1、Designation: A970/A970M 16Standard 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 of last revis
2、ion. 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 reinforcingbars in cut lengths, with a head attached to one or both ends, forconcrete
3、reinforcement. Heads are forge-formed, machinedfrom bar stock, or cut from plate. Attachment can be accom-plished through:1.1.1 Welding;1.1.2 Integrally hot forging of a head from the reinforcingbar end;1.1.3 Internal threads in the head mating to threads on thebar end;1.1.4 Cold-swaging an external
4、ly threaded coupling sleeveonto the reinforcing bar;1.1.5 Cold-extruding an external coupling sleeve onto thereinforcing bar;1.1.6 Cold-swaging an external coupling sleeve or headedsleeve onto the reinforcing bar;1.1.7 Attaching a coupling sleeve to the end of the reinforc-ing bar by means of the me
5、ans 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 toheaded bars where the attachment of the head is accomplished by one ofthe methods listed in 1.1.1.2 Limitations on head dimensions and on obs
6、tructions andinterruptions of bar deformations on the non-planar features onthe bearing face of the head are presented in Annex A1. Therequirements in Annex A1 only apply when specified by thepurchaser (see 4.2.3).1.3 This specification is applicable for orders in eitherinch-pound units as Specifica
7、tion A970 or SI units as Specifi-cation A970M.1.4 The values stated in either inch-pound units or SI unitsare to be regarded separately as standard. Within the text, theSI units are shown in brackets. The values stated in eachsystem may not be exact equivalents; therefore, each systemshall be used i
8、ndependently of the other. Combining valuesfrom the two systems may result in non-conformance with thespecification.1.5 This specification does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-p
9、riate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA615/A615M Specification for Deformed and Plain Carbon-Steel Bars for Concrete
10、 ReinforcementA700 Guide for Packaging, Marking, and Loading Methodsfor Steel Products for ShipmentA706/A706M Specification for Deformed and Plain Low-Alloy Steel Bars for Concrete Reinforcement2.2 AWS Standards:3AWS C6.1 Recommended Practices for Friction WeldingAWS D1.4 D1.4M Structural Welding Co
11、de - ReinforcingSteel2.3 U.S. Military Standard:4MIL-STD-129 Marking for Shipment and Storage2.4 U.S. Federal Standard:4Fed. Std. No. 123 Marking for Shipment (Civil Agencies)2.5 ACI Standard:5ACI 318 Building Code Requirements for Structural Con-crete3. Terminology3.1 Definitions of Terms Specific
12、to This Specification:1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.05 on Steel Reinforcement.Current edition approved March 1, 2016. Published March 2016. Originallyapproved in 1997
13、. Last previous edition approved in 2015 as A970/A970M 151.DOI: 10.1520/A0970_A0970M-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM customer service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summa
14、ry page onthe ASTM website.3Available from American Welding Society (AWS), 550 NW LeJeune Rd.,Miami, FL 33126, http:/www.aws.org.4Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS. Or visit: http:/assist.daps.dla.mil/onl
15、ine.5Available from American Concrete Institute (ACI), P.O. Box 9094, FarmingtonHills, MI 48333-9094, http:/www.concrete.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United Sta
16、tes13.1.1 cold-extruded coupling sleeve headed bar, nsteelreinforcing bar that has the head(s) attached by means of acoupling sleeve that is axially cold- extruded onto the barend(s).3.1.1.1 DiscussionSimilar to cold-swaged threaded cou-pling sleeve headed bar. This extruded coupling sleeve consists
17、of an axially extruded sleeve portion that engages the deformedreinforcing bar and a pre-threaded integral stud with externalthreads, which match threads internal to the head(s). The headis screwed onto the mating threads on the extruded couplingsleeve. The threads may be parallel or tapered.3.1.2 c
18、old-swaged external sleeve headed bar, nsteel re-inforcing bar that has the head(s) attached by means of acoupling sleeve that is cold-swaged onto the bar end(s).3.1.2.1 DiscussionSimilar to cold-swaged threaded cou-pling sleeve headed bar. This sleeve is a combination of atubular sleeve portion ext
19、ending in front of the head, and anintegral one-piece head immediately adjacent to the cold-swaged sleeve. The sleeve and head assembly is attached to thedeformed reinforcing bar by cold-swaging the tubular sleeveportion to the bar with multiple crimps from a hydraulicswaging tool and die, up to the
20、 face of the head section.3.1.3 cold-swaged headed sleeve headed bar, nsteel rein-forcing bar that has the head(s) attached by means of a sleevethat is cold-swaged onto the bar end(s).3.1.3.1 DiscussionSimilar to cold-swaged external cou-pling sleeve headed bar. This sleeve is a one-piece unit with
21、anintegral cold-swaged head. The head assembly is attached tothe deformed reinforcing bar by cold-swaging the tubularsleeve to the bar with a hydraulic swaging tool and die.3.1.4 cold-swaged threaded coupling sleeve headed bar,nsteel reinforcing bar that has the head(s) attached by meansof a couplin
22、g sleeve that is cold-swaged onto the bar end(s).3.1.4.1 DiscussionThe coupling sleeve assembly is at-tached to the deformed reinforcing bar by cold-swaging thetubular sleeve portion to the bar with multiple crimps from ahydraulic swaging tool and die, up to the face of the pre-threaded section. Thi
23、s coupling sleeve is pre-threaded withexternal threads, which match threads internal to the head(s).The head is screwed onto the mating threads on the couplingsleeve. The threads may be parallel or tapered.3.1.5 ferrous-filler coupling sleeve headed bar, nsteelreinforcing bar that has the head(s) at
24、tached by means of acoupling sleeve mechanically attached to the bar via aninterlock of ferrous-filler material and the bar deformations.3.1.5.1 DiscussionThe ferrous-filler material is cast intothe coupling sleeve. A variation includes a separate internallythreaded nut secured to the threaded bar e
25、nd or attached viawelding a plate to the end of a prepared coupling sleeve.3.1.6 forged headed bar, nsteel reinforcing bar that has thehead(s) integrally forged.3.1.7 head, nround, elliptical, or rectangular shape used toanchor a steel reinforcing bar in concrete.3.1.8 net bearing area, ngross cross
26、-sectional area of thehead minus the nominal cross-sectional area of the deformedreinforcing bar.3.1.9 threaded headed bar, nsteel reinforcing bar that hasthe head(s) attached using tapered or straight threads internal tothe head or by a separate internally threaded nut securing thehead to the threa
27、ded bar end.3.1.10 welded headed bar, nsteel reinforcing bar that hasthe head(s) welded.4. Ordering Information4.1 Orders for headed steel bars for concrete reinforcementunder this specification shall contain following information:4.1.1 Quantity;4.1.2 Type of product: welded, forged, cold-swaged, co
28、ld-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 thickness, diameter orheight and width of the head;4.1.7 Number of heads per bar length;4
29、.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 additionalrequirements, including, but not limited to, the following:4.2.1 Packaging (15.1, 15.2);4.2.2 Bend testing of welded headed bars in sizes No. 11,14, and 18 36, 43, an
30、d 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 Reinforcing BarsFor welded headed bars, the rein-forcing bars shall conform to Specification A706/A7
31、06M. Forforged non-welded headed bars, the reinforcing bars shallconform to Specification A615/A615M or A706/A706M,asspecified by the purchaser.5.2 Heads:5.2.1 The head material shall be selected by the manufac-turer.5.3 The head dimensions shall be provided by the purchaserin the order. Head dimens
32、ions shall define the head geometryincluding thickness, diameter, or height and width of the head(Fig. 1). Alternate head dimensions supplied by the manufac-turer shall be permitted if agreed to in advance by thepurchaser. The manufacturer shall furnish documentation to thepurchaser, in the form of
33、calculations or test reports, or both,that confirms the suitability of alternate head dimensions forthe intended application.NOTE 2Alternate head dimensions resulting in a net bearing area lessthan four times the nominal cross-sectional area of the deformed reinforc-ing bar are not suitable for use
34、in construction projects governed by certainconsensus building codes and design standards (see 5.4 and Note 3).5.4 When specified by the purchaser in the purchase orderor contract as a class HA headed bar, head dimensions shallmeet the requirements of Annex A1.NOTE 3Some methods of attachment, as de
35、fined in Section 3 of thisspecification, do not meet the requirements on obstructions as prescribedA970/A970M 162in Annex A1. The requirements for head dimensions, limitations toreinforcing bar deformation interruptions and the size of obstructionallowances provided in Annex A1 are mandated by certa
36、in consensusbuilding codes and design standards, for example, “Building CodeRequirements for Structural Concrete (ACI 318).“ Heads with obstruc-tions that do not conform to Annex A1 may not be permitted for use bycertain building codes and design standards, such as ACI 318.5.5 WeldingA welding proce
37、dure conforming toAWS D1.4 D1.4M shall be used for all required productionwelding of the head to the bar, except for friction welding thatshall conform to AWS C6.1 in conjunction with the manufac-turers QA/QC procedures.5.6 ForgingFor integrally forged headed bars, the headsshall be produced by defo
38、rming the bar ends in a hot-forgingprocess.5.7 Threading:5.7.1 Threads on bars shall be either tapered or straight. Thehead shall either thread onto the bar directly, or it shall be heldon the bar end by a nut and counternut. Thread specificationsand standards shall be selected by the manufacturer.5
39、.7.2 The out-of-roundness in the as-rolled reinforcing barshall be evaluated so that the manufacturers minimum threaddimensions are maintained.5.7.3 It shall be permissible to hot- or cold-roll, or machinecut, threads into the surface of the bar and heads at the optionof the manufacturer.6. Mechanic
40、al Test and Performance Requirements6.1 Headed bars shall be subjected to mechanical tests toverify production method and product quality prior to manu-facture. Mechanical testing also shall be performed at intervalsduring production of the assembly.6.2 Tensile Tests:6.2.1 Tensile testing of the hea
41、ded bar assembly shall beperformed in accordance with the requirements described inTest Methods and Definitions A370. The failure mode shall bereported as partial or total fracture of the bar, the head, or thehead-to-bar connection.6.2.2 Specimen PreparationTensile test specimens shallbe the full cr
42、oss-section of the bar with a head attached to oneend of the reinforcing bar. The minimum length of the testspecimen shall be the greater of 10 in. 250 mm or ten timesthe nominal diameter of the bar. The test specimen shall beplaced in the testing machine with the head supported toprevent movement a
43、nd bending of the head. Provisions shall bemade for clearance between the support and any weld orforming material on the reinforcing bar-to-head connection.The opposite bar end of the bar, without a head attached, shallbe gripped by the testing machine and loaded to failure.6.3 Tensile Requirements:
44、6.3.1 Tensile PropertiesThe tensile properties of the testspecimen shall conform to one of the following classes:6.3.1.1 Class ADevelop the minimum specified tensilestrength of the reinforcing bar.6.3.1.2 Class BDevelop the minimum specified tensilestrength and the minimum specified elongation of th
45、e reinforc-ing bar.NOTE 4Reference the requirements of Specifications A615/A615Mand A706/A706M for minimum reinforcing bar tensile properties. ClassAhas been introduced for applications that require the development of theminimum tensile strength of the reinforcing bar. The Class B criteriarequires t
46、he head and the head-to-bar connection to meet or exceed theminimum specified tensile strength and the minimum specified elongationrequirements of the reinforcing bar. In the previous criteria, the failure ofthe head or the head-to-bar connection within the attachment region wascause for rejection.6
47、.4 Bend Test Requirements:6.4.1 Only welded headed bars in sizes No. 3 to 10 10 to32 shall be subject to bend testing. Bend testing of weldedheaded bars in sizes No. 11, 14, and 18 36, 43, and 57 shallbe subject to agreement between the purchaser and manufac-turer.NOTE 5Serious safety issues may be
48、involved in performing bendtests on welded headed bars in sizes No. 11, 14, and 18 36, 43, and 57.Thus, 6.4 requires such bend testing to be subject to agreement betweenthe purchaser and manufacturer.6.4.2 ProcedureThe test specimen shall be bent around amandrel of suitable diameter to an angle of a
49、t least 90 with noobserved partial or total fracture of the head, the bar, or thehead-to-bar connection.6.4.3 Bend Test MandrelThe mandrel shall be placed so asto directly bend the welded region. The required mandrelFIG. 1 Headed Reinforcing BarA970/A970M 163dimensions for bend testing are prescribed in Table 1. Thecenterline of the bend test mandrel shall be placed at theintersection of the reinforcing bar and the weld, as shown inFig. 2.6.4.4 Specimen PreparationBend test specimens shall bethe full cross-section of the bar with a
