1、Designation: A970/A970M 16A970/A970M 17Standard Specification forHeaded Steel Bars for Concrete Reinforcement1This standard is issued under the fixed designation A970/A970M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the year
2、of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification covers deformed steel reinforcing bars in cut lengths, with a head attached to one or both ends
3、, forconcrete reinforcement. Heads are forge-formed, machined from bar stock, or cut from plate. Attachment can be accomplishedthrough:1.1.1 Welding;1.1.2 Integrally hot forging of a head from the reinforcing bar end;1.1.3 Internal threads in the head mating to threads on the bar end;1.1.4 Cold-swag
4、ing an externally threaded coupling sleeve onto the reinforcing bar;1.1.5 Cold-extruding an external coupling sleeve onto the reinforcing bar;1.1.6 Cold-swaging an external coupling sleeve or headed sleeve onto the reinforcing bar;1.1.7 Attaching a coupling sleeve to the end of the reinforcing bar b
5、y means of the means of a ferrous-filler medium; or1.1.8 Separate threaded nut to secure the head to the bar.NOTE 1The requirements of this specification are only applicable to headed bars where the attachment of the head is accomplished by one of themethods listed in 1.1.1.2 Limitations on head dim
6、ensions and on obstructions and interruptions of bar deformations on the non-planar features on thebearing face of the head are presented in Annex A1. The requirements in Annex A1 only apply when specified by the purchaser(see 4.2.3).1.3 This specification is applicable for orders in either inch-pou
7、nd units as Specification A970 or SI units as SpecificationA970M.1.4 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI unitsare shown in brackets. The values stated in each system may not be exact equivalents; therefore, each
8、system shall be usedindependently of the other. Combining values from the two systems may result in non-conformance with the specification.1.5 This specificationstandard does not purport to address all of the safety concerns, if any, associated with its use. It is theresponsibility of the user of th
9、is standard to establish appropriate safety safety, health, and healthenvironmental practices anddetermine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in
10、the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2A370 Test Methods and Definitions for Mechanical Testing of Steel Product
11、sA615/A615M Specification for Deformed and Plain Carbon-Steel Bars for Concrete ReinforcementA700 Guide for Packaging, Marking, and Loading Methods for Steel Products for ShipmentA706/A706M Specification for Deformed and Plain Low-Alloy Steel Bars for Concrete Reinforcement1 This specification is un
12、der the jurisdiction ofASTM Committee A01 on Steel, Stainless Steel and RelatedAlloys and is the direct responsibility of Subcommittee A01.05on Steel Reinforcement.Current edition approved March 1, 2016Nov. 15, 2017. Published March 2016November 2017. Originally approved in 1997. Last previous editi
13、on approved in 20152016as A970/A970M 15A970/A970M 16.1. DOI: 10.1520/A0970_A0970M-16.10.1520/A0970_A0970M-17.2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM customer service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the s
14、tandards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accur
15、ately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor
16、Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12.2 AWS Standards:3AWS C6.1 Recommended Practices for Friction WeldingAWS D1.4D1.4M Structural Welding Code - Reinforcing Steel2.3 U.S. Military Standard:4MIL-STD-129 Marking for Shipment and Storage2.4 U.S. Federal Standard:4Fed. S
17、td. No. 123 Marking for Shipment (Civil Agencies)2.5 ACI Standard:5ACI 318 Building Code Requirements for Structural Concrete3. Terminology3.1 Definitions of Terms Specific to This Specification:3.1.1 cold-extruded coupling sleeve headed bar, nsteel reinforcing bar that has the head(s) attached by m
18、eans of a couplingsleeve that is axially cold- extruded onto the bar end(s).3.1.1.1 DiscussionSimilar to cold-swaged threaded coupling sleeve headed bar. This extruded coupling sleeve consists of an axially extruded sleeveportion that engages the deformed reinforcing bar and a pre-threaded integral
19、stud with external threads, which match threadsinternal to the head(s). The head is screwed onto the mating threads on the extruded coupling sleeve. The threads may be parallelor tapered.3.1.2 cold-swaged external sleeve headed bar, nsteel reinforcing bar that has the head(s) attached by means of a
20、couplingsleeve that is cold-swaged onto the bar end(s).3.1.2.1 DiscussionSimilar to cold-swaged threaded coupling sleeve headed bar. This sleeve is a combination of a tubular sleeve portion extendingin front of the head, and an integral one-piece head immediately adjacent to the cold-swaged sleeve.
21、The sleeve and head assemblyis attached to the deformed reinforcing bar by cold-swaging the tubular sleeve portion to the bar with multiple crimps from ahydraulic swaging tool and die, up to the face of the head section.3.1.3 cold-swaged headed sleeve headed bar, nsteel reinforcing bar that has the
22、head(s) attached by means of a sleeve thatis cold-swaged onto the bar end(s).3.1.3.1 DiscussionSimilar to cold-swaged external coupling sleeve headed bar. This sleeve is a one-piece unit with an integral cold-swaged head. Thehead assembly is attached to the deformed reinforcing bar by cold-swaging t
23、he tubular sleeve to the bar with a hydraulic swagingtool and die.3.1.4 cold-swaged threaded coupling sleeve headed bar, nsteel reinforcing bar that has the head(s) attached by means of acoupling sleeve that is cold-swaged onto the bar end(s).3.1.4.1 DiscussionThe coupling sleeve assembly is attache
24、d to the deformed reinforcing bar by cold-swaging the tubular sleeve portion to the barwith multiple crimps from a hydraulic swaging tool and die, up to the face of the pre-threaded section. This coupling sleeve ispre-threaded with external threads, which match threads internal to the head(s). The h
25、ead is screwed onto the mating threads onthe coupling sleeve. The threads may be parallel or tapered.3.1.5 ferrous-filler coupling sleeve headed bar, nsteel reinforcing bar that has the head(s) attached by means of a couplingsleeve mechanically attached to the bar via an interlock of ferrous-filler
26、material and the bar deformations.3.1.5.1 Discussion3 Available from American Welding Society (AWS), 550 NW LeJeune Rd., Miami, FL 33126, http:/www.aws.org.4 Available from Standardization Documents Order Desk, Bldg. 4 Section D, DLA Document Services, Building 4/D, 700 Robbins Ave., Philadelphia, P
27、A 19111-5094,Attn: NPODS. Or visit: http:/assist.daps.dla.mil/online. http:/quicksearch.dla.mil.5 Available from American Concrete Institute (ACI), P.O. Box 9094, Farmington Hills, MI 48333-9094, http:/www.concrete.org.A970/A970M 172The ferrous-filler material is cast into the coupling sleeve. A var
28、iation includes a separate internally threaded nut secured to thethreaded bar end or attached via welding a plate to the end of a prepared coupling sleeve.3.1.6 forged headed bar, nsteel reinforcing bar that has the head(s) integrally forged.3.1.7 head, nround, elliptical, or rectangular shape used
29、to anchor a steel reinforcing bar in concrete.3.1.8 net bearing area, ngross cross-sectional area of the head minus the nominal cross-sectional area of the deformedreinforcing bar.3.1.9 threaded headed bar, nsteel reinforcing bar that has the head(s) attached using tapered or straight threads intern
30、al to thehead or by a separate internally threaded nut securing the head to the threaded bar end.3.1.10 welded headed bar, nsteel reinforcing bar that has the head(s) welded.4. Ordering Information4.1 Orders for headed steel bars for concrete reinforcement under this specification shall contain foll
31、owing information:4.1.1 Quantity;4.1.2 Type of product: welded, forged, cold-swaged, cold-extruded, ferrous metal-filled sleeved, or threaded headed bars;4.1.3 Reinforcing bar specification and year of issue;4.1.4 Bar size designation;4.1.5 Deformed reinforcing bars;4.1.6 Head geometry, including th
32、ickness, diameter or height and width of the head;4.1.7 Number of heads per bar length;4.1.8 Length of bar assembly; and4.1.9 ASTM designation and year of issue.4.2 The purchaser shall have the option to specify additional requirements, including, but not limited to, the following:4.2.1 Packaging (1
33、5.1, 15.2);4.2.2 Bend testing of welded headed bars in sizes No. 11, 14, and 18 36, 43, and 57 (6.4.1);4.2.3 Optional requirements of Annex A1, if applicable;4.2.4 Optional copy of material test report (6.1, 13.2); and4.2.5 Other special requirements, if any.5. Material and Manufacture5.1 Reinforcin
34、g BarsFor welded headed bars, the reinforcing bars shall conform to Specification A706/A706M. For forgednon-welded headed bars, the reinforcing bars shall conform to Specification A615/A615M or A706/A706M, as specified by thepurchaser.5.2 Heads:5.2.1 The head material shall be selected by the manufa
35、cturer.5.3 The head dimensions shall be provided by the purchaser in the order. Head dimensions shall define the head geometryincluding thickness, diameter, or height and width of the head (Fig. 1). Alternate head dimensions supplied by the manufacturershall be permitted if agreed to in advance by t
36、he purchaser. The manufacturer shall furnish documentation to the purchaser, in theform of calculations or test reports, or both, that confirms the suitability of alternate head dimensions for the intended application.FIG. 1 Headed Reinforcing BarA970/A970M 173NOTE 2Alternate head dimensions resulti
37、ng in a net bearing area less than four times the nominal cross-sectional area of the deformed reinforcingbar are not suitable for use in construction projects governed by certain consensus building codes and design standards (see 5.4 and Note 3).5.4 When specified by the purchaser in the purchase o
38、rder or contract as a class HA headed bar, head dimensions shall meetthe requirements of Annex A1.NOTE 3Some methods of attachment, as defined in Section 3 of this specification, do not meet the requirements on obstructions as prescribed inAnnexA1. The requirements for head dimensions, limitations t
39、o reinforcing bar deformation interruptions and the size of obstruction allowances providedin AnnexA1 are mandated by certain consensus building codes and design standards, for example, “Building Code Requirements for Structural Concrete(ACI 318).“ Heads with obstructions that do not conform to Anne
40、xA1 may not be permitted for use by certain building codes and design standards, suchas ACI 318.5.5 WeldingA welding procedure conforming to AWS D1.4D1.4M shall be used for all required production welding of thehead to the bar, except for friction welding that shall conform to AWS C6.1 in conjunctio
41、n with the manufacturers QA/QCprocedures.5.6 ForgingFor integrally forged headed bars, the heads shall be produced by deforming the bar ends in a hot-forging process.5.7 Threading:5.7.1 Threads on bars shall be either tapered or straight. The head shall either thread onto the bar directly, or it sha
42、ll be heldon the bar end by a nut and counternut. Thread specifications and standards shall be selected by the manufacturer.5.7.2 The out-of-roundness in the as-rolled reinforcing bar shall be evaluated so that the manufacturers minimum threaddimensions are maintained.5.7.3 It shall be permissible t
43、o hot- or cold-roll, or machine cut, threads into the surface of the bar and heads at the option ofthe manufacturer.6. Mechanical Test and Performance Requirements6.1 Headed bars shall be subjected to mechanical tests to verify production method and product quality prior to manufacture.Mechanical te
44、sting also shall be performed at intervals during production of the assembly.A970/A970M 1746.2 Tensile Tests:6.2.1 Tensile testing of the headed bar assembly shall be performed in accordance with the requirements described in TestMethods and Definitions A370. The failure mode shall be reported as pa
45、rtial or total fracture of the bar, the head, or the head-to-barconnection.6.2.2 Specimen PreparationTensile test specimens shall be the full cross-section of the bar with a head attached to one endof the reinforcing bar. The minimum length of the test specimen shall be the greater of 10 in. 250 mm
46、or ten times the nominaldiameter of the bar. The test specimen shall be placed in the testing machine with the head supported to prevent movement andbending of the head. Provisions shall be made for clearance between the support and any weld or forming material on thereinforcing bar-to-head connecti
47、on. The opposite bar end of the bar, without a head attached, shall be gripped by the testingmachine and loaded to failure.6.3 Tensile Requirements:6.3.1 Tensile PropertiesThe tensile properties of the test specimen shall conform to one of the following classes:6.3.1.1 Class ADevelop the minimum spe
48、cified tensile strength of the reinforcing bar.6.3.1.2 Class BDevelop the minimum specified tensile strength and the minimum specified elongation of the reinforcing bar.NOTE 4Reference the requirements of Specifications A615/A615M and A706/A706M for minimum reinforcing bar tensile properties. Class
49、A hasbeen introduced for applications that require the development of the minimum tensile strength of the reinforcing bar. The Class B criteria requires thehead and the head-to-bar connection to meet or exceed the minimum specified tensile strength and the minimum specified elongation requirements ofthe reinforcing bar. In the previous criteria, the failure of the head or the head-to-bar connection within the attachment region was cause for rejection.6.4 Bend Test Requirements:6.4.1 Only welded headed bars in sizes No. 3 to 10 10 to 32
