is.4000.1992 high strength bolts

8/12/2019 is.4000.1992 High Strength Bolts

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FFTT pY;l??WTIndian Standard

HIGH STRENGTH BOLTSSTRUCTURES - CODE OFFirst Revision )

UDC 631-882-2 : 624-014-2-078-2

IN STEELPRACTICE

@ BIS 1992

BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARGNEW DELHI 110002

January 1992 Price Groop 6

( Reaffirmed 2003 )


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Structural Engineering Sectional Committee, CED 7

FOREWORDThis Indian Standardthe draft finalized by ( First Revision ) was adopted by the Bureau of Indian Standards, afterthe Structural Engineering Sectional Committee had been approved by theCivil Engineering Division Council.Use of high strength bolts in structural connections is fast gaining popularity over the con-ventional bolted connections. These structural connections which could be either bearing typeor friction type have rigidity or continuity comparable with what is achievable in weldedconstruction. The strength of the joint fabricated by means of these bolts is obtained bybearing or friction ( grip ) developed as a result of very high initial tension in the bolts producedby tightening the nuts to the specified bolt tension.This standard was first published in 1967. In this revision following important modificationshave been effected:

i) Bolts of property class 8.8 and 19.9 as covered in IS 3757 : 1958 High strength structuralbolts ( second revision ) have been specified.ii) In addition to friction type joints, joints subjected to tensile force only in the directionof the bolt axis and bearing type joints have been covered.

iii) In the method of tightening of bolts, the torque control method has been replaced byuse of direct tension indication device.iv) Fabrication and assembling provisions have been elaborated.v) A method for the determination of slip factor for the different surface conditions has beeninclubed.

In the preparation of this code, considerable assistance has been derived from AS 1511-1984SAA High Strength Structural Bolting Code, issued by Standards Association of Australia(SAA).


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IS 4000 1992

lndian StandardHIGH STRENGTH BOLTS IN STEELSTRUCTURES-CODE OF PRACTICE

irst Revision )1 SCOPE1 1 This standard covers the requirements forthe design, fabrication,assembly and inspectionin all types of steel structures, of structuraljoints using high strength bolts conforming toIS 3757 : 1985 CHigh strength structural bolts( second revision ) tensioned to the mini mumbolts tension specified in this code.1.2 This standard applies to high strengthbolts used in both friction type and bearingtype shear joints and for tension joints.1.3 This standard is complementary toIS 800 : 1984 Code of practice for generalconstruction on steel ( second revi sion ).Provisions not covered in this standard shallbe conforming to IS 800 ; 1984.2 REFERENCESThe Indian Standards listed in Annex A arenecessary adjuncts to this standard.3 TERMINOLOGY AND SYMBOLS3.1 TerminologyFor the purpose of this standard the definitionsgiven in 3.1.1 to 3.1.8 shall apply in additionto the nomenclature and terminology coveredin IS 8537 : 1977.3.1.1 Beari ng Type Joint s - A joint connectedwith fully tensioned high strength bolts wherejoint slip may occur so that the applied forceis transferred by shear in the bolts and bearingon the connected parts.3.1.2 Effective Interface - A common contactsurface between two load-transmitting plies,excluding packing pieces, through which thebolt passes.3.1.3 Factor of Safety - The numerical valueby which the load that would cause slip in ajoint is divided to give the maximum permissi-ble working load on the joint.

3 1 4Friction Type Joints - A joint connectedwith high-strength bolts tensioned to such abolt tension that the resultant clamping actiontransfers all the applied forces acting in thepIane of the common contact surfaces by thefriction developed between the contactsurfaces.3.1.5 Grip - The total thickness of steelsections to be held together, including packingbut excluding washers.3.1.6 Length of Bolt - The distance from theunderside of the bolt head to the extreme endof the shank including any camber or radius.3.1.7 Ply - A single thickness of steel formingpart of a structural joint.3.1.8 Proof Load - Proof stress RpoZ multipliedby the stress area of the bolt.3.1.9 Slip Factor - The ratio of the shearforce required to produce slip between twoplies to the force ( shank tension ) clampingthe two plies together.3.1.10 Snug Tight - The level of tightnessattained by a few impacts of an impact wrenchor by the full efforts of a man using a Standard/podger spanner or a spud wrench.3.2 SymbolsSymbols used in this code shall have thefollowing meaning:

d = nominal dia of bolt, in mm;e = minimium distance from edge of a.hole to the edge of a ply, in mm,

measured in the direction of a com-ponent of a force, plus half the boltdiameter. The edge of a ply shall bedeemed to include the edge of anadjacent bolt hole;f, = yield stress of the ply, in MPa;P, = tensile force on the bolt, in kN;PtO = maximum permissible tensile forcein the bolt, in kN;

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I S 4000 : 1992I = thickness of the ply, in mm;V = shear force on the bolt, in kN; and

Vob maximum permissible shear force onthe bolt, in kN.

5 DESIGN5.1 General

4 BOLT, NUTS AND WASHERS4.1 Dimensions and PropertiesBolts, nuts and washers shall conform toIS 3757 : 1985, IS 6623 : 1985 and IS 6649 : 1985respectively.

Ail connections, the rigidity of which isessential to the continuity assumed as the basisof the design analysis, shall be capable ofresisting the moments, shears and axial loadsto which they would be subjected by the designloading.5.2 Joints subject to an Applied Tensile ForceOnly in the Direction of the Bolt Axis.

4.1.1 The length of the bolt shall be calculatedby adding the allowance given in Table 1 tothe total calculated maximum grip lengthcovering maximum limits of ply thickness. Thetotal length shall be rounded off to the nexthigher nominal length given in IS 3757 : 1985.It is desirable that the designer checks in eachcase whether with the final bolt length soobtained, it is possible to tighten the nuts whenall the plates are of minimum permissiblethickness.

For joints in which the only force is an appliedtensile force in the direction of bolt axis, thetensile force on any bolt shall not exceed thevalues specified in co1 4 and 5 of Table 2.NOTES1 The tabulated value for tension P to correspondto 0.6 times the mininium bolt tension ( see Table 3)taken equal to the proof load values as stipulatedin Table 7 of IS 1367 ( Part 3 ) : 1979.

4.2 StorageCare shall be taken that bolts, nuts and washersare stored in such a way that they do notdeteriorate. They are normally supplied bythe manufacturer with a light coating of rustpreventing oil which is not detrimental andshould not be removed. In this conditionthey are ready for use and any further treat-ment at works or site is not recommended.

2 The tabulated values for shear in bearing typejoints V,,b correspond to 0.25 times the appropriateminimum tensile strength R as given in Table 3 ofIS 1367 ( Part 3 ) : 1979 multiplied by the relevantstress area of the shank or threaded portion of thebolt.5.2.1 Where fatigue conditions are involved,the tensile force on any bolt shall not exceedO-5 times the minimum bolt tension specified inTable 3.5.3 Bearing Type Joints

Table 1 Allowance for Bolt Length 5.3.1 Li mi t at ions on Beari ng Ty pe Joint sClause 4.1.1 )

Nominalizeof BoltM 16M 20M 24M 30M 36

Nominal BoltDia in mm1620243036

Allowance orGrip in mm2631364248

Shear and moment connection where slip isnot acceptable shall be designed as friction-type joints.5.3.2 Joi nt s Subj ect t o Shear Force O nl y

NOTES1 Allowance specified includes, thickness of one nutand one standard washer, to provide a safe pro-trusion of bolt end beyond the nut after tightening.Thickness of additional washers if used should beincluded in calculating the maximum total griplength.2 The allowance specified applies to friction type joints or bearing type joints where threads arepermitted in the shear plane. Higher allowancemay be required for bearing type joints wherethreads are excluded from the shear plane. Aminimum number of two free threads shall projectbeyond the inside bearing face of the nut in alljoints.

Bearing type joints subject to shear force only,and which are less than 500 mm long in thedirection of the applied shear force, shall beproportioned so that the shear force on anybolt does not exceed the maximum permissibleshear force Vat, specified in co1 6 to 9 ofTable 2.For joints greater than 500 mm long in thedirection of the applied shear force, the shearforce on any bolt shall not exceed the valuesestablished on tests. However in the absenceof the above, the following values, as appro-priate may be used:

a) 500 mm to 1200 mm longb) Over 1200 mm long

617 Vob417 Vob

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IS 4000 : 1992Table 2 Maximum Permissible Applied Forces for Joints

Clauses 5.2 and 3.2 )Nominal Sizeof Bolt Stress Area ofBolt, in mm Maximum Permissible Applied Forces in Bolts in kN~-----_-_---_-__- --c---TTension ( Pt ,in Bolts of Shear in Bearing Type Joints V,,a for Bolts ofProperty Class Property Class

Shank Thread 8.8 10.9 8.8 10.9Shank Thread Shank Thread

1) 21 3) 4) 5) 6) (7) (8) (9)M 16 201 157 56.7 78 40.2 31.4 52.3 40.8M 20 314 245 88.2 122 65.2 50.8 81.6 63.7M 24 452 353 127 176 93.8 73.2 117 91.8M 30 706 561 202 280 146 116 148 146M 36 1 017 817 294 407 211 169 264 212

5.3.3 Joi nt s Subject t o Shear and Tensil e Forces 5.4.2 Joi nt s Subj ect t o Shear Force Onl yBearing-type joints subject to shear and tensileforces shall be proportioned so that:

( pt/pto ) + ( v/vob d 1.05.3.4 Li mi tat ions of Transmit t ed Forces

In friction-type joints subject to shear forceonly in the Plane of the effective interfaces, thenumber and dispositions of high-strength boltsshall be proportioned so that the resultingforce at any boIt positions does not exceed thevalue:For bolts of all diameters, bearing force inNewtons transmitted between any bolt and anyply shall not exceed 1*2xf,x dx t. In addition,the component of a force rn newtons on a plyacting on the edge of a bolt hole in thedirection of the minimum distance toward theedge of a ply shall not exceed e f4-. t/l -4.

Slip factor x Number of effective interfaces xM;nimum bolt tensionFactor of safety

5.4 Friction Type Joints5.4.1 GeneralWhere the surfaces in contact comply with therequirements of 6.2 and the surfaces are cleanas rolled, slip factor shall be assumed as 0.35.If any applied finish, or other surface condi-tions including a machined surface is desired,slip factor used shalI be based upon testsperformed in accordance with the proceduregiven in Annex B.

NOTE - In the absence of test results, the slipfactor given in Annex C for different surface condi-tions generally adopted may be used at the discre-tion of the designer.

In the above expression, the factor of safetyshall be taken as 1.4 for structures and mate-rials within the scope of IS 800 : 1984 and forthe load combination specified therein. Noadditional factor is required to take accountof fatigue conditions. Where the effect of windforces on the structures has to be taken intoconsideration, this factor of safety may bereduced to 1.2 provided the connections areadequate when (i) wind forced are not consi-dered, (ii) wind is not the primary loading forthe purpose of design. For structures notcovered by IS 800 : 1984, the factor of safety/load factor given in the appropriate designstandard shall be used.5.4.3 Joi nt s Subj ect t o Shear and Tensil e Force

5.4.1.1 Joints shall be identified in accordancewith 5.6 and the fabrication drawings shallindicate the surface treatment required at eachjoint and whether masking of the joint isrequired during painting shall also be indicated.

An externally applied tension in the directionof the bolt axis reduces the effective clampingaction of a bolt which has been tightened toinduce shank tension. To allow for this effectthe bolt shall be proportioned to satisfy the3


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IS 4000 : 1992expression:

Calculated Shear 5Slip factor x Number of effectiveinterface( Proof load -Calculated tension x F )

Factor of SafetyThe value of factor F shall be taken as 2-O if theexternal tension is repetitive and 1.7 if non-repetitive.54.4 L im itat i on of Tran smi tted ForcesThe shear force between the bolt and ply shallbe limited to the value determined in accor-dance with 5.3.4.5.5 Packing5.5.1 Friction Type JointsFor friction type joints no additional factor isrequired to take account of packings within ajoint.5.5.2 Bearing Type JointsIn bearing-type jonts where high-strength boltsthrough a packing plate are required to carrycalculated shear, the number of bolts required,determined by calculation, shall be increasedabove the numbers required by normal calcu-lation by 2.5 percent for each 2 mm thicknessof packing in excess of 6 mm. For double shearconnection with packing on both sides of amember, the increase in number of bolts shallbe determined by the thickness of the thickerpacking provided.5.6 IdentificationThe designer shall indicate on drawings theposition of all high-strength structural boltsand shall state the type of joint that is, frictiontype joint or bearing-type joint. In the absenceof such designation, the fabricator shall assumesuch joints to be bearing-type joints.6 FABRICATION6.1 Holes in MembersUnless specified otherwise, the diameter of ahole shall be 1.5 mm and 2.00 mm more thanthe nominal bolt diameter for bearing typejoints and friction type joints respectively.6.2 The edge distance for any hole and thedistance between holes ( pitch ) shall conformto the requirements of IS 800 : 1984.

6.3 Holes shall he provided by drilling only forall dynamically loaded connections and alsofriction type joints and by any of the followingmethods (a), (b) or (c) for other type of joints:a)9C)

Dr i l l ing - Holes drilled full size.Sub pun chi ng - Holes sub-punched 3 mmundersize and reamed to size.Punchin g I I size - Holes punched fullsize provided:

i) The joint is not located at a plastichinge,ii) The material shall not have a yieldstress ( fY ) in excess of 360 MPa,and

iii) Thickness of individual members doesnot exceed 12 mm.

6.3.1 Oversize and Sl otted H olesa)b)Cl

Oversize holes shall not exceed 1.25 d ord+8mm,Short slotted holes shall not exceed d+2mm in width and 1.33 d or d+lO mm inlength, andLong slotted holes shall not exeed d + 2mm in width and 2.5 d in length.

6.3.2 L im itat i on on Use4

b)

4

Oversize holes - Oversize holes may beused in any or all plies of bearing-typeand friction-type connections providedhardened washers are installed over theoversize holes.Shor t slott ed holes - Short slotted holesmay be used in shear-type connections inany or all plies of friction-type andbearing-type joints provided-hardenedwashers are installed over the exposedholes.In friction-type joints the slots may beused without regard to direction of load-ing but in bearing-type joints slottedholes may be used only where the joint isnot eccentrically loaded, where the boltscan bear uniformly and where the slotsare normal to the direction of the load.Long slotted holes - Long slotted holesmay be used in shear-type connectionsonly in alternate plies of either friction-type or bearing-type joints provided aspecial washer of coverplate, not lessthan 8 mm thick, is used to completelycover all exposed long slotted holes.

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IS 4000 : 1992.In friction-type joints, long slotted holesmay be used without regard to directionof loading provided an additional 33percent more bolts are used than neededto satisfy the provisions covered under5.4 but in bearing-type joints, long slottedholes may be used only where the joint isnot eccentrically loaded, where the boltscan bear uniformly and where the slotsare normal to the direction of the load.

6.4 Preparation of Surfaces in Contact6.4.1 GeneralAll oil, dirt, loose scale, loose rust, burrs andany other defects on the surfaces of contactwhich will prevent solid seating of the partsshall be removed.6.4.2 Friction-type JointsFor friction-type joints the contact surfacesshall be clean Gas-rolled surfaces or equivalentand in addition to meeting the provisionscovered under 6.4.1 shall be free from paint,lacquer, galvanizing or other applied finish,unless otherwise specified or approved by thecompetent authority.6.4.3 Bearmg-type JointsFor bearing-type joints, an applied finish onthe contact surfaces shall be permitted.7 ASSEMBLY7.0 GeneralNo joint shall be assembled for bolting untilthe contact surfaces have been inspected andapproved by the competent authority.7.1 Procedure7.1.1 Number of WashersEach bolt and nut shall be assembled with atleast one washer. A washer shall be placedunder the rotating component.

7.1.3 Pl acemenf of Nu t sThe nut should be placed so that theymarkspecified in IS 6623 : 1985 to identify a high-strength nut is visible after tightening.7.1.4 PackingPacking shall be provided wherever necessaryto ensure that the load-transmitting plies are ineffective contact when the joint is tightened tothe snug-tight condition as defined in 7.2.2 (a).All packings shall be of steel with a surfacecondition similar to that of the adjacent plies.7.1.5 Al ignment of PartsThe holes in the parts to be joined shall bealigned to permit the bolts to be positionedwithout damage to the threaded portion of thebolt. Drifting to align holes shall not distortthe metal or enlarge the holes.7.1.6 Tightening,PatternSnug-tightening and final tensioning of the boltsshall proceed from the stiffest part of the jointtowards the free edges.High strength bolts may be used temporarilyduring erection to facilitate assembly, but if soused they shall not be finally tensioned until allbolts in the joint are snug-tight in their correctsequence.7.1.7 RetensioningBetensioning of bolts which have been fullytensioned shall be avoided wherever possible. Ifretensioning must be carried out it shallonly be permitted once and only when thebolt remains in the same hole in which itwas originally tensioned and with the samegrip.Under no circumstances shall bolts which havebeen fully tensioned be reused in another hole.7.2 Method of Tensioning

7.1.2 Tapered Washers 7.2.1 GeneralWhere the angle between the axis of the bolt The method of tensioning shall be in accordanceand the joints surface is more than 3 degree off with 7.2.2 or 7.2.3.normal, a tapered washer shall be used againstthe tapered surface. The non-rotating compo- In the completed connection all bolts shall havenent shall preferably be placed against the at least the minimum tension specified intapered washer. Table 3.

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Is4ooo:I992Table 3 Minimum Bolt Tension

( Clauses 7.2:1, B-l.2 and D-2.2 )Nominal Sizeof Bolt

M 16M 20M 24M 30M 36

Minimum Bolt Tension in kN forBolts of Property ClassC---h-----y8.8 10.994.5 130

147 203212 293337 466490 678

7.2.2 Part- turn M ethod of Tensioni ngTensioning of bolts and nuts by the part-turnmethod shall be in accordance with the follo-wing procedure:

a)

b)

c)

7.2.3

On assembly, all bolts and nuts in thejoint shall be first tightened to a snug-tight condition to ensure that the load-transmitting plies are brought intoeffective contact.After completing this preliminary tighte-ning to snug-tight location marks shallbe established to mark the relativeposition of bolt and nut and to controlthe final nut rotation specified in Table 4.Observation of the final nut rotation maybe achieved by using marked wrenchsockets, but location marks shall bepermanent when required for inspection[ ( see B-2 (a) 1.Bolts shall be finally tensioned by theamount specified in Table 4. During thefinal tensioning the component notturned by the wrench shall not rotate.Tensioning by Use of Di rect -t ension_.Indicat ion

Tensioning of bolts and nuts using a direct-tension indication device shall be in accor-dance with the manufacturers instructlons andthe following procedure:a)

b)

On assembly, all bolts and nuts in thejoint shall be first tightened to a snug-tight condition as described in 7.2.2(a).After completing this preliminary tight-ening to 120 240< 120 > 120 < 240< 160 > 160 < 350< 160 > 160 < 3.50Q 160 > 160 < 350

8 INSPECTION

1 Nut rotation is rotation relative to the bolt,regardless of the component turned.NOTES1 Tolerance on rotation: one-sixth of a turn (60degrees ) over : no under tolerance.2 The bolt tension achieved with the amount of nutrotation specified in Table 4 will be at least equalto the minimum bolt tension.

8.1 Visual InspectionBolts and nuts which on visual inspection showany evidence of physical defects shall beremoved and replaced by new one.8.2 Tensioning ProceduresInspection shall ensure that the selectedtensioning procedure has been correctly appliedand that all bolts are fully tensioned. This willrequire inspection both at the snug-tight stageand when bolts are fully tensioned. The follo-wmg methods shall be used to check that allbolts are fully tensioned:

a) In Part- turn Tensioni ng -by ensuring thatthe correct part-turn from the snug-tightposition can be measured or observed.When the subequent use of an inspectionwrench is not required by the supervi-sing engineer, the bolts and nuts shallcarry permanent location marks.

b) In Di rect- Tension I ndicati on Tensioning - _by ensuring that the manufacturersspecified tensioning procedure has beenfollowed and that the development ofminimum bolt tension is indicated bythe tension indication device.NOTE - The use of a torque wrench for inspectionis considered suitable only to detect gross under-;,n;.xngg. A procedure for such use IS detailed in

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ANNEX AItem 2 )

LIST OF INDIAN STANDARDS REFERRED

zS 4008 : 1992

ISNo Tit le I S No.1367 Technical supply conditions for 6623 : 1985( Part 3 ) : 1979 threaded steel fasteners: Part 3Mechanical properties and testmethods for bolts, screws and 6649 . 1985studs with full loadability3757 : 1985 Specfication f~ol~~gh strengthstructural ( second 8537 : 1977

revision )

Ti t leSpecification for high strengthstructural nuts (f irst revision )Specification for hardening andtempering washers for highstrength structural bolts andnuts (j St r evisi on )Nomenclature and terminologyof fasteners

ANlWX BClause 5.4.1 )

STANDARD TEST FOR EVALUATION OF SLIP FACTORB-l TEST SPECIMENSB-l.1 FormThe standard test specimen is a symmetricaldouble coverplated butt joint as shown in Fig. 1.It is suggested that use of M 20 bolts will proveto be most convenient, with use of 25 mm innerplates and 12 mm outer plates. It is essentialthat both inner plates are identical in thicknesswhich can be controlled by cutting adjacentpieces from one plate.B-l.2 Assembly and MeasurementCare must be taken in assembiing the specimento ensure that neither bolt is in bearing in thedirection of loading, and that the surfaceconditions of the friction in the faces is maiu-tained in the condition to be achieved inthe field. For example, if rt is necessary tomachine the ends of the inner plates to fit intothe loading machine grip, machining oil shouldnot be allowed to contaminate the surfaces.Preferably, bolts shall be tensioned in the samemanner as that to be used in practice and shalldevelop at least the minimum bolt tensionspecified in Table 3.

.Between csnug-tightening and final tensioningthe bolt extension shal,l be measured using a

displacement transducer with a resolution of0.003 mm or finer. Bolt tension shall be ascer-tained from a calibration curve determinedfrom load cell tests of at least three bolts ofthe test batch. In establishing the calibrationcurve, the bolt grip through the load cell shallbe as close as practicable to that used in thespecimens, the same method of extensionmeasurement and tensioning employed, and thecalibration based on the mean result. For thepurposes only of these tests, the initial snug-tight condition shall be finger tight.Alternatively, when a bolt tension load cell isnot available, the bolts shall be tensioned to atleast 80 percent and not more than 100 percentof their specified proof loads, and the tensioninduced in the bolts calculated from the for-mula:

R = E X A X l-3me, i)b + c/ 2+ A 8

whereR = tension induced in the bolt, in kNE = youngs modulus = 200 000 MPa

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Is 4000 1992

LO OR 2d) min

LOAD

J_ 120 OR 6d)min - LO OR 2d) minI I ,-12 OR :+,I min

1.25 OR d+6) min

L60 OR. 3d) min_ ROLL ING DIRECTION _

OF PLATENOTES1 Holes in plates:Cover plates . . . . . . . . . . . . . . . . . 22 mm or +2 mm

Inter plates . . . . . . . . . . .*...... 23 mm or ( d+3 ) mm2 Length and width of inner plates outside of test section may be raised to suit thelaboratorys testing facilities.3 Dimensions are shown for the ( suggested ) use of M 20 bolts. Dimensions inparentheses are for use of bolts with nominal diameter din mm, whxh should be notless than 16 mm.4 All dimensions are in miilimetres.

FIG. 1 STANDARDTEST SPECIMEN

a - length of the unthreaded portion of thebolt shank contained within the gripbefore tensioning, in mmA = cross-sectional area of the unthreadedportion of the bolt, in mmeb = length of the threaded portion of thebolt contained within the grip1 beforetensioning, in mmc = thickness of the nut, in millimetresAl= tensile stress area of the bolt as tabu-lated in Table 2, in mm

in millimetres. The final measurementshall be made immediately prior totesting. A micrometer or other trans-ducer with resolution achieving O-003mm or finer is required.NOTE - It is not necessary for both bolts in theone specimen to have identical tension.

B-l.3 Number of SpecimensTest on at least three specimens shall be under-taken, but five is preferred as a practicalminimum number.

A = the measured total extension of the ~-2 INSTRUMENTATIONbolt when tightened from a finger-tightcondition to final tensioned condition, Two pairs of dial gauges or other displacementtransducers having an effective resolution4n this context, the grip includes the washer thick- achieving 0.003 mm or finer shall be symmetri-ness. tally disposed over gauge lengths of 60 mm

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( 3d) on each edge of the specimen so as tomeasure the deformation between the innerplates from the bolt positions to the centre ofthe cover plates. The deformation of eachhalf of the joint shall be taken as the mean ofthe deformation at each edge. The deformationSO measured is therefore the sum of the elasticextension of the cover plates and any slip at thebolt positions. It is essential that transducersare securely mounted since they may be shockloaded as slip occurs.R-3 METHOD OF TESTING

a) Type of Loading - Specimens may betested only by tensile loading.b) Loading Rate - Up to the silp load, forceshall be applied in increments exceedingneither 25 kN nor 25 percent of the slipload of the joint assuming a slip factor of0.35 and calculated bolt tension. The

loading rate should be approximatelyuniform at not more than 50 kN/minwithin each load increment. Slowerloading rates are preferred. Each loadincrement should be applied after creepat constant load due to the preceding loadincrement having effectively ceased.Since slip will in all probability occur at onebolt position before the other, it is clear thatthe first bolt may slip into bearing before theslip load at the other bolt position is attained.After attainment of the slip load at one boltposition, the loading rate and increment sizemay be adjusted at the discretion of theoperator.R-4 SLIP LOAD J,Slip is usually well defined and easily detectedby the operator when a sudden increase indeformation occurs. One or more sharp clearlyaudible reports may also be heard. However,with some types of surface, and occasionally

IS 4000 : 1992with normal surfaces, the incidence of slip isnot so well defined. In these cases the loadcorresponding to a slip of 0.13 mm shall be usedto define the slip load.R-5 SLIP FACTORThe slip factor p to be used in design is givenby:

Pwhere

k

= k ( ,,rn - 1.64 s) . . . . . . . . . . . . . . . . . ( 2 )

= 0.85 when 3 specimens are tested.

P

s

Pi

P*i

0.90 when 5 or more specimens aretestedmean value of slip factors for alltests, and is

1 2N.-2N 2 1 Pi . . . . . . . . . . . . . . . . ( 3 )i=standard deviation of slip factorsfor all tests, and is

1 2N2N- 1 i=zl(pi-~~) 3. . . . . . . . . . . . . . . . . . 4 )1 x PBi- 2 ( >__Ri . . . . . . . . . . . . . . . . . . ( 5 )

number of specimens tested, eachproviding two estimates of Cc,sayPI and pi+1measured slip load at the positionof the ith bolttension induced in the ith bolt bythe tensioning as calculated fromformula (1)

However, if the value of p calculated fromformula (2) above is less than the lowest of allvalues of pi, then p may be taken as equal to belowest value Of jLi*


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IS 4000 : 1992ANNEX CClause 5.4.1 )

RECOMMENDED SLIP FACTORS

Treatment of Surf ace Sli p Fact or, po-20o-50

Treatment of Surf ace Slip Factor, pSurface not treatedSurface blasted with shot or gritwith any loose rust removed,no pitting

Surfaces blasted with shot orgrit and painted with ethyl-zinc silicate coat ( thickness60-80 /.Lm

o-30

Surfaces blasted with shot or gritand hot-dip galvanizedSurfaces blasted with shot or gritand spray-metallized withzinc ( thickness 50-70 p,,, )Surfaces blasted with shot orgrit and paintedzinc silicate coat30-60 /+, )

with ethyl-( thickness

o-10 Surfaces blasted with shot orgrit and painted with alcali-zinc silicate coat ( thicknesso-30

O-25

0.30

0-80 pm )Surfaces blasted with shot orgrit and spraymetallizedwith aluminium ( thickness

> 5o Pm >

o-50

NOTE-The contact surfaces shall not be sandblasted.

ANNEX DClause 8.2, Note )

INSPECTION OF BOLT TENSION USING A TORQUE WRENCH

D-l GENERALThe correlation between the torque determinedto fully tension a calibration specimen and thatwhich will be required on a bolt nut assemblyinstalled in a structural joint, will be materiallyeffected by such factors as:

a) the exact equivalence of thread andbearing surface condition and lubrication;b) the occurrence of galling during tension-ing; andc) the time lapse between tensioning andinspection.

Within these limitations, the procedure givenherein may be considered the most practicalmethod for an independent assessment ofwhether the specified bolt tension has beenachieved.

D-2 CALIBRATIOND-2.1 InspectionWrenchThe inspection wrench may be either a hand-operated or adjustable-torque power-operatedwrench. It shall be calibrated at least onceper shift or more frequently if the need toclosely simulate the conditions of the bolt inthe structure so demands.The torque value determined during calibrationmay not be transferred to another wrench.D-2.2 SamplesAt least three bolts, desirably of the same size( minimum length may have to be selected tosuit the calibrating device ) and condition asthose under inspection shall be placed indivi-dually in a calibrating device capable of indica-ting bolt tension. A hardened washer shall beplaced under the part turned.

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IS 4000 : 1992

Each calibration specimen shall be tensioned inthe calibrating device by any convenient meansto the minimum tension shown for that diameterin Table 3. The inspection wrench then shallbe applied to the tensioned bolt and the torquenecessary to turn the nut or bolt head 5 degrees( approximately 25 mm at 300 mm radius ) inthe tensioning direction shall be determined.The average torque measured in the tests of atleast three bolts shall be taken as the jobinspection torque.D-3 INSPECTIONBolts represented by the sample prescribedin D-2.2 which have been tensioned in thestructure shall be inspected by applying, in thetensioning direction, the inspection wrench andits job inspection torque to such proportion ofthe bolts in the structure as the supervisingengineer shall prescribe.

NOTE -For guidance it is suggested &hat a suitablesample size would be 10 Dercent of the bolt. but notless than two bolts in kach connection a;e to beinspected.

D-4 ACTIONWhere no nut or bolt head is turned by the job-inspection torque, the connection shall beaccepted as properly tensioned.Where any nut or bolt head is turned by theapplication of the job-inspection this torqueshall then be applied to all other bolts in theconnection and all bolts whose nut or head isturned, by the job inspection torque shall betensioned and re-inspected. Alternatively, thefabricator or erector at his option may retensionall of the bolts in the connection and thenresubmit the connection for inspection.

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Standard MarkThe use of the Standard Mark is governed by the provisions of the Bureau of I ndianStandards Act, 1986 and the Rules and Regulations made thereunder. The Standard Markon products covered by an Indian Standard conveys the assurance that they have beenproduced to comply with the requirements of that standard under a well defined systemof inspection, testing and quality control which is devised and supervised by BIS andoperated by the producer. Standard marked products are also continuously checked byBIS for conformity to that standard as a further safeguard. Details of conditions underwhich a licence for the use of the Standard Mark may be granted to manufacturers orproducers may be obtained from the Bureau of Indian Standards.


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Borean of Iodiau StandardsBIS is a statutory institution established under the Bureau of I ndian Standards Act, 1986 topromote harmonious development of the activities of standardization, marking and qualitycertification of goods and attending to connected matters in the country.CopyrightBIS has the copyright of all its publications. No part of these publications may be reproducedin any form without the prior permission in writing of BIS. This does not preclude the free use,in the course of implementing the standard, of necessary details, such as symbols and sizes, typeor grade designations. Enquiries relating to copyright be addressed to the Director( Publications ), BIS.Revision of Indian StandardsIndian Standards are reviewed periodically and revised, when necessary and amendments, ifany, are issued from time to time. Users of Indian Standards should ascertain that they are inpossession of the latest amendments or edition. Comments on this Indian Standard may besent to BIS giving the following reference:Dot : No. CED 7 ( 4722 )

Amendments hued Since PublicationAmend No. Date of Issue Text Affected

BUREAU OF INDIAN STANDARDSHeadquarters :Manak Bhavan, 9 Bahadur Shah Zafar Marg, New Delhi 110002Telephones : 331 01 31. 331 13 75 Telegrams : Manaksanstha

( Common to all Offices )Kegional Offices : TelephoneCentral : Manak Bhavan, 9 Bahadur Shah Zafar MargNEW DELHI 110002 I 311 01 31331 13 75Eastern : l/14 C. I. T. Scheme VII M, V. I. P. Road, ManiktolaCALCUTTA 700054 37 86 62Northern :Southern :Western :Branches :

SC0 445-446, Sector 35-C, CHANDIGARH 160036C. I. T. Campus, IV Cross Road, MADRAS 600113Manakalaya, E9 MIDC, Marol, Andheri ( East )BOMBAY 400093

53 38 43235 02 16

6 32 92 95AHMADABAD, BANGALORE, BHOPAL, BHUBANESHWAR, COIMBATORE,FARIDABAD, GHAZIABAD, GUWAHATI, HYDERABAD, JAIPUR, KANPUR,PA-WA, THIRUVANANTHAPURAM.

is.4000.1992 high strength bolts

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