ASTM A 416 A 416 M - 16

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ASTM A 416 A 416 M - 16
  Designation: A416/A416M − 16 Standard Specification for Low-Relaxation, Seven-Wire Steel Strand for PrestressedConcrete 1 This standard is issued under the fixed designation A416/A416M; the number immediately following the designation indicates the yearof srcinal adoption or, in the case of revision, the 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 covers 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 ksi[1860 MPa], respectively, based on the nominal area of thestrand.1.2 A supplementary requirement (S1) is 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 notes 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-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 independently of the other. Combining valuesfrom the two systems may result in non-conformance with thespecification. 2. Referenced Documents 2.1  ASTM Standards: 2 A981/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 SteelStrand2.2  U.S. Military Standard: 3 MIL-STD-129 Marking for Shipment and Storage2.3  U.S. Federal Standard: 3 Fed. Std. No. 123 Marking for Shipments (Civil Agencies) 3. Terminology 3.1  Definition of Term Specific to This Specification: 3.1.1  strand, n—  a group of wires having a center wireenclosed tightly by six helically placed outer wires withuniform pitch of not less than 12 and not more than 16 timesthe nominal diameter of the strand.  Discussion—  The direction of lay may be eitherright- or left-hand. 4. Ordering Information 4.1 It shall 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,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 issue. 5. Materials and Manufacture 5.1  Base Metal—  The base metal shall be carbon steel of such quality that when drawn to wire, fabricated into strand, 1 This 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 1957. Last previous edition approved in 2015 as A416/A416M – 15.DOI: 10.1520/A0416_A0416M-16. 2 For referenced ASTM standards, visit the ASTM website,, orcontact ASTM Customer Service at For  Annual Book of ASTM Standards  volume information, refer to the standard’s Document Summary page onthe ASTM website. 3 Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:// *A Summary of Changes section appears at the end of this standard Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States     -    -        `  ,  ,        `  ,  ,        `        `        `  ,        `        `        `  ,  ,  ,  ,        `  ,        `        `        `        `  ,  ,        `  ,  ,        `    -        `    -        `  ,  ,        `  ,  ,        `  ,        `  ,  ,        `    -    -    -  and then thermally treated, shall have the properties andcharacteristics prescribed in this specification.5.2  Wire—  The wire from which the strand is to be fabricatedshall be round and have a dry-drawn finish. N OTE  1—This 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 application,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  Treatment—  After stranding, strand 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 Requirements 6.1 Tests for mechanical properties shall be conducted inaccordance with Test Methods A1061/A1061M.6.2  Breaking Strength—  The breaking strength of the fin-ished strand shall conform to the requirements prescribed inTable 1.6.3  Yield Strength—  Yield strength in pounds [kN] shall bemeasured at 1.0 % extension under load. The minimum yieldstrength shall be 90 % of the breaking strength listed in Table1. Initial loads for the test and minimum yield strengths arelisted in Table 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 gage length.6.4  Elongation—  The 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 thestrand after yield determination. The percent is calculated onthe new base length of jaw-to-jaw distance.6.5  Relaxation Properties—  Strand shall have relaxationlosses of not more than 2.5 % when initially loaded to 70 % of specified minimum breaking strength or not more than 3.5 %when loaded to 80 % of specified minimum breaking strengthof the strand after 1000 hours of testing.6.5.1 If required, relaxation evidence shall be provided fromthe manufacturer’s records of tests on similarly dimensionedstrand of the same grade. 7. Dimensions and Permissible Variations 7.1 The size of the finished strand 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 sizetolerance of   6 0.016 in. [ 6 0.40 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-sectional area and in unit stressresulting therefrom shall not be cause for rejection provided TABLE 1 Breaking Strength Requirements Nominal Diameterof Strand, in. [mm]Minimum BreakingStrength ofStrand, lbf [kN]Steel Area ofStrand, in. 2 [mm 2 ]Weight [Mass] ofStrand lb/1000 ft[kg/1000 m]Grade 250 [1725]0.250 [6.4] 9 000 [40.0] 0.036 [23] 122 [182]0.313 [7.9] 14 500 [64.5] 0.058 [37] 197 [294]0.375 [9.5] 20 000 [89.0] 0.080 [52] 272 [405]0.438 [11.1] 27 000 [120] 0.108 [69.7] 367 [548]0.500 [12.7] 36 000 [160] 0.144 [92.9] 490 [730]0.600 [15.2] 54 000 [240] 0.216 [139] 737 [1090]Grade 270 [1860]0.375 [9.53] 23 000 [102] 0.085 [55] 290 [430]0.438 [11.1] 31 000 [138] 0.115 [74.2] 390 [580]0.500 [12.7] 41 300 [184] 0.153 [98.7] 520 [780]0.520 [13.2] 45 000 [200] 0.167 [108] 570 [840]0.563 [14.3] 51 700 [230] 0.192 [124] 650 [970]0.600 [15.2] 58 600 [261] 0.217 [140] 740 [1100]0.620 [15.7] 62 800 [279] 0.231 [150] 780 [1200]0.700 [17.8] 79 400 [353] 0.294 [190] 1000 [1500] TABLE 2 Yield Strength Requirements Nominal Diameter ofStrand in. [mm] Initial Load, lbf [kN] Minimum Load at 1.0 %Extension, lbf [kN]Grade 250 [1725]0.250 [6.4] 900 [4.0] 8 100 [36.0]0.313 [7.9] 1 450 [6.5] 13 050 [58.1]0.375 [9.5] 2 000 [8.9] 18 000 [80.1]0.438 [11.1] 2 700 [12.0] 24 300 [108.1]0.500 [12.7] 3 600 [16.0] 32 400 [144.1]0.600 [15.2] 5 400 [24.0] 48 600 [216.2]Grade 270 [1860]0.375 [9.53] 2 300 [10.2] 20 700 [92.1]0.438 [11.1] 3 100 [13.8] 27 900 [124.1]0.500 [12.7] 4 130 [18.4] 37 170 [165.3]0.520 [13.2] 4 500 [20.0] 40 500 [180.1]0.563 [14.3] 5 170 [23.0] 46 530 [207.0]0.600 [15.2] 5 860 [26.1] 52 740 [234.6]0.620 [15.7] 6 280 [27.9] 56 520 [251.4]0.700 [17.8] 7 940 [35.3] 71 500 [318.0] TABLE 3 Diameter Relation Between Center and Outer Wires Nominal Diameter of Strand, in.[mm]Minimum Difference Between CenterWire Diameter and Diameter of AnyOuter Wire, in. [mm]Grade 250 [1725]0.250 [6.4] 0.001 [0.025]0.313 [7.9] 0.0015 [0.038]0.375 [9.5] 0.002 [0.051]0.438 [11.1] 0.0025 [0.064]0.500 [12.7] 0.003 [0.076]0.600 [15.2] 0.004 [0.102]Grade 270 [1860]0.375 [9.53] 0.002 [0.051]0.438 [11.1] 0.0025 [0.064]0.500 [12.7] 0.003 [0.076]0.520 [13.2] 0.003 [0.076]0.563 [14.3] 0.0035 [0.089]0.600 [15.2] 0.004 [0.102]0.620 [15.7] 0.004 [0.102]0.700 [17.8] 0.0045 [0.114] A416/A416M − 16 --`,,`,,```,```,,,,`,````,,`,,`-`-`,,`,,`,`,,`---  that the diameter differences of the individual wires and thediameters of the strand are within the tolerances specified.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 specified minimum breaking strength.All other requirements shall apply. 8. Workmanship, Finish, and Appearance 8.1  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 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 During fabrication of the strand, butt-welded joints arepermitted in the 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 weldsas allowed by 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 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. N OTE  2—Guidance for evaluating the degree of rusting on prestressedconcrete strand is presented in Sason. 4 9. Sampling 9.1 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 Tests 10.1 One test specimen shall be taken from each 30-ton[27-tonne] production lot of finished strand, and tested forbreaking strength, yield strength, and elongation. 11. Inspection 11.1 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 the 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 of purchase, and shall be so conducted as not to interfereunnecessarily with the manufacturer’s operations. 12. Rejection 12.1 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 andsorting 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 of these tests, the strand shall be rejected. 13. Certification 13.1 If outside inspection is not required, a manufacturer’scertification that the material has been tested in accordancewith and meets the requirements of this specification shall bethe basis of acceptance of the material. The certification 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 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 of elasticity.13.4 A material test report, certificate of inspection, orsimilar document printed from or used in electronic form froman electronic data interchange (EDI) transmission shall beregarded as having the same validity as a counterpart printed inthe certifier’s facility. The content of the EDI transmitteddocument shall meet the requirements of the invoked ASTMstandard(s) and conform to any existing EDI agreement 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. N OTE  3—The 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 Marking 14.1 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 length of strand on reels or in reelless packs shall be as agreed upon atthe time of purchase. The strand shall be well protected against 4 Sason, A.S., “Evaluation of Degree of Rusting on Prestressed ConcreteStrand,’’  PCI Journal , Precast/Prestressed Concrete Institute, Vol 37, No. 3,May–June 1992, pp. 25–30. Reprints of this paper are available from thePrecast/Prestressed Concrete Institute, 200 WestAdams St., Suite 2100, Chicago, IL60606. A416/A416M − 16 --`,,`,,```,```,,,,`,````,,`,,`-`-`,,`,,`,`,,`---  mechanical injury in shipping as agreed upon at the time of purchase. Each reel or reelless pack shall have two durable tagssecurely fastened to it showing the length, size, grade, ASTMdesignation A416 [A416M], and the name of the manufacturer.One tag shall be positioned where it will not be inadvertentlylost during transit, such as inside the core of a reelless pack.The other tag shall be placed on the outside of a reelless pack for easy identification.14.2 When specified in the purchase order or contract, andfor direct procurement by or direct shipment to the U.S.Government, marking for shipment, in addition to require-ments specified in the purchase order or contract, shall be inaccordance with Fed. Std. No. 123 for civil agencies and MIL-STD-129 for military agencies. 15. Keywords 15.1 prestressed concrete; seven-wire strand (tendon); steelwire SUPPLEMENTARY REQUIREMENTS S1. Bond Strength of 0.600-in. [15.24-mm], Grade 270 [1860] Strand Used in Prestressed Ground Anchors The following supplementary requirement shall apply only when specified in the purchase order orcontract. S1.1 Bond Strength S1.1.1 These requirements are not applicable to strand usedin prestressed concrete applications.S1.1.2 The results of bond-strength tests performed inaccordance with Test Method A981/A981M shall be submittedto the purchaser. The strand specimens, on which tests wereperformed, shall be from different lots and shall be represen-tative for the strand ordered.S1.1.3 The average pull force from six pull tests, performedin accordance with Test Method A981/A981M, required to reach the 0.01-in. [0.25-mm] displacement described thereinshall be at least 8000 lbf [35.6 kN], with the individualminimum test value not less than 6800 lbf [30.2 kN]. For anyfuture retests, without changes in the manufacturing methodand materials used, three tests shall be considered as adequate.S1.1.4  Retests  —If the test specimens fail to satisfy S1.1.3,six additional tests shall be performed, and the results shallsatisfy the acceptance criteria. Strand that fails the retests shallnot be considered acceptable for use in prestressed groundanchors.S1.1.5  Annual Tests —The pull tests shall be performedannually as a minimum or repeated when, in the opinion of themanufacturer, a process change is made which is believedcould decrease the bond strength of the strand. SUMMARY OF CHANGES Committee A01 has identified the location of selected changes to this standard since the last issue(A416/A416M – 15) that may impact the use of this standard. (Approved March 1, 2016.) (1)  Revised A01 has identified the location of selected changes to this standard since the last issue(A416/A416M – 12a) that may impact the use of this standard. (Approved May 1, 2015.) (1)  Deleted “stress-relieved (normal-relaxation)” type of stand,revising the title, 1.1, 4.1.4, 5.3, 6.3, 7.4, 6.5, and Table 2. (2)  Revised 10.1 to update current production capabilities. A416/A416M − 16 --`   ,  ,`   ,  ,` ` `   ,` ` `   ,  ,  ,  ,`   ,` ` ` `   ,  ,`   ,  ,` -` -`   ,  ,`   ,  ,`   ,`   ,  ,` ---
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