1、Designation: A416/A416M 15Standard Specification forLow-Relaxation, Seven-Wire Steel Strand for PrestressedConcrete1This standard is issued under the fixed designation A416/A416M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the
2、 year 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.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 This specification cov
3、ers two grades of low-relaxation,seven-wire steel strand for use in prestressed concrete con-struction. Grade 250 1725 and Grade 270 1860 haveminimum tensile strengths of 250 ksi 1725 MPa and 270 ksi1860 MPa, respectively, based on the nominal area of thestrand.1.2 A supplementary requirement (S1) i
4、s provided for usewhere bond strength testing of 0.600-in. 15.24-mm diameterGrade 270 1860 strand for applications in prestressed groundanchors is required by the purchaser. The supplementaryrequirement applies only when specified in the purchase order.1.3 The text of this specification contains not
5、es or footnotes,or both, that provide explanatory material. Such notes andfootnotes do not contain any mandatory information.1.4 This specification is applicable for orders in eitherinch-pound units (as Specification A416) or in SI units (asSpecification A416M).1.5 The values stated in either inch-p
6、ound 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 independently of the other. Combining valuesfrom the two systems may result in non-co
7、nformance with thespecification.2. Referenced Documents2.1 ASTM Standards:2A981/A981M Test Method for Evaluating Bond Strength for0.600-in. 15.24-mm Diameter Steel Prestressing Strand,Grade 270 1860, Uncoated, Used in Prestressed GroundAnchorsA1061/A1061M Test Methods for Testing Multi-Wire SteelStr
8、and2.2 U.S. Military Standard:3MIL-STD-129 Marking for Shipment and Storage2.3 U.S. Federal Standard:3Fed. Std. No. 123 Marking for Shipments (Civil Agencies)3. Terminology3.1 Definition of Term Specific to This Specification:=3.1.1 strand, na group of wires having a center wireenclosed tightly by s
9、ix helically placed outer wires withuniform pitch of not less than 12 and not more than 16 timesthe nominal diameter of the strand.3.1.1.1 DiscussionThe direction of lay may be eitherright- or left-hand; however, strands of different lays should notbe spliced together.4. Ordering Information4.1 It s
10、hall be the responsibility of the purchaser to specifyall requirements that are necessary for material ordered underthis specification. Such requirements to be considered include,but are not limited to, the following:4.1.1 Quantity (feet metres),4.1.2 Nominal diameter of strand,4.1.3 Grade of strand
11、,4.1.4 Specially dimensioned strand (7.4), if desired,4.1.5 Weldless, if desired (8.1),4.1.6 Outside inspection, if required (11.1),4.1.7 Load-elongation curve, if desired (13.2),4.1.8 Packaging (14.1),4.1.9 Supplementary Requirement S1, if desired, and4.1.10 ASTM designation A416 A416M and year of
12、issue.5. Materials and Manufacture5.1 Base MetalThe base metal shall be carbon steel ofsuch quality that when drawn to wire, fabricated into strand,1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of Subc
13、ommitteeA01.05 on Steel Reinforcement.Current edition approved May 1, 2015. Published June 2015. Originallyapproved in 1957. Last previous edition approved in 2012 as A416/A416M 12a.DOI: 10.1520/A0416_A0416M-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Cust
14、omer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/dodssp.daps.dla.
15、mil.*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 States1and then thermally treated, shall have the properties andcharacteristics prescribed in this specification.5.2 WireThe
16、 wire from which the strand is to be fabricatedshall be round and have a dry-drawn finish.NOTE 1This product is a composite of seven wires and is producedonly to meet the prescribed mechanical properties. The chemical compo-sition of all wires or any individual wire is not pertinent to this applicat
17、ion,and heat identity is not necessarily maintained. It is possible that wirefrom more than one heat may be used in the manufacture of a reel orreelless pack. Traceability is based on identity of reels or reelless packs asmaintained and reported by the manufacturer.5.3 TreatmentAfter stranding, stra
18、nd shall be subjected toa continuous thermal-mechanical treatment to produce theprescribed mechanical properties. Temper colors which resultfrom the thermal-mechanical treatment are considered normalfor the finished appearance of this strand.6. Mechanical Property Requirements6.1 Tests for mechanica
19、l properties shall be conducted inaccordance with Test Methods A1061/A1061M.6.2 Breaking StrengthThe breaking strength of the fin-ished strand shall conform to the requirements prescribed inTable 1.6.3 Yield StrengthYield strength in pounds kN shall bemeasured at 1 % extension under load. The minimu
20、m yieldstrength shall be 90 % of the breaking strength listed in Table1. Initial loads for the test and minimum yield strengths arelisted in Table 2.6.3.1 The extension under load shall be measured by anextensometer calibrated with the smallest division not largerthan 0.0001 in./in. 0.0001 mm/mm of
21、gage length.6.4 ElongationThe total elongation under load shall notbe less than 3.5 % using a gage length of not less than 24 in.600 mm. It shall be permissible to determine the totalelongation value by adding, to the 1.0 % yield extension, thepercent extension or movement between the jaws gripping
22、thestrand after yield determination. The percent is calculated onthe new base length of jaw-to-jaw distance.6.5 Relaxation PropertiesStrand shall have relaxationlosses of not more than 2.5 % when initially loaded to 70 % ofspecified minimum breaking strength or not more than 3.5 %when loaded to 80 %
23、 of specified minimum breaking strengthof the strand after 1000 hours of testing.6.5.1 If required, relaxation evidence shall be provided fromthe manufacturers records of tests on similarly dimensionedstrand of the same grade.7. Dimensions and Permissible Variations7.1 The size of the finished stran
24、d shall be expressed as thenominal diameter of the strand in inches millimetres.7.2 The diameter of the center wire of any strand shall belarger than the diameter of any outer wire in accordance withTable 3.7.3 Permissible Variations in Diameter:7.3.1 All Grade 250 1725 strand shall conform to a siz
25、etolerance of 60.016 in. 60.40 mm from the nominal diam-eter measured across the crowns of the wires.7.3.2 All Grade 270 1860 strand shall conform to a sizetolerance of +0.026, 0.006 in. +0.65, 0.15 mm from thenominal diameter measured across the crowns of the wires.7.3.3 Variation in cross-sectiona
26、l area and in unit stressresulting therefrom shall not be cause for rejection providedTABLE 1 Breaking Strength RequirementsNominal Diameterof Strand, in. mmMinimum BreakingStrength ofStrand, lbf kNSteel Area ofStrand, in.2mm2Weight Mass ofStrand lb/1000 ftkg/1000 mGrade 250 17250.250 6.4 9 000 40.0
27、 0.036 23 122 1820.313 7.9 14 500 64.5 0.058 37 197 2940.375 9.5 20 000 89.0 0.080 52 272 4050.438 11.1 27 000 120 0.108 69.7 367 5480.500 12.7 36 000 160 0.144 92.9 490 7300.600 15.2 54 000 240 0.216 139 737 1090Grade 270 18600.375 9.53 23 000 102 0.085 55 290 4300.438 11.1 31 000 138 0.115 74.2 39
28、0 5800.500 12.7 41 300 184 0.153 98.7 520 7800.520 13.2 45 000 200 0.167 108 570 8400.563 14.3 51 700 230 0.192 124 650 9700.600 15.2 58 600 261 0.217 140 740 11000.620 15.7 62 800 279 0.231 150 780 12000.700 17.8 79 400 353 0.294 190 1000 1500TABLE 2 Yield Strength RequirementsNominal Diameter ofSt
29、rand in. mmInitial Load, lbf kNMinimum Load at 1 %Extension, lbf kNGrade 250 17250.250 6.4 900 4.0 8 100 36.00.313 7.9 1 450 6.5 13 050 58.10.375 9.5 2 000 8.9 18 000 80.10.438 11.1 2 700 12.0 24 300 108.10.500 12.7 3 600 16.0 32 400 144.10.600 15.2 5 400 24.0 48 600 216.2Grade 270 18600.375 9.53 2
30、300 10.2 20 700 92.10.438 11.1 3 100 13.8 27 900 124.10.500 12.7 4 130 18.4 37 170 165.30.520 13.2 4 500 20.0 40 500 180.10.563 14.3 5 170 23.0 46 530 207.00.600 15.2 5 860 26.1 52 740 234.60.620 15.7 6 280 27.9 56 520 251.40.700 17.8 7 940 35.3 71 500 318.0TABLE 3 Diameter Relation Between Center a
31、nd Outer WiresNominal Diameter of Strand, in.mmMinimum Difference Between CenterWire Diameter and Diameter of AnyOuter Wire, in. mmGrade 250 17250.250 6.4 0.001 0.0250.313 7.9 0.0015 0.0380.375 9.5 0.002 0.0510.438 11.1 0.0025 0.0640.500 12.7 0.003 0.0760.600 15.2 0.004 0.102Grade 270 18600.375 9.53
32、 0.002 0.0510.438 11.1 0.0025 0.0640.500 12.7 0.003 0.0760.520 13.2 0.003 0.0760.563 14.3 0.0035 0.0890.600 15.2 0.004 0.1020.620 15.7 0.004 0.1020.700 17.8 0.0045 0.114A416/A416M 152that the diameter differences of the individual wires and thediameters of the strand are within the tolerances specif
33、ied.7.4 It shall be permitted to furnish specially dimensionedstrands with nominal diameters up to 0.750 in. 19 mm. Thebreaking strength shall be defined, and the yield strength, asdefined in 6.3, shall not be less than 90 % of the specifiedminimum breaking strength.All other requirements shall appl
34、y.8. Workmanship, Finish, and Appearance8.1 Joints:8.1.1 There shall be no strand joints or strand splices in anylength of the finished strand unless specifically permitted bythe purchaser.8.1.2 During the process of manufacture of individual wiresfor stranding, welding shall be permitted only prior
35、 to or at thesize of the last thermal treatment, for example, patenting orcontrolled cooling. There shall be no welds in the wire after ithas been drawn through the first die in the wire drawing exceptas provided in 8.1.3.8.1.3 During fabrication of the strand, butt-welded joints arepermitted in the
36、 individual wires, provided there shall not bemore than one such joint in any 150-ft 45-m section of thefinished strand.8.1.4 When specifically ordered as “Weldless,” a productfree of welds shall be furnished. When “Weldless” is specified,the strand is produced as one continuous length with no welds
37、as allowed by 8.1.3.8.2 The finished strand shall be uniform in diameter andshall be free of imperfections.8.3 When the strand is cut without seizings, the wire shallnot fly out of position. If any wire flies out of position and canbe replaced by hand, the strand shall be considered satisfactory.8.4
38、 The strand shall not be oiled or greased. Slight rusting,provided it is not sufficient to cause pits visible to a person withnormal or corrected vision, shall not be cause for rejection.NOTE 2Guidance for evaluating the degree of rusting on prestressedconcrete strand is presented in Sason.49. Sampl
39、ing9.1 Test specimens cut from either end of the reel or reellesspack are permitted.Any specimen found to contain a wire jointshall be discarded and a new specimen obtained.10. Number of Tests10.1 One test specimen shall be taken from each 30-ton27-tonne production lot of finished strand, and tested
40、 forbreaking strength, yield strength, and elongation.11. Inspection11.1 If outside inspection is required, the manufacturer shallafford the inspector representing the purchaser reasonableaccess to the facilities, which concern the manufacture of thematerial ordered, to satisfy the inspector that th
41、e material isbeing furnished in accordance with this specification. All testsand inspections shall be made at the place of manufacture priorto shipment, unless otherwise agreed upon at the time ofpurchase, and shall be so conducted as not to interfereunnecessarily with the manufacturers operations.1
42、2. Rejection12.1 Failure of any test specimen to comply with therequirements of the specification shall constitute grounds forrejection of the production lot represented by the specimen.12.2 The production lot shall be resubmitted for inspectionby testing a specimen from each reel or reelless pack a
43、ndsorting out non-conforming material.12.3 If there is a reasonable doubt in the initial testing as tothe ability of the strand to meet any requirement of thisspecification, two additional tests shall be made on specimensof strand from the same reel or reelless pack, and if failureoccurs in either o
44、f these tests, the strand shall be rejected.13. Certification13.1 If outside inspection is not required, a manufacturerscertification that the material has been tested in accordancewith and meets the requirements of this specification shall bethe basis of acceptance of the material. The certificatio
45、n shallinclude the specification number, year of issue, and revisionletter, if any.13.2 When requested in the purchase order or contract, themanufacturer shall furnish a representative load-elongationcurve for each size and grade of strand shipped.13.3 When the modulus of elasticity of a seven-wire
46、strandis provided, the cross-sectional area used to calculate thatmodulus also shall be provided. The area provided in thecertification shall be the area used to calculate the modulus ofelasticity.13.4 A material test report, certificate of inspection, orsimilar document printed from or used in elec
47、tronic form froman electronic data interchange (EDI) transmission shall beregarded as having the same validity as a counterpart printed inthe certifiers facility. The content of the EDI transmitteddocument shall meet the requirements of the invoked ASTMstandard(s) and conform to any existing EDI agr
48、eement be-tween the purchaser and the manufacturer. Notwithstanding theabsence of a signature, the organization submitting the EDItransmission is responsible for the content of the report.NOTE 3The industry definition as invoked here is: EDI is thecomputer-to-computer exchange of business information in a standardformat such as ANSI ASC X12.14. Packaging and Package Marking14.1 The strand shall be furnished on reels or in reellesspacks having a minimum core diameter of 24 in. 610 mm,unless otherwise specified by the purchaser. The leng
