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Disclosure to Promote the Right To Information

Whereas the Parliament of India has set out to provide a practical regime of right to

information for citizens to secure access to information under the control of public authorities,in order to promote transparency and accountability in the working of every public authority,

and whereas the attached publication of the Bureau of Indian Standards is of particular interest

to the public, particularly disadvantaged communities and those engaged in the pursuit of

education and knowledge, the attached public safety standard is made available to promote the

timely dissemination of this information in an accurate manner to the public.

!"#$% '(%)

!"# $ %& #' (")* &" +#,-.Satyanarayan Gangaram Pitroda

Invent a New India Using Knowledge

/0)"1 &2 324 #' 5 *)6Jawaharlal Nehru

Step Out From the Old to the New

7"#1&"8+9&"), 7:1&"8+9&")Mazdoor Kisan Shakti Sangathan

The Right to Information, The Right to Live

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I S 4268: 995

ndian StandardUNCOATEDSTRESSRELIEVEDLOW

RELAXATIONSEVEN PLYSTRANDFORPRESTRESSEDCONCRETE

SPECIFICATION

UDC 666.982-426

0 BIS 1995BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

( Reaffirmed 2003 )

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Concrete Reinforcement Sectional Committee, CED 54

FOREWORDThis Indian Standard was adopted by the Bureau of Indian Standards, after the draft finalized by theConcrete Reinforcement Sectional Committee had been approved by the Civil Engineering DivisionCouncil.With the development of prestressed concrete technology and its successful application in the field ofconstruction, it became necessary to use prestressing tendons capable of developing and retaining largeconcentrated prestressing forces. This led to the development of stress relieved strand. Low relaxationstrand is further improvement in this field.The low relaxation property is achieved by a process called stabilising. This is essentially a hot stretchingprocess, in which prestressing strand is subjected to a pre-determined tension during stress-relieving heattreatment. This results in linear hardening of the steel which substantially increases the resistance to creepand thereby reduces the relaxation losses.The composition of the Committee responsible for the formulation of this standard is given at Annex A.For the purpose of deciding whether a particular requirement of this standard is complied with, the finalvalue, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordancewith IS 2 : 1960 Rules for rounding off numerical values (rev&d). The number of significant placesretained in the rounded off value should be the same as that of the specified value in this standard.

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IS 14268 : I995and shall contain not more than 0.050 percentsulphur and not more than 0.050 percent of phos-phorus, when tested in accordance withIS(Part 3) : 1987 and IS 228 (Part 9) : 1989, respec-tively.4.1.3 The wire used in the manufacture of thestrand shall be well and cleanly drawn to thespecified dimensions and shall be sound and freefrom splits, surface flaws, piping and any otherdefects likely to impair its use in the manufactureof the strand and the performance of the strand inprestressed concrete.4.2 StrandThe seven wires strand shall have a centre wire at-least 1.5 percent greater in diameter than the sur-rounding wires enclosed tightly by six helicallyplaced outer wires with a uniform length of layof atleast 12 times but not more than 16 timesof the nominal diameter of the strand. The wire inthe strand shall be so formed that they shall notfly out of position when the strand is cut withoutseizing.4.3 Joints4.3.1 There shall be no strand joints or strandsplices in any length of the completed strand, unlessspecifically permitted by the purchaser.4.3.2 During process of manufacture of individualwires for stranding, welding is permitted only priorto or at the time of last heat treatment.4.3.3 During fabrication of the seven wire strand,buttwelded joints may be made in the individualwires, provided there is not more than one suchjoint in any 45 msection of the completed strand.4.4 Treatment of Strand4.4.1 After stranding, all strands shall be subjectedto a continuous thermal-mechanical treatment toproduce the prescribed mechanical properties.4.4.2 Temper colours that may result from thethermal operation are considered normal for thefinished appearance of this strand.4.4.3 After thermo-mechanical treatment, thestrand shall be reformed into coils or wound on toreels, having core diameter of sufficient size and inany case not less than 600 mm to ensure that thestrand will lay out straight.4.5 Workmanship and FinishThe finished strand shall be uniform in diameterand shall be free from injuries, flaws and imperfec-tions. Slight rusting, provided it is not sufficient to

5 CLASSThe strand shall be either Class I or Class II depend-ing on the breaking strength of the strand given inTable 1.6 DIMENSION, TOLERANCE AND UNITWRIGIIT6.1 The nominal diameter, tolerance, nominalcross sectional area and nominal mass per unitlength of the strand shall be as given in Table 2.6.2 Physical Requirements or MechanicalProperties6.2.1 The breaking strength,and 0.2 percent proofload of the strand shall be determined in accord-ance with IS 1521: 1972 and shall be not less thanthe values specified in Table 1.6.2.2 Alternatively by mutual agreement betweenthe purchaser and the manufacturer, the load at 1.0percent extension may be determined. In this test,an initial load equivalent to 10 percent ofspecified minimum breaking strength shall be ap-plied to the test piece and a sensitive extensometerthen attached. The dial of the latter shall be ad-justed to read 0.001 mm/mm of the gauge length torepresent the extension due to the initial load. Incase of dispute, 0.2 percent proof stress shall apply.The load shall be increased until the extensometershows an extension corresponding to 1.0 percent.The load at this extension shall not be less thanthe minimum 0.2 percent proof load specified inTable 1.6.3 Elongation6.3.1 The total elongation under load shall not beless than 3.5 percent on a minimum gauge length of600 mm. The total elongation shall be measured bya suitable extensometer which is attached to the testpiece, after an initial load equivalent to 10 percentof the required minimum breaking load as specifiedin Table 1 has been applied.Following an extension of 1 percent, the exten-someter may be removed and loading continuedto ultimate failure. The elongation value is thendetermined by the movement between the jawgripping the test piece on the new base length of jawto jaw distance to which will be added the valueof 1 percent determined by the extensometer.6.4 Relaxation Properties6.4.1 Low relaxation strand, when initially loadedto 70 percent of specified minimum breakingstrength of the strand shall have relaxation lossesof not more than 1.8 percent after 100 h and not

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IS 4268: 995Table 1 Physical Properties(Cl auses 5,6.2.1,6.2.2 and 6.3)

Class

(1)

Nominal Diaof Strandmm(2)

Breakhg Sirength 0.2 96 Proof Loadof Strand

1(90 of Breaking

S~~n%h)fti

kgs fkN W(4) (5) (6)

I 9.5 89.0 9 078 80.1 8 17011.1 120.1 12 250 108.1 1102612.7 160.1 16 330 144.1 14 69815.2 240.2 2a500 216.2 22 052

II 9.5 102.3 10 434 92.1 9 39411.1 137.9 14 065 124.1 12 65812.7 183.7 18 737 165.3 1686015.2 260.7 26592 234.6 23929

Table 2 Dimensions, Tolerances and Mass of Wire Strands(Clause 6.1)

Class Nominal Diaof Strand1) 2)mmI 9.5

11.112.715.2

II 9.5

11.1

12.7

15.2

Tolerance

(3)mmkO.40LO.40kO.40kO.40+0.66-0.15+0.66-0.15+0.66-0.15+0.66-0.15

ominalArea ofStrand

(4)mm2

ominalMass of

51.669.792.9

139.4

(5)kgflun405548730

109454.8 432

74.2 582

98.7 775

140.0 1102

6.4.2 If required, the manufacturer shall provide 6.4.7 The duration of the test shall be 1000 h or arelaxation evidence from the manufacturers short computed period, extrapolated to 1 OtXl h,records of tests on similarly dimensioned strand of which can be shown by records to provide similarthe same grade. relaxation values.6.4.3 The temperature of the test piece shall bemaintained at 20 +- 2C. 6.4.8 The test gauge length should be atleast 40times the nominal strand diameter.6.4.4 The test piece shall not be subjected to load-ing prior to the relaxation test.6.4.5 The initial load shall be applied uniformlyover a period of not less than 3 minutes and notmore than 5 days and the gauge length shall bemaintained constant. Load relaxation readingsshall commence 1 minute after application of thetotal load.

7 SAMPLING AND CRITERIA FORCONFORMITY

6.4.6 Over-stressing of the test sample during theloading operations shall not be permitted.

7.1 Selection of Test SamplesTest samples of sufficient length to permit the testsfor breaking load, 0.2 percent proof load andelongation shall be cut from one end of a coilselected at random from a group of every 5 numbersof coils.

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7.1.1 The test piece shall not be detached from the Lengths on reels or reelless packs shall be as percoil or length of strand, except in the presence of agreement between the manufacturer and thepurchaser or his author&d representative. purchaser.7.1.2 Before test pieces are selected, the manufac-turer or supplier shall furnish the purchaser or hisauthor&d representative with copies of the millrecords giving number of coils in each cast withsizes as ,well as the identification marks, wherebyeach coil can be identified.7.2 Criteria for Conformity7.2.1 Should any sample fail any of the tests, byagreement between the manufacturer and the pur-chaser, two additional test samples from the sameend of the same coil shall be taken and subjectedto the test or tests in which the original samplefailed. Should both additional samples pass the testor tests, the coil from which they were taken shallbe deemed to comply with the requirements of thisstandard. Shot&d either of them fail, the coil shallbe deemed not to comply.

8.1.2 The coil shall be securely strapped to preventdistortion of the coil in transit and unless otherwisespecified the coil shall be protected against damagein transit by wrapping with hessian.8.1.3 By mutual agreement between the purchaserand the manufacturer, water soluble oil may beapplied on strands.9 MARKING9.1 Each reel or reelless pack shall carry a labelgiving the following details:

a) Indication of the source of manufacture,b) Coil number,c) Nominal diameter of strand, andd) Class, where applicable.

7.3 Should 10 percent or more of the selected coils 9.2 BIS Certification Markingfail to fulfil the requirement of this standard, theparcel from which they were taken shall be deemed 9.2.1 Each coil containing the strands may also benot to comply with this standard. suitably marked with the standard mark8 PACKING 9.2.2 The use of Standard Mark is governed by the8.1 Unless otherwise agreed to between the provisions of Bureatf ofIndian Standards Act, 19purchaser and the supplier the strands shall be and the Rules and Regulations made thereunder.supplied as indicated in 8.1.1 or 8.1.2. The details of conditions under which the licencefor the use of Standard Mark may be granted to8.1.1 Strand shall be supplied in reels or in reelless manufacturers or producers may be obtained frompacks having a minimum core diameter of 600 mm. the Bureau of Indian Standards.

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IS 14268 : 1995

ANNEX AForeword

COMMIITEE COMPOSITIONConcrete Reinforcement Sectional Committee, CED 54

ChairmanSHRIK K. MADAN&mbersSHR~Cr, R. AL~MCHANDA~~~SH~S. G. JOGLEKAR Alternate)DRK.K.AF XHANASHRIK. G. BALRAMSHRIV. NARAVAN~~WAMYAlternate)SHRIP. BHADRASHRIS. K JAIN(Alternate)SHRIS.K CHELLANISHRIRAMESHKOHLI Alternate)CHIEF ENGINEERDESIGN)SLJ~TDG NGINEER CDO) (Alternate)CHIEF ENGINEER KAD)DIR XTOR (PP-III) (Alternate)SHRID. I. DESAISHRIA. L. BHATIA Alternate)SHRIR. R. DFSA~SHRIM. S. PATHAKAlternate)SHRIS. D. DHIMANSHRIP. P: S. GUMBER Alternate)DIRECTOR HCD-NW&S)DIRECTOR N W) (Alternate)SHRIM.R.DQCT&SHRIV. C. TRICHUR Alternate)SHRIB. K DUTTASHRIV. K. GHANEKARSHRID. S. PRAKA~H AO (Alternate)SHRIP. K. GLUTASHRI . N. JAMBUSERIASHRIP. S. VENKATSU~%AMANIANAlternate)SHRIM. P. JA~UJAJOINTDIRECTORSTANDARDSB&S) CB-IIASSISTANT EFXGN NGINEER(B&S) (CS-I) (Alternate)SHRIPRUFULLAKUMARSHRIN. K SINHAAlternate)SHRIH. N. KRISHNAMURTHYDR P. C. CHOWDHURYAlternate)SHR~B.M. MADGESHRIS. B. MALE&U (Alternate)DR S. C. MowD&R. JHA (Alternate)SHRIR. K MATHURSHRIS. N. PALSHRISALILROY (Alternate)DR C. RAJKUMARDR ANIL KUMAR Alternate)DR N. S. RANGA~WAMYSHRIS. SRINIVASANAlternate)SHRIS. C. SARKAR

SHRIS. DU?TA (AZtemate)SHRI T. S NSHFUH. G. SREENATHSHFUR. JAY-N (Alternate)DR C. N. SRINIVA~ANSHR~C. R. AR~IND(Alternate)SHRI . VENKATARAMAN,Director (Civ Engg)

RepresentingCentral Public Works Department, New DelhiStup Consultants Ltd, BombayCentral Building Research Institute, RoorkeeMultiweld Wire Co Pvt Ltd, BombayBhilai Steel Plant, BhilaiUsha Martin Industries Ltd, CalcuttaCentral public Works Department, New DelhiIrrigation Department, Government of PunjabGammon India Ltd, BombayTensile Steels Ltd, BombayEngineer-in-Chiefs Branch, Army Headquarter, New DelhiCentral Water Commission, New DelhiSpecial Steels Ltd, BombaySteel Re-rolling Mills Association of India, CalcuttaStructural Engineering Research Centre, GhaziabadNational Metallurgical Laboratory (CSIR), JamshedpurKillick Nixon Ltd, BombayReasearch and Development Centre for Iron and Steel (SteelAuthority of India), RanchiResearch Designs and Standards Organizaton, Lucknow

Ministry of Transport, Roads Wing, New DelhiTor Steel Research Foundation in India, CalcuttaHindustan Construction Co Ltd, BombayThe Tata Iron & Steel Co Ltd, JamshedpurPublic Works Department, Government of UP, LucknowM. N. Dastur SKCo Pvt Ltd, CalcuttaNational Council for Cement and Building Materials, New DelhiCentral Electrochemical Research Institute, Tamil NaduMetallurgical & Engineering Consultants (India) Ltd, RanchiIRC Steelsltd, CalcuttaStructural Engineering Research Centre, MadrasC. R. Narayana Rao, MadrasDirector General (Ex-off icio Member, BIS)

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Bureau of Indian StandardsBIS is a statutory institution established under the Bureau of ndi an Standar ds Act, 1986 to promoteharmonious development of the activities of standardization, marking and quality certification of goodsand attending to connected matters in the country.CopyrightBIS has the copyright of all its publications. No part of these publications may be reproduced in any formwithout the prior permission in writing of BIS. This does not preclude the free use, in the course ofimplementing the standard, of necessary details, such as symbols and sizes, type or grade designations.Enquiries relating to copyright be addressed to the Director (Publications), BIS.Review of Indian StandardsAmendments are issued to standards as the need arises on the basis of comments. Standards are alsoreviewed periodically; a standard along with amendments is reaffirmed when such review indicates thatno changes are needed, if the review indicates that changes are needed, it is taken up for revision. Usersof Indian Standards should ascertain that they are in possession of the latest amendments or edition byreferring to the latest issue of BIS Handbook and Standards Monthly Additions.This Indian Standard has been developed from Dot : No. CED 54 ( 53 ).

Amendments Isshed Since PublicationAmend No. Date of Issue Text Affected

BUREAU OF INDIAN STANDARDSHeadquarters:Manak Bhavan, 9 Bahadur Shah Zafar Marg, New Delhi 110002 Telegrams : ManaksansthaTelephones : 3310131,33113 75 (Common to all offices)Regional Oftices : TelephoneCentral : Manak Bhavan, 9 Bahadur Shah Zafar Marg

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AMENDMENT NO. 1 JUNE 1997TOIS 14268 : 1995 UNCOATED STRESS RELIEVED LOWRELAXATION SEVEN-PLY STRAND FORPREZSTRESSEDCONCRETE - SPECIFICATION

Page 1, clause 3.1, fine 3 - Substitute central wire for centre line.( Page 1, clause 4.1.1, line 3 ) - Substitute thermomechanically for

thermally.( Page 2, clause 6.2.2, lines 9 and 10 ) - Delete the following from ninth

and tenth line and insert at the end:In case of dispute, 0.2 percent proof-stress shall apply.

Puge 3, Table 1) -Insert the following Note below the table:NOTE -The modulus of elasticity is to be taken as 195 * 10 W/mm*, unless otherwiseindicated by the manufacture.

Puge 3, Table 2) - I nsert he following Note below the table:NOTE -The nominal cross-sectional area and the nominal mass of strand are given forinformation only.

Page 3, clause 6.4.5, l i ne 3 ) - Substitute 5 minutes for 5 days.

(CED 54)

Reprography Unit, BIS,NewDelhi, ndia