Embedded in Concrete or Masonry:   Grade 60 deformed bars conforming to ASTM A 615 except as specified in the next subparagraph.

B. Reinforcement resisting earthquake-induced flexural and axial forces in concrete frame members  and  in  concrete  wall  boundary  members  shall  comply  with  low  alloy ASTM A 706. ASTM A 615 Grade 60 reinforcement may be used in these members if the following requirements are met:

1. The actual yield strength based on mill tests does not exceed the specified yield strength by more than 18,000 pounds per square inch (retests shall not exceed this value by more than an additional 3,000 pounds per square inch).

2. The ratio of the actual ultimate tensile stress to the actual tensile yield strength is not less than 1.25.

C.         Hot-Dip Galvanized Reinforcing Bars

1. When reinforcing bars are indicated on the drawings to be hot-dip galvanized, perform such galvanizing in accordance with ASTM A 767 and ASTM A 143.

2. Galvanizing: Galvanize bars in conformance with Class 1 coating and perform galvanizing after fabrication and shearing.

D.         Thread Bars

1. Provide   thread   bars   having   continuous   rolled-in   pattern   of   thread-like deformations along entire length.

2. Provide hex nuts and couplers for the thread bars that develop 125 percent of yield strength of bar.

3.         Thread Bars

a.         Conform to ASTM A 615 Grade 60.

b.         Manufacturers: One of the following or equal:
(1) DYWIDAG   Systems   International,   Long   Beach,   California, DYWIDAG Threadbar.

c.          Do not substitute cut threads on regular reinforcing bars for thread bars.

2.3      BAR SUPPORTS

A.         Reinforcement Support Chairs

1. Hot-dip Galvanized Steel:   Provide hot-dip galvanized steel with plastic tips at surfaces which will be exposed to view. Use unless otherwise indicated on the drawings.

2.         Stainless Steel where indicated on the drawings.

B.         Tie Wires: Annealed steel, minimum 16 gage.

C.         Welded Wire Fabric Reinforcement

1.         Welded Wire Fabric:  ASTM A185.

2.         Fabric may be used in place of reinforcing bars if accepted by the Engineer.

3.         Provide fabric in flat sheet form.

4. Provide fabric having cross-sectional area per linear foot of not less than cross- sectional area per linear foot of reinforcing bars indicated on the drawings.

2.4      FABRICATION

A.         All reinforcements shall be shop fabricated:

1.         Cut and bend bars in accordance with provisions of ACI 315 and ACI 318.

2.         Bend bars cold.

3. Provide bars free from defects and kinks and from bends not indicated on the drawings.

2.5      ACCESSORIES

A. Concrete blocks (dobies), used to support and position reinforcement steel, shall have the same or higher compressive strength as specified for the concrete in which it is located.  Where the concrete blocks are used on concrete surfaces exposed to view, the color and texture of the concrete blocks shall match that required for the finished surface. Wire ties shall be embedded in concrete block bar supports.

PART 3 - EXECUTION

3.1      GENERAL

A. Verification of Conditions - Reinforcing Bars: Verify that bars are new stock free from rust scale, loose mill scale, excessive rust, dirt, oil, and other coatings which adversely affect bonding capacity when placed in the work.

3.2      PREPARATION

A.         Surface Preparation

1. Reinforcing Bars:  Thin coating of red rust resulting from short exposure will not be considered objectionable. Thoroughly clean any bars having rust scale, loose mill scale, or thick rust coat.

2. Cleaning of Reinforcement Materials:   Remove concrete or other deleterious coatings from dowels and other projecting bars by wire brushing or sandblasting before bars are embedded in subsequent concrete placement.

3.3      INSTALLATION

A.         Reinforcing Bars

1.         No field bending of bars will be allowed.

2.         Welding

a. Weld reinforcing bars where indicated on the drawings or acceptable to the Engineer.

b.         Perform welding in accordance with AWS D1.4.

B.         Placing Reinforcing Bars
1.         Accurately place bars and adequately secure them in position.

2.         Overlap bars at splices as specified or indicated on the drawings.

3. Unless specifically otherwise indicated on the drawings, install bars at lap splices in contact with each other and fasten bars together with tie wire.

4. If lap splice length for bars in concrete is not specified or indicated on the drawings, bars shall be lap spliced in accordance with ACI 318.

5. If not specified or indicated on the drawings and not specified in Division 4, lap splice bars in masonry in accordance with the California Building Code.

6.         Bar Supports

a. Provide in sufficient number to prevent sagging and to support loads during construction, but in no case less than quantities and at locations as indicated in ACI 315.

b. Support   reinforcing   for   concrete   placed   on   ground   by   standard manufactured chairs, with steel plates for resting on ground.

c. Do not use brick, broken concrete masonry units, spalls, rocks, or similar material for supporting reinforcing steel.

7. If not indicated on the drawings, provide protective concrete cover in accordance with ACI 318.

C.         Tying of Bar Reinforcement

1.         Fasten bars securely in place with wire ties.

2.         Tie bars sufficiently often to prevent shifting.

3. There shall be at least 3 ties in each bar length (does not apply to dowel lap splices or to bars shorter than 4 feet, unless necessary for rigidity).

4.         Tie slab bars at every intersection around periphery of slab.

5. Tie wall bars and slab bar intersections other than around periphery at not less than every fourth intersection, but at not greater than following maximum spacings:




Bar Size Slab Bars
Spacing
(Inches) Wall Bars
Spacing
(Inches)  
Bars Number 5 and Smaller 60 48  
Bars Number 6 through Number 9 96 60  
Bars Number 10 and Number 11 120 96

6. After tying wire ties, bend ends of wire ties in towards the center of the concrete section. Wire ties shall conform to the cover requirements of the reinforcing bars.

7.         Above tying requirements do not apply to reinforcement for masonry.  Refer to DIVISION 4 for tying requirements for masonry.

D.         Lap Splices of Reinforcing Bars
1. Where bars are to be lapped spliced at joints in concrete, ensure bars project from concrete first placed, minimum length equal to lap splice length indicated on the drawings.

2. Where lap splice length is not indicated on the drawings, then provide lap splice length as specified in ACI 318 and this Division.

E.         Welded Wire Fabric Reinforcement

1. Install necessary wiring, spacing chairs, or supports to keep welded wire fabric in place while concrete is being placed.

2.     Bend fabric as indicated on the drawings or required to fit work.

3. Unroll or otherwise straighten fabric to make perfectly flat sheet before placing in the work.

4.     Lap splice welded wire fabric as indicated on the drawings.

5. If lap splice length is not indicated on the drawings, splice fabric in accordance with ACI 318.

END OF SECTION