03 20 01.00 10 CONCRETE REINFORCEMENT.doc

SECTION 03 20 01.00 10

CONCRETE REINFORCEMENT

PART 1 GENERAL

1.1 REFERENCES

1.1.1 The publications listed below form a part of this specification to the extent referenced. The publications are referred to in the text by the basic designation only. Unless otherwise noted, the latest published version and/or revision shall be used.

1.1.1.1 ACI INTERNATIONAL (ACI)

a. ACI 301 Specifications for Structural Concrete

b. ACI 318/318R Building Code Requirements for Structural Concrete and Commentary

c. ACI SP-66 ACI Detailing Manual

1.1.1.2 AMERICAN WELDING SOCIETY (AWS)

a. AWS D1.4 Structural Welding Code - Reinforcing Steel

1.1.1.3 ASTM INTERNATIONAL (ASTM)

a. ASTM A 82 Standard Specification for Steel Wire, Plain, for Concrete Reinforcement

b. ASTM A 184 Standard Specification for Welded Deformed Steel Bar Mats for Concrete Reinforcement

c. ASTM A 185 Standard Specification for Steel Welded Wire Reinforcement, Plain, for Concrete

d. ASTM A 370 Standard Test Methods and Definitions for Mechanical Testing of Steel Products

e. ASTM A 497 Standard Specification for Steel Welded Wire Reinforcement, Deformed, for Concrete

f. ASTM A 615 Standard Specification for Deformed and Plain Billet-Steel Bars for Concrete Reinforcement

g. ASTM A 706 Standard Specification for Low-Alloy Steel Deformed and Plain Bars for Concrete Reinforcement

h. ASTM A 767 Standard Specification for Zinc-Coated (Galvanized) Steel Bars for Concrete Reinforcement

i. ASTM A 775 Standard Specification for Epoxy-Coated Steel Reinforcing Bars

j. ASTM A 82 Standard Specification for Steel Wire, Plain, for Concrete Reinforcement

k. ASTM A 884 Standard Specification for Epoxy-Coated Steel Wire and Welded Wire Reinforcement

l. ASTM C 1116 Standard Specification for Fiber-Reinforced Concrete and Shotcrete

m. ASTM E 94 Standard Guide for Radiographic Examination

1.1.1.4 CONCRETE REINFORCING STEEL INSTITUTE (CRSI)

a. CRSI 1MSP Manual of Standard Practice

1.2 SUBMITTALS

1.2.1 Government approval may be required on any of the following items. Items requiring submittals will be listed on the AF Form 66. Provide copies of all submittals per the requirements in Section 01 33 00, Submittal Procedures, or as listed on the AF Form 66.

1.2.1.1 SD-02 Shop Drawings

a. Reinforcement

(1) The Contractor shall submit shop drawings which include: reinforcement steel placement drawings; reinforcement steel schedules showing quantity, size, shape, dimensions, weight per foot, total weights and bending details; and details of bar supports showing types, sizes, spacing and sequence.

1.2.1.2 SD-03 Product Data

a. Welding. Welding of reinforcing should not be required to complete the project. However, if it becomes required, the contractor shall submit project data related to the required welding.

(1) A list of qualified welders names with copies of welding certificates.

b. Butt-Splice Welding

(1) Submit proposed procedure for butt-splicing steel bars prior to making the test butt-splices for qualification of the procedure. Properties and analyses of steel bars and splicing materials shall be included in the submitted procedure. Physical properties of splicing sleeves shall include length, inside and outside diameters, and inside surface details.

1.2.1.3 Samples

a. Epoxy-Coated Bars

(1) Sample of coating material and 1.5 pounds of patching material shall be submitted with the delivery of the bars.

1.2.1.4 SD-06 Test Reports

a. Tests, Inspections, and Verifications

(1) Mechanical butt-splices: Submit test reports or verification that proposed mechanical butt-splice devices develop the specified strength of the spliced reinforcing bar.

(2) Certified tests reports of reinforcement steel used in welded applications showing the steel complies with the applicable specifications shall be furnished for each steel shipment and identified with specific lots prior to placement. Three copies of the heat analyses shall be provided for each lot of steel furnished and the Contractor shall certify that the steel conforms to the heat analyses.

1.2.1.5 SD-07 Certificates

a. Epoxy-Coated Steel Bars

(1) Written certification for coating material and coated bars shall be submitted with the delivery of the bars.

b. Qualification of Welders

(1) Certificates on the Qualifications of welders performing Steel Bar Butt-Splices shall be submitted prior to commencing butt-splicing.

1.3 WELDING

1.3.1 Welders shall be qualified in accordance with AWS D1.4. Qualification test shall be performed at the worksite and the Contractor shall notify the Contracting Officer 24 hours prior to conducting tests. Special welding procedures and welders qualified by others may be accepted as permitted by AWS D1.4.

1.4 DELIVERY AND STORAGE

1.4.1 Reinforcement and accessories shall be stored off the ground on platforms, skids, or other supports.

PART 2 PRODUCTS

2.1 MATERIALS

2.1.1 Materials shall conform to the following requirements.

2.1.1.1 Steel Bars

a. Steel bars shall comply with the requirements of ASTM A 615 or ASTM A 706, deformed, of the grades, sizes and lengths shown. Reinforcing bars shall be Grade 60 unless noted otherwise. If the Grade 40 bars shown are unavailable the Contractor may substitute Grade 60 bars of the same size and spacing as indicated for Grade 40 bars when authorized. Cold drawn wire used for spiral reinforcement shall conform to ASTM A 82.

b. In highly corrosive environments, or when directed by the Contracting Officer, reinforcing steel shall be zinc-coated (galvanized) or epoxy-coated as appropriate.

2.1.1.2 Zinc-Coated (Galvanized) Bars

a. Zinc-coated (galvanized) bars shall comply with the requirements of ASTM A 767, Class II (2.0 oz. zinc psf), hot-dip galvanized after fabrication.

2.1.1.3 Epoxy-Coated Bars

a. Epoxy-coated steel bars shall comply with the requirements of ASTM A 775, including written certifications for coating material and coated bars, sample of coating material, and 0.5 pounds of patching material.

2.1.1.4 Mechanical Butt-Splices

a. Mechanical reinforcing bar butt-splicing devices shall be an approved exothermic, threaded coupling, swaged sleeve or other positive connecting type. The splicing device shall be capable of developing the 125 percent of the specified minimum ultimate tensile strength of the smallest bar of the splice, and, the additional deformation of number 14 and smaller bars due to slippage or other movement within the splice sleeve shall not exceed 0.015 inches (unit strain 0.0015 inches/inch) beyond the elongation of an unspliced bar based upon a 10 inch gage length spanning the extremities of the sleeve at a stress of 30,000 psi. The additional deformation of number 18 bars shall not exceed 0.03 inches (unit strain 0.003 inches/inch) beyond the elongation of an unspliced bar based upon a 10 inch gage length spanning the extremities of the sleeve at a stress of 30,000 psi. The amount of the additional deformation shall be determined from the stress-strain curves of the unspliced and spliced bars tested as required paragraph QUALIFICATION OF BUTT-SPLICING PROCEDURE for qualification of the butt-splicing procedure.

2.1.1.5 Fabricated Bar Mats

a. Fabricated bar mats shall comply with the requirements of ASTM A 184, clipped or welded mats, bar sizes and spacing as shown.

2.1.1.6 Steel Welded Wire Fabric

a. Steel welded wire fabric shall comply with the requirements of ASTM A 185 or ASTM A 497 wire sizes and spacing as shown.

b. In highly corrosive environments, or when directed by the Contracting Officer, welded wire fabric shall be epoxy-coated conforming to ASTM A 884.

2.1.2 Accessories

2.1.2.1 Bar Supports

a. Bar supports shall comply with the requirements of ACI 301. Where concrete formed surfaces will be exposed to view or weather or will be painted, steel supports within 1/2 inch of concrete surface shall be galvanized, plastic protected or of stainless steel. For slabs on grade or foundation elements poured over grade, supports shall be precast concrete blocks, plastic coated steel fabricated with bearing plates or specially designed wire-fabric supports fabricated of plastic. Precast concrete supports shall be wedged-shaped, not larger than 3-1/2 by 3-1/2 inches, of thickness equal to that indicated for concrete cover, have an embedded hooked tie-wire for anchorage and have a compressive strength equal to that of the surrounding concrete.

2.1.2.2 Wire Ties

a. Wire ties shall be 16 gage or heavier black annealed wire. Ties for epoxy-coated bars shall be vinyl-coated or epoxy-coated. Ties for zinc-coated bars shall be zinc-coated.

2.2 SYNTHETIC FIBER REINFORCEMENT

2.2.1 Synthetic fiber shall be polypropylene with a denier less than 100 and a nominal fiber length of 2 inches.

2.3 TESTS, INSPECTIONS AND VERIFICATIONS

2.3.1 The Contractor shall have material tests required by applicable standards and specified performed by an approved laboratory and certified to demonstrate that the materials are in conformance with the specifications. Tests, inspections, and verifications shall be performed and certified at the Contractor's expense.

2.3.1.1 Qualification of Welders

a. Qualification of welders performing steel bar butt-splices shall be certified to have satisfactorily completed a course of instruction in the proposed method of butt-splicing or have satisfactorily performed such work within the preceding year.

2.3.1.2 Qualification of Butt-Splicing Procedure

a. As a condition of approval of the butt-splicing procedure, the Contractor, in the presence of the Contracting Officer, shall make three test butt-splices of steel bars of each size to be spliced using the proposed butt-splicing method. These test butt-splices and unspliced bars of the same size shall be tension tested to destruction with stress-strain curves plotted for each test. Test results must show that the butt-splices meet the specified strength and deformation requirements in order for the splicing procedure to be approved.

2.3.1.3 Radiographic Examination of Welds

a. Radiographic examination of welds shall be in accordance with ASTM E 94 and shall be performed and evaluated by an approved testing agency adequately equipped to perform such services. Radiographs of welds and evaluations of the radiographs submitted for approval shall become the property of the Government.

PART 3 EXECUTION

3.1 REINFORCEMENT

3.1.1 Reinforcement shall be fabricated to shapes and dimensions shown on the approved shop drawings in conformance with the requirements of ACI 318/318R. Reinforcement shall be cold bent unless otherwise authorized. All bending of epoxy and zinc-coated reinforcing shall be performed prior to coating and shall be accomplished at the mill. Uncoated reinforcing shall be bent at the mill unless authorized by the Contracting Officer to be performed in the field. Bars shall not be bent after embedment in concrete. Safety caps shall be placed on all exposed ends of vertical concrete reinforcement bars that pose a danger to life safety. Wire tie ends shall face away from the forms.

Reinforcement shall be free from loose rust and scale, dirt, oil, or other deleterious coating that could reduce bond with the concrete.

3.1.1.1 Welding

a. Welding of reinforcing steel will be permitted only where indicated or authorized. Contractor shall receive and have present a current burn permit for all welding. Welding shall be in accordance with AWS D1.4 except where otherwise specified or indicated.

3.1.1.2 Placement

a. Reinforcement shall be placed and supported in accordance with ACI 318/318R at locations shown on the shop drawings. Reinforcement shall not be continuous through expansion joints and shall be as indicated through construction or contraction joints. Concrete coverage shall be as indicated or as required by ACI 318/318R. The spacing between adjacent bars and the distance between layers of bars may not vary from the indicated position by more than one bar diameter nor more than 1 inch.

b. If bars are moved more than one bar diameter to avoid interference with other reinforcement, conduits or embedded items, the resulting arrangement of bars, including additional bars required to meet structural requirements, shall be approved before concrete is placed.

3.1.1.3 Splicing

a. Splices of reinforcement shall conform to ACI 318 and shall be made only as required or as indicated. Bars may be spliced at alternate or additional locations at no additional cost to the Government subject to approval.

b. Lap splices shall be used only for bars smaller than size 14. Lapped bars shall be placed in contact and securely tied or spaced transversely apart to permit the embedment of the entire surface of each bar in concrete. Lapped bars shall not be spaced farther apart than 1/5 the required length of lap or 6 inches.

c. Butt-splices shall be used only for splicing size 14 and 18 bars and for splicing #11 bars to larger bars except where otherwise shown or authorized. Butt splices can be welded or mechanical splices. Bars shall be cleaned of all oil, grease, dirt, rust, scale and other foreign substances and shall be flame dried before splicing. Adequate jigs and clamps or other devices shall be provided to support, align and hold the longitudinal centerline of the bars to be butt-spliced in a straight line. Butt-splices shall be as follows:

(1) Welded butt-splices shall be performed in accordance with the approved procedure unless otherwise authorized by the Contracting Officer and shall be full penetration butt welds. Bars used in welded splices shall be restricted to steel shown by heat analysis to have a sulfur content not exceeding 0.05 percent. The ends of bars to be welded shall be prepared in accordance with the approved butt-welding procedure. Tension splices of number 14 or smaller bar shall be staggered longitudinally a minimum of 5 feet or as otherwise indicated so that no more than half of the bars are spliced at any one section. Tension splices of number 18 bars shall be staggered longitudinally a minimum of 5 feet so that no more than 1/3 of the bars are spliced at any one section.

(2) Mechanical Splices: Bars to be spliced by a mechanical butt-splicing process may be sawed, sheared or flame cut provided the ends of sheared bars are reshaped after shearing and all slag is removed from the ends of flame cut bars by chipping and wire brushing prior to splicing. Surfaces to be enclosed within a splice sleeve or coupling shall be cleaned by wire brushing or other approved method prior to splicing. Splices shall be made using manufacturer's standard jigs, clamps, ignition devices and other required accessories. Tension splices of number 14 or smaller bar shall be staggered longitudinally a minimum of 5 feet or as otherwise indicated so that no more than half of the bars are spliced at any one section. Tension splices of number 18 bars shall be staggered longitudinally a minimum of 5 feet so that no more than 1/3 of the bars are spliced at any one section.

3.1.2 Concrete cover to reinforcement shall be in accordance with ACI 318 unless shown otherwise on the drawings with the following tolerances for minimum cover:

MINIMUM COVER

VARIATION

6 inch plus 1/2 inch

4 inch plus 3/8 inch

3 inch plus 3/8 inch

2 inch plus 1/4 inch

1-1/2 inch plus 1/4 inch

1 inch plus 1/8 inch

3/4 inch plus 1/8 inch

3.2 WELDED-WIRE FABRIC PLACEMENT

3.2.1 Welded-wire fabric shall be placed in slabs as indicated. Fabric placed in slabs on grade shall be continuous between expansion, construction, and contraction joints. Fabric placement at joints shall be as indicated.

3.2.2 Lap splices shall be made in such a way that the overlapped area equals the distance between the outermost crosswires plus 2 inches. Laps shall be staggered to avoid continuous laps in either direction. Fabric shall be wired or clipped together at laps at intervals not to exceed 4 feet. Fabric shall be positioned by the use of supports.

3.3 DOWEL INSTALLATION FOR SLABS ON GRADE

3.3.1 Dowels shall be installed in slabs on grade at locations indicated and at right angles to joint being doweled. Dowels shall be accurately positioned and aligned parallel to the finished concrete surface before concrete placement. Dowels shall be rigidly supported during concrete placement. One end of dowels shall be coated with a bond breaker.

3.4 SYNTHETIC FIBER REINFORCED CONCRETE

3.4.1 Fiber reinforcement shall be added to the concrete mix in accordance with the applicable sections of ASTM C 1116 and the recommendations of the manufacturer, at a minimum amount of 3.5 lbs. per cubic yard of concrete.

3.5 FIELD TESTS AND INSPECTIONS

3.5.1 Reinforcement

3.5.1.1 Concrete reinforcing shall be inspected prior to closing of concrete formwork or placing of concrete. Inspect all reinforcing for conformance to Contract requirements. Written reports shall be submitted of all inspections on a daily basis. Such reports shall include a description of each area inspected, deficiencies noted, and corrective action undertaken to resolve such deficiencies. Deficiencies observed shall immediately be brought to the attention of the Contractor's Field Superintendent and Reinforcing Placer's Foreman.

3.5.1.2 Butt-splices: All butt-splices shall be marked in the field and shall identify the splicer who performed the work.

a. The contractor shall perform the following during the butt-splicing operations as specified and as directed:

(1) Visual Examination - All welded splices shall be visually examined for the presence of cracks, undercuts, inadequate size and other visible defects. Respliced connections resulting from correction of visual defects may be radiographically examined at the option of the Contracting Officer as specified in paragraph SUPPLEMENTAL EXAMINATION. Mechanical butt-splices shall be visually examined to determine if the splice has been correctly completed according to the manufacturer’s directions.

(2) Tension Tests - Tension tests to 90 percent of the minimum specified ultimate tensile strength of the spliced bars or to destruction shall be performed on one test specimen made in the field for every 25 welded splices made. Test specimens shall be made by the splicers engaged in the work, using the approved splicing procedure and the same size bars placed in the same relative position, and under the same conditions as those in the groups represented by the specimens. Stress-strain curves shall be furnished for each butt-splice tested.

(3) Radiographic Examination - Not less than one of each 25 welded splices selected at random by the Contracting Officer shall be examined radiographically and evaluated for defects. The greatest dimension of any porosity (gas pocket or similar void) or fusion-type defect (slag inclusion, incomplete fusion or similar generally elongated defect in weld fusion) shall not exceed 1/4 inch. The minimum clearance between edges of porosity or fusion-type defects shall not be less than 1 inch.

(4) Correction of Deficiencies - No splice shall be embedded in concrete until satisfactory results of visual examination and the required tests or examinations have been obtained. All splices having visible defects or represented by test specimens which do not satisfy the tests or examinations shall be removed. If any of the tension test specimens fail to meet the strength requirements or deformation limitations two production splices from the same lot represented by the test specimens which failed shall be cut out and tension tested by the Contractor. If both of the retests pass the strength requirements and deformation limitations all of the splices in the lot will be accepted. If one or both of the retests fail to meet the strength requirements or deformation limitations all of the splices in the lot will be rejected. All costs of removal, testing and resplicing of the additional production splices shall be borne by the Contractor. The bars of rejected splices shall be cut off outside the splice zone of weld metal, filler metal contact, coupling or sleeve. The cut ends shall be finished as specified and the joints shall be respliced and reinspected at no additional cost.

(5) Supplemental Examination - The Contracting Officer may require additional or supplemental radiographic examination and/or tension test of any completed splice.

END OF SECTION 03 20 01.00 10

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