1、Designation: A416/A416M 12 A416/A416M 12aStandard Specification forSteel Strand, Uncoated Seven-Wire 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 revi
2、sion, 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 Department of Defense.1. Scope*1.1 This specification
3、 covers two types and two grades of seven-wire, uncoated steel strand for use prestressed concreteconstruction. The two types of strand are low-relaxation and stress-relieved (normal-relaxation). Low-relaxation strand is to beregarded as the standard type. Stress-relieved (normal-relaxation) strand
4、will not be furnished unless specifically ordered. Grade250 1725 and Grade 270 1860 have minimum tensile strengths of 250 ksi 1725 MPa and 270 ksi 1860 MPa, respectively,based on the nominal area of the strand.1.2 A supplementary requirement (S1) is provided for use where bond strength testing of 0.
5、600-in. 15.24-mm diameter Grade270 1860 strand for applications in prestressed ground anchors is required by the purchaser. The supplementary requirementapplies only when specified in the purchase order.1.3 This specification is applicable for orders in either inch-pound units (as Specification A416
6、A416) or in SI units (asspecificationSpecification A416MA416M).).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
7、system shall be usedindependently of the other. Combining values from the two systems may result in non-conformance with the specification.2. Referenced Documents2.1 ASTM Standards:2A981/A981M Test Method for Evaluating Bond Strength for 0.600-in. 15.24-mm Diameter Steel Prestressing Strand, Grade27
8、0 1860, Uncoated, Used in Prestressed Ground AnchorsA1061/A1061M Test Methods for Testing Multi-Wire Steel Strand2.2 U.S. Military Standards: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 Definitions o
9、f Terms Specific to This Standard:3.1.1 strand, na group of wires having a center wire enclosed tightly by six helically placed outer wires with uniform pitchof not less than 12 and not more than 16 times the nominal diameter of the strand.3.1.1.1 DiscussionThe direction of lay may be either right-
10、or left-hand, however, strands of different lays should not be spliced together.1 This specification is under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee A01.05on Steel Reinforcement.Current edition approved Apr
11、il 1, 2012Sept. 1, 2012. Published May 2012October 2012. Originally approved in 1957. Last previous edition approved in 20102012 asA416 10.A416/A416M 12. DOI: 10.1520/A0416_A0416M-12.10.1520/A0416_A0416M-12A.2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Custo
12、mer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/dodssp.daps.dl
13、a.mil.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 accurately, ASTM recommends that users consult pri
14、or 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 Drive, PO Box C700, West Conshohocken, PA 194
15、28-2959. United States14. Ordering Information4.1 It shall be the responsibility of the purchaser to specify all requirements that are necessary for material ordered under thisspecification. Such requirements to be considered include, but are not limited to, the following:4.1.1 Quantity (feet metres
16、),4.1.2 Nominal diameter of strand,4.1.3 Grade of strand,4.1.4 Type of strand,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
17、and year of issue.5. Materials and Manufacture5.1 Base MetalThe base metal shall be carbon steel of such quality that when drawn to wire, fabricated into strand, and thenthermally treated, shall have the properties and characteristics prescribed in this specification.5.2 WireThe wire from which the
18、strand is to be fabricated shall be round and have a dry-drawn finish.NOTE 1This product is a composite of seven wires and is produced only to meet the prescribed mechanical properties. The chemical compositionof all wires or any individual wire is not pertinent to this application, and heat identit
19、y is not necessarily maintained. It is possible that wire from morethan one heat may be used in the manufacture of a reel or reelless pack. Traceability is based on identity of reels or reelless packs as maintained andreported by the manufacturer.5.3 TreatmentAfter stranding, low-relaxation strand s
20、hall be subjected to a continuous thermal-mechanical treatment toproduce the prescribed mechanical properties. For stress-relieved (normal-relaxation) strand, only thermal treatment is necessary.Temper colors which result from the stress-relieving operation are considered normal for the finished app
21、earance of this strand.6. Mechanical Property Requirements6.1 Tests for mechanical properties shall be conducted in accordance with Test Methods A1061/A1061M.6.2 Breaking StrengthThe breaking strength of the finished strand shall conform to the requirements prescribed in Table 1.TABLE 1 Breaking Str
22、ength RequirementsNominal Diameter ofStrand, in. mmMinimum BreakingStrength of Strand, lbf kNSteel Area of Strand, in.2mm2Weight Mass of Strandlb/1000 ft kg/1000 mGrade 250 17250.250 6.4 9 000 40.0 0.036 23.2 122 1820.250 6.4 9 000 40.0 0.036 23 122 1820.313 7.9 14 500 64.5 0.058 37.4 197 2940.313 7
23、.9 14 500 64.5 0.058 37 197 2940.375 9.5 20 000 89.0 0.080 51.6 272 4050.375 9.5 20 000 89.0 0.080 52 272 4050.438 11.1 27 000 120.1 0.108 69.7 367 5480.438 11.1 27 000 120 0.108 69.7 367 5480.500 12.7 36 000 160.1 0.144 92.9 490 7300.500 12.7 36 000 160 0.144 92.9 490 7300.600 15.2 54 000 240.2 0.2
24、16 139.4 737 10940.600 15.2 54 000 240 0.216 139 737 1090Grade 270 18600.375 9.53 23 000 102.3 0.085 54.8 290 4320.375 9.53 23 000 102 0.085 55 290 4300.438 11.11 31 000 137.9 0.115 74.2 390 5820.438 11.1 31 000 138 0.115 74.2 390 5800.500 12.70 41 300 183.7 0.153 98.7 520 7750.500 12.7 41 300 184 0
25、.153 98.7 520 7800.520 13.20 45 000 200.2 0.167 107.7 568 8440.520 13.2 45 000 200 0.167 108 570 8400.563 14.29 51 700 230.0 0.192 123.9 651 9700.563 14.3 51 700 230 0.192 124 650 9700.600 15.24 58 600 260.7 0.217 140.0 740 11020.600 15.2 58 600 261 0.217 140 740 11000.620 15.75 62 370 277.4 0.231 1
26、49.2 778 11730.620 15.7 62 800 279 0.231 150 780 12000.700 17.78 79 400 353.2 0.294 189.7 1000 14870.700 17.8 79 400 353 0.294 190 1000 1500A416/A416M 12a26.3 Yield StrengthYield strength in pounds kN shall be measured at 1 % extension under load. The minimum yield strengthshall be 90 % for low-rela
27、xation strand and 85 % for stress-relieved (normal-relaxation) strand of the breaking strength listed inTable 1. Initial loads for the test and minimum yield strengths are listed in Table 2.6.3.1 The extension under load shall be measured by an extensometer calibrated with the smallest division not
28、larger than0.0001 in./in. 0.0001 mm/mm of gage length.6.4 ElongationThe total elongation under load shall not be less than 3.5 % using a gage length of not less than 24 in. 600mm. It shall be permissible to determine the total elongation value by adding, to the 1.0 % yield extension, the percent ext
29、ensionor movement between the jaws gripping the strand after yield determination. The percent is calculated on the new base length ofjaw-to-jaw distance.6.5 Relaxation PropertiesLow-relaxation strand shall have relaxation losses of not more than 2.5 % when initially loaded to70 % of specified minimu
30、m 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 from the manufacturers records of tests on similarly dimensioned strandof the same grade.7. Dimensio
31、ns and Permissible Variations7.1 The size of the finished strand shall be expressed as the nominal diameter of the strand in inches millimetres.7.2 The diameter of the center wire of any strand shall be larger than the diameter of any outer wire in accordance with Table3.7.3 Permissible Variations i
32、n Diameter:7.3.1 All Grade 250 1725 strand shall conform to a size tolerance of 60.016 in. 60.40 mm from the nominal diametermeasured across the crowns of the wires.7.3.2 All Grade 270 1860 strand shall conform to a size tolerance of +0.026, 0.006 in. +0.65, 0.15 mm from the nominaldiameter measured
33、 across the crowns of the wire.7.3.3 Variation in cross-sectional area and in unit stress resulting therefrom shall not be cause for rejection provided that thediameter differences of the individual wires and the diameters of the strand are within the tolerances specified.7.4 It shall be permitted t
34、o furnish, under this specification, specially dimensioned low-relaxation and stress-relieved(normal-relaxation) strands with nominal diameters up to 0.750 in. 19 mm. The breaking strength shall be defined, and the yieldstrength, as defined in 6.3, shall not be less than 90 % and 85 % of the specifi
35、ed minimum breaking strength for low-relaxationand stress-relieved (normal-relaxation) strands, respectively. All other requirements shall apply.8. Workmanship, Finish, and Appearance8.1 Joints:TABLE 2 Yield Strength RequirementsNominal Diameterof Strandin. mmInitial Load,lbf kNMinimum Load at 1 % E
36、xtension,lbf kNLow-Relaxation Normal-RelaxationGrade 250 17250.250 6.4 900 4.0 8 100 36.0 7 650 34.00.313 7.9 1 450 6.5 13 050 58.1 12 300 54.70.375 9.5 2 000 8.9 18 000 80.1 17 000 75.60.438 11.1 2 700 12.0 24 300 108.1 23 000 102.30.500 12.7 3 600 16.0 32 400 144.1 30 600 136.20.600 15.2 5 400 24.
37、0 48 600 216.2 45 900 204.2Grade 270 18600.375 9.53 2 300 10.2 20 700 92.1 19 550 87.00.438 11.11 3 100 13.8 27 900 124.1 26 350 117.20.438 11.1 3 100 13.8 27 900 124.1 26 350 117.20.500 12.70 4 130 18.4 37 170 165.3 35 100 156.10.500 12.7 4 130 18.4 37 170 165.3 35 100 156.10.520 13.20 4 500 20.0 4
38、0 500 180.1 38 250 170.10.520 13.2 4 500 20.0 40 500 180.1 38 250 170.10.563 14.29 5 170 23.0 46 530 207.0 43 950 195.50.563 14.3 5 170 23.0 46 530 207.0 43 950 195.50.600 15.24 5 860 26.1 52 740 234.6 49 800 221.50.600 15.2 5 860 26.1 52 740 234.6 49 800 221.50.620 15.75 6 240 27.7 56 130 249.7 53
39、020 235.90.620 15.7 6 280 27.9 56 520 251.4 53 380 237.40.700 17.78 7 940 35.3 71 500 318.0 67 500 300.20.700 17.8 7 940 35.3 71 500 318.0 67 500 300.2A416/A416M 12a38.1.1 There shall be no strand joints or strand splices in any length of the completed strand unless specifically permitted by thepurc
40、haser.8.1.2 During the process of manufacture of individual wires for stranding, welding shall be permitted only prior to or at the sizeof the last thermal treatment, for example, patenting or controlled cooling. There shall be no welds in the wire after it has beendrawn through the first die in the
41、 wire drawing except as provided in 8.1.3.8.1.3 During fabrication of the strand, butt-welded joints are permitted in the individual wires, provided there shall not be morethan one such joint in any 150-ft 45-m section of the completed strand.8.1.4 When specifically ordered as “Weldless,” a product
42、free of welds shall be furnished. When “Weldless” is specified, thestrand is produced as one continuous length with no welds as allowed by 8.1.3.8.2 The finished strand shall be uniform in diameter and shall be free of imperfections.8.3 When the strand is cut without seizings, the wire shall not fly
43、 out of position. If any wire flies out of position and can bereplaced 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
44、 for rejection.NOTE 2Guidance for evaluating the degree of rusting on prestressed concrete strand is presented in Sason.49. Sampling9.1 Test specimens cut from either end of the reel or reelless pack are permitted. Any specimen found to contain a wire jointshall be discarded and a new specimen obtai
45、ned.10. Number of Tests10.1 One test specimen for test shall be taken from each 20-ton 18-Mg production lot of finished strand, and tested forbreaking strength, yield strength, and elongation.11. Inspection11.1 If outside inspection is required, the manufacturer shall afford the inspector representi
46、ng the purchaser reasonable accessto the facilities, which concern the manufacture of the material ordered, to satisfy the inspector that the material is being furnishedin accordance with this specification. All tests and inspections shall be made at the place of manufacture prior to shipment, unles
47、sotherwise agreed upon at the time of purchase, and shall be so conducted as not to interfere unnecessarily with the manufacturersoperations.4 Sason, A.S., “Evaluation of Degree of Rusting on Prestressed Concrete Strand, PCI Journal, Precast/Prestressed Concrete Institute, Vol 37, No. 3, MayJune 199
48、2, pp.2530. Reprints of this paper are available from the Precast/Prestressed Concrete Institute, 200 West Adams St., Suite 2100, Chicago, IL 60606.TABLE 3 Diameter Relation Between Center and Outer WiresNominal Diameter of Strands,Strand,in. mmMinimum Difference BetweenCenter Wire Diameter and Diameterof Any Outer Wire, in. mmGrade 250 17250.250 6.4 0.001 0.0250.313 7.9 0.0015 0.0380.375
