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By Authority Of THE UNITED STATES OF AMERICA

Legally Binding Document

By the Authority Vested By Part 5 of the United States Code 552(a) andPart 1 of the Code of Regulations 51 the attached document has been dulyINCORPORATED BY REFERENCE and shall be considered legallybinding upon all citizens and residents of the United States of America.

HEED THIS NOTICE : Criminal penalties may apply for noncompliance.

Official Incorporator:T HE E XECUTIVE DIRECTOROFFICE OF THE FEDERAL REGISTER

WASHINGTON, D.C.

Document Name:

CFR Section(s):

Standards Body:

eASTM A416: Uncoated Seven-Wire Stress-RelievedStrand for Prestressed Concrete

24 CFR 200, Subpart S

American Society for Testing and Materials

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AMERICAN NATIONAL ANSI/ASTM A 416 74STANDARD

American Association StateHighway and Transportation Officials Standard

AASHTO No.: M 2 3

tandard pecification for

UNCOATED SEVEN WIRE STRESS RELIEVED

STRAND FOR PRESTRESSED CONCRETE

This Standard is issued under the fixed designation A 416; the number immediately rollowing the designation indicates the yearor original adoption or, in the case or revision, the year or last revision. A number in parentheses indicates the year or lastreapproval.This specification has been approved for use by agencies of the Department of Defense for listing in the DoD Index of

Specifications and Standards.

1. Scope

1.1 Th is specification covers two grades ofseven-wire, uncoated, stress-relieved steelstrand for use in pretensioned and post-tensioned prestressed concrete construction.Grade 250 and Grade 270 have minimumultimate strengths of strengths of 250 000 psi1725 MPa and 270 000 psi 1860 MPa , re

spectively, based on the nominal area of thestrand.

1.2 Supplement I describes low-relaxationstrand and relaxation testing for that product.Low relaxation strand shall not be furnishedunless ordered, or by arrangement betweenpurchaser and supplier.

NOTE I - T h e values stated in inch-pound unitsare to be regarded as the standard.

2. Applicable Documents

2 1 ASTM Standards:A 370, Methods and Definitions for Me

chanical Testing of Steel Products 2

E 380, Metric Practice 3

3. Description of Terms3 1 Strand All strand shall be of the seven

wire type having a center wire enclosed tightlyby six helically placed outer wires with auniform pitch of not less than 12 and not morethan 16 times the nominal diameter of thestrand.

4. Ordering Information4.1 Orders for seven-wire stress relieved

strand under this specification shall include thefollowing information:

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4.1.1 Quantity feet),4.1.2 Diameter of strand,4.1.3 Grade of strand,4.1.4 Packaging,4.1.5 ASTM designation and date of issue,

and4.1.6 Special requirements, if any.NOTE 2 A typical ordering description is as

follows: 84 000 ft,V

in., Grade 270 strand, in12 000 ft spool-less packs to ASTM A 416d a t e d .

5. Materials and Manufacture5 1 Base Metal The base metal shall be

carbon steel of such quality that when drawn tosuitable round wire sizes and fabricated intostrand sizes, and stress relieved after stranding,it shall have the properties and characteristicsprescribed in this specification.

5.2 Wire The wire from which the strand isto be fabricated shall have a common drydrawn finish.

5 3 Stress Relieving After stranding, allstrand shall be subjected to a stress-relievingcontinuous heat treatment to produce the prescribed mechanical properties. Temper colorswhich may result from the stress-relieving operation are considered normal for the finishedappearance of this strand.

I This specification is under the jurisdiction or ASTMCommittee A-Ion Steel, Stainless Steel and Related Alloys,and is the direct responsibility or Subcommittee AOl.05 onSteel Reinrorcement.

Current edition approved Sept. 27 1974. PublishedNovember 1974. Originally published as A 416 - 57 T.Last previous edition A 416 - 68.

2 Annual Book of ASTM Standards Parts I 2 3 4 5and ID.

a Annual Book o f ASTM Standards Part 41.

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,6.' h y ~ i c a lRequirements6 1 Breaking Strength The breaking

strength of the finished strand shall conform tothe requirements prescribed in Table I, andshall be determined as prescribed in Supplement VII of Methods and Definitions A 370.

6 2 Yield Strength The minimum yieldstrength, a s p r e s ~ r i b e din Table 2, as measuredby the I % extension under load method, shallnot be less than 85 % ,of the specified minimumbreaking strength.

6.2.1 The extension under-load shall be measured by an extensbmeter' calibrated with thesmallest division not larger than 0.000 I in./in.of gage length, .

6.2.2 The initial load indicated in Table 2shall be applied to the specimen", at .which timethe extensometer is attached 'ahd adjusted to areading of 0.00 I iri.)ii1.of gage length'. The loadshall then be increased uht}1 the extynsometerindicates an extension of I %. The load for thise ~ t e n s i o nshaH he r e d o r d ~ dand'shall ~ e e ttherequirements prescribed in Table 2.

6 3 Elongation > , , " ,6.3.1 t h e total elo'ngation, uhder Iqad, Mthe

s t r a r i d ~ h a l l ,be ~ o tI < ; s ~than}.S % and ~ l : J a l ( b emeasured in a gage length of not less than.24 in.ot 610 mm. The elongation shall be determinedby an extenso meier which is p1a:i::ed ii the test.speeirnen:after an initial load has, been applied., The; .initial .load .is cequivalent to l.0Wo. of therequired .minimum breaking strength as pre

,s,cribed in'Tab1'e 2, Eollowingan extension 0f1.0 %;' the. exH:nsometermay .,beFemoved andloading continued to ultimate failure. The elon'gation value is 'then determined by the movementbetween the jaw:s grippiilg the material onthe new base length of jaw-lo-jaw distanee,towhich wiUbe added the' VaHHi"of LO % determitiedby t h e e x t e n s 6 i r i e t ~ t .

, '6.3.2Specitnens that break outside of'theeXfensbnieter or in the j'awsaii'd yenneet theininimum specified Values, ate ,cbrtsidered as

'meeting the', elorigation requirements', of, thisspecification. ' , . 1 ' ; . '

6:3.3 If the minimum elongation requirement is met pt ibr lo initial tl}pture, it is notnecessary to dete,rrriiil(:, the' finalelongat,ionvalue. "

6.4' If M ~ y ,sampie :breaking ~ i t h i nthe gripsor the jaws of the testing machine results invahies belbW"thespecified limits fdr 'breaking

I I ; '

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strength, yield ~ i r e n g t h ,or e l o n g a t i ~ n ,theresults shall be considered invalid and retestingshall be required.

7. Dimensions and Permissible Variations

7.1 The size of the finished strand shall beexpressed as the n b m i ~ a ld i a ~ e t e rof the strandin fractions or decimal. fractions of an inch.

7.2 T h ~d i a ~ e t e rof the c e n t ~ rwire of anystrand must be larger than the diameter of anyouter wire in accordance with Table 3.

7 3 Permissible Variations in Diameter:7.3.1 All Grade 250 strand shall cohform to

a i ~ tolerance of O.O, 6in. (OAI mm) fromthe nominal diameter measured acro.ss the

crowns of the wires.7.3.2 All Grade 270 strand shall conform toa size tolerance of +0.026 in. -0.006 in;. (+0.66-0.15 inm fr m the n'omiiull diameter measured acrosS t ~ ecrowns o tile wire. "," 7.3.3 Variation in doss-sectional itrea alldinunit streSS resuitingtherefrdm shall nof be'cauie'fo t rejection provided the diameter differe t i c ~ sof the i n d i v i d U ~ i w i r e sarid the diameterso'f the t r ~ n d a i ewith'in the toletances specified.. '7.4 SpeciaJly dimensibned s t r e s s - r e H ~ v ~ C

strand with nominal diameters up to 0.75'0'ln.:(19.05 mm) may be employed, prov'iding thatthe breaking strength s defined; and the yieldstrength, as:deffned in 6.2; is not less than 8'5%Of; tlie' 'spedf iedtriir iimlim breaking" stre,liMh'.All other requirements shal l 'apply.

~ i t . .

8. Workmanship ;,} .d,,, ..

8 1 Joints: """;'" ,8.1.1 There shall be, no, strand joints or

stX lnq splices in any,iength of the com p etedstrand unless specifically permitted by the pur-chaser. . i .

8.1.2 During the process of manufacture ofthe individual wires for, stranding, welding isp e ~ r n i t t e dJnly p ' r i ~ r t qo r ~ } h esize ,qf the lastheat treatrnt:nt (patenting), " : :.

8:,\.3 D)Jrjng f a b r i ~ a t i o n ,of,the w a n 9 , . b l \ ~ t -. , w < ; : ~ d e O , j 9 i n t s , ' m a ybe madejl1 ,theinqividJJalwires, p r R v i q ~ d,ther,e i ~ npt mp\e than one, ~ 9 h

joint in any 150-ft (45-m) section of the ~ ~ r n -pleted strand.

NotE 3-When s p e c i f i d ~ l l y " ; 6 ' r d e r e da'S":"Welo.' 1 ~ ~ . s ~ 9 r a d e " "a, P . r o ~ u 9 tf r ~ . eo C . ' f : t I ~ s.$hall. be;fur'I'Hshed, When thIs 'grade IS speclfl,ed, no w ~ l d sorjointS 'ate;perniittedexcept air detailed in 8:1.2.'

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8.2 The finished strand shall be uniform indiameter and shall be free of imperfections notconsistent with good commercial strandingpractice.

8.3 When the strand is cut without seizings,the wire shall not fly out of position. I f a wire,or wires, flies out of position and can bereplaced by hand the strand will be consideredsatisfactory.

8.4 The strand shall not be oiled or greased.Slight rusting, provided it is not sufficient tocause pits visible to the naked eye, shaH not because for rejection.

9.Sampling

9.1 One specimen for test shaH be takenfrom each 20-ton (18-Mg) production lot offinished strand. Test specimens shall be cutfrom the outside end of reels or either end ofcqilsor reelless packs. Any specimen found tocontain a wire joint should be discarded and anew specimen obtained.

10. Test Methods

10.1 The test specimens as selected in 9.1shall be tested by the method prescribed inSu pplement V II of Methods and DefinitionsA 370.

11. Packaging and Marking11.1 The stran d shaH be furnished on r ~ l sor

in compact coils having a minimum core diameter of 24 in. (610 mm), unless otherwisespecified by the purchaser. Lengths on reels, in

coils, or in reelless packs shall be as agreedupon at the time of purchase. The strand shallbe weH protected against mechanical injury inshipping as agreed upon at the time of pur:

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chase. Each reel, coil, or reelless pack shalllhave a strong tag securely fastened to it showing the length, size, grade, ASTM Designation

. A 416, and the name or mark of the manufac

turer.11.2 Low-relaxation strand produced meet

ing the requirements of Supplement I must bespeciaHy identified.

12. Inspection12.1 The purchaser shaH state at the time of

order whether inspection by the purchaser atthe plant is required or waived. If purchaserinspection is required, the manufacturer shallafford the inspector representing the purchaserall reasonable facilities to satisfy him that thematerial is being furnished in accordance withthis speci fication. All tes ts and inspections shallbe made at the place of manufacture prior toshipment, unless otherwise agreed upon at thetime of purchase and shaH be so conducted asnot to interfere unnecessarily with the operationof the works.

13. Certification

13.1 f outside inspection is waived, a manufacturer s certification that the material hasbeen tested in accordance with, and meets therequirements of, this specification, shaH be thebasis of acceptance of the material.

14: Rejection14.1 In case there is a reasonable doubt in

the first trial as to the ability of the strand tomeet any requirement of this specification, t\\ o

additional tests shall be made on samples ofstrand from the same coil or reel, and if failureoccurs in either of these tests, the strand shallbe rejected.

SUPPLEMENT

I LOW-RELAXATION STRAND

S1. ScopeS 1 1 This supplement delineates only those

details that are peculiar to low-relaxationstrand, and to the methods of relaxationtesting related to seven-wire strand havingproperties generally as described in Specification A 416.

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S2. Applicable DocumentsS2.1 STM Standard:E 328, Recommended Practice for Stress

Relaxation Tests for Materials andStructures

Annual Book of STM Standards Parts 10 and 41.

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S3. Test ethod

S3.1 Low-relax'ation strand shall be testeqasprescribed in R e ( : o ~ m e n d e dPractice E 328.

S4. Relaxation Properties

S4.1 Low-relaxation strand shall meet .thephysical requirements of thi$ s p ~ c i f i c a t i o n lwiththe added requirement that the relaxation lossafter 1000 h under the conditions ofSS,shall benot more than 2.S % .when initially loaded to 70% of specifIed mipiml. m b r e a k i ~ gstrengtq, ornot JUore than 3 . ~% h e \ ' 1 1 0 a g ~ dto 80.:%pfspecified'. l11illimum. breakilfg strength: ,oUhestrand. . . ' .. .

) , ) '. , t .

S5. ;Yleld Strength' S ~i .Yield strength: oflow-tdaxati'on strand,

as described'in' 6.2, shaH neit be less t h ~ l D 9 b%of tnespeEifie'd' ni.lnimum breakirtg strength ofthe strand.' , "

S6. Conditions' of Relaxation:'Test

S6.1 I f required, relaxation evidence shall beprovided from the manufacturer's records of

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tests on similari y dimensioned strand of thesame grade. ' .

s6.2 The tempetature of the test piece shallbe maintained at 68 3.soF (20 2C). .'S6.3 the test piece shall not be subjected to

Idading pri'or to the relaxation test.S6.4 The initial load shall be applied un i -

fdrm1y over a period of not less than 3 min andnot more than S min, and the gage length shanbe m ~ i n t a i r i . e dconstant; load relaxation readings s h ~ i lcommence I min afterapplicatio'riofthe total load. .

S6.S Over-stressing of the test sample duringthe loading operation shall not be permitted. ;

S6.6 The duration of the test shall e 1000h or a shorter computed period extrapolated to'1000 h which can. be shown by records' toprovide similar 'relaxation values;

S6.7 T h ~test gage length shall be at least 60times the .nominal diameter. I f this gage lertgthexceeds the capaCity, of' theextensometet ortesting machine, then a minimum gage lengthof 40 times the nominal diameter may besubstituted.

TABLE 1 Breaking Strength Requirements. .

Nominal Diameterof Strand

in

,) (0.250),l'I, (0.313)Is (0.375)::Jti,(0.438). ;,

y ,(0.50,9) ,(0.6QO)

* 0.375)Jti6 (0.438)y 0.500.)

(0.60.0.)

mm

6.357.949.53

Jl.11

12.7015.24

9.53l U I

12.7015,24

B r ; ~ l d n gStrength,of Strand, Ibf(kN)

Grade 250 '

9 000 (40.0)14 500 (64.5)20'000 (89.0)27 000(120.1)

36 OOq,(160;1)54 000 (240.2), . ; ' ) ~

,. Giade 270

23 000 (102.3)3100.0.(137.9)41 jOO 083.7)58 600 (260.7)

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Nominal SteelArea of Strand, in. 2

(mm') 1':,;

0.03(\ (23.22)0.058 37.4i)0.080.(51.61j '"0.lD8 (69.,68) .

O.IM (92.90)0.216 ( 1 3 9 , ~ 5 )

0.085 (54.84)0.115 (74.19)0,153 (98.71)0..217 (140.0.0.)

Nominal Weighiof Strands,

, Ibl IQOO ft (kg/lOOO 1Jl

122 (182)197 (294)272(405) .

, ,367-(548)

; 490.(730)737 W94\.

290 (432)390. (582)520 (775)740(1102)

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~ ~ ~A 4 6

TABLE 2 Yield Strength Requirements

Nominal Diameter of Strand

in

Y-I. tO.250)Ytl,(0.313)

0.375)}-II (0.438)V 0.500)

(0.600)

0.375)}-II (0.438)V 0.500)

(0.600)

mm

6.357.949.53

Il.ll12.7015.24

9.53Il.ll12.7015.24

Initial Load, Ibf(kN)

Grade 250

900 (4.0)I 450 (6.5)

2000 (8.9)2700 (12.0)3 600 (16.0)5400 (24.0)

Grade 270

2300 (10.2)3100 13.8)4130 18.4)5860 (26.1)

Minimum Load at I Extension,Ibf(kN)

7 650 (34.0)12300 54.7)17 000 (75.6)23 000 (102.3)30 600 (136.2)45 900 (204.2)

19 550 (87.0)26.350 (117.2)35 100(156.1)49 800 (221.5)

TABLE 3 Diameter Relation Between Center and Outer Wires

Nominal Diameter of Strands

in. mm

Y I (O.25Q) 6.350/1 1 (0.313) 7.94

(0.375) 9.53V 6 (0.438) 11.11V (0.500) 12.70

(0.600) 15.24

(0.375) 9.53))1, (0.438) 11.11Y (0.500) 12.70

'(0.600) 15.24

Minimum Difference Between Center Wire Diameterand Diameter of any Outer Wire

in mm

Grade 250

0.001 0.02540.0015 0.0431

0.002 0.05080.0025 0.06850.003 0.07620.004 0.1016

Grade 270

0.002 0.05080.0025 0.06850.003 0.07620.004 0.1016

The merican Society for Testing and Materials takes no position respecting the validity o any patent rights asserted inconnection with any item mentioned in this standard. Users o f this standard are expressly advised that determination o f thevalidity o any such patel1l rights and the risk o f infringement o f such rights is entirely their own responsibility.

This standard is subject to revision at any time by the responsible technical committee and must be reviewed every fiveyears and if not revised either reapproved or withdrawn. Your comments are invited either for revision o f this standard orfor additional standards and should be addressed to STM Headquarters. Your comments will receive careful considerationat a meeting of the responsible technical committee which you may attend. I f you feel that your comments have not receivedafair hearing you should make YOllr views known to the STM Committee on Standards 1916 Race St. Philadelphia Pa.19103 which will schedule a further hearing regarding you r comments. Failing satisfaction there you may appeal to theASTM Board of Directors.

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