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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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15 3370 Part 2 : 2009

~ ~ g o l ~ i i r ~ r ~ _ fl T 2 M i ~ d Q s le ~ q ~ ~

Indian StandardCONCRETE STRUCTURES FOR STOR GE OF

LIQUIDS CODE OF PR CTICEPART 2 REINFORCED CONCRETE STRUCTURES First Revision

ICS 23.020.01; 91.080.40

BIS 2009URE U IND I N ST ND RDSM N K SH V N . 9 B H D tJR SH H ZAFAR MARG

NEW DELHI 110002

June 200 J PriaGroup

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Cement and Concrete Sectional Committee, CED 2

FOREWORDThis Indian Standard Part 2) First Revision) was adopted by the Bureau of Indian Standards. after the draftfinalized by the Cement and Concrete Sectional Committee had been approved by the Civil Engineering DivisionCouncil.This standard was first published in 1965. The present revision has been taken up with a view to keeping abreastwith the rapid development in the field of construction technology and concrete design and also to bring furthermodifications in the light of experience gained while applying the earlier version of this standard and theamendmentissued .The design and construction methods in reinforced concrete and prestressed concrete structures for the storageof liquids are influenced by the prevailing construction practices, the physical properties of the materials and theclimatic condition. To lay down uniform requirements of st ruc tu re s for the s to ra ge of liquids giving dueconsideration to the above mentioned factors, this standard has been published in four parts, the other parts in theseries are:

part 1) : 2009 General requirements Part 3 : 1967 Prestressed concrete structures Part 4 : 1967 Design tables

While the common methods of design and construction have been covered in this standard, for design of structuresof special forms or in unusual circumstances, special literature may be referred to or in such cases special systemsof design and construction may be permitted on production of satisfactory evidence regarding their adequacyand safety by analysis or test or by both .In this standard it has been assumed that the design of liquid retaining structures, whether of plain, reinforced orprestressed concrete is entrusted to a qualified engineer and that the execution of the work is carried out under thedirection of a qualified and experienced supervisor.All requirements of IS 456 : 2000 Code of practice for plain and reinforced concrete fourth revision) andIS 1343 : 1980 C od e of practice for prestressed concrete first revision) , in so far as they apply, shall be deemedto form part of this standard except where otherwise laid down in this standard. For a good design and constructionof structure, use of dense concrete, adequate concrete cover, good detailing practices, control of cracking, goodquality assura nc e m ea su re s in line with IS 456 and good c on st ru ct io n pr ac ti ce s p art icu la rl y in r el at io n toconstruction joints should be ensured.This revision incorporates a number of important modifications and changes, the most important of them being:

a) Scope has been clarified further by mentioning exclusion of dams, pipes, pipelines, lined structures anddamp-proofing of basements;

b) A new sub-clause on loads has been added under the c la us e on design;c} Regarding method of design, it has been specified that one of the two alternative methods of design, that

is, limit state design and working stress design may be used; andd} Provision for crack width calculations due to temperature and moisture and c ra ck width in mature

concrete have been incorporated as Annex A and Annex B, respectively.The composition of the Committee responsible for formulation of this standard is given in Annex C.For the purpose of deciding whether a particular requirement of this standard is complied with, the final value,observed or calculated, ex pre ssi ng the results of a test or analysis, shall be rounded of f in accordance withIS 2 : 1960 Rules for rounding of f numerical values revised) . The number of significant places retained in therounded of f value should be the same as that of the specified value in this standard.

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IS 3310 Part2) : 2009

Indian StandardCONCRETE STRUCTURES FOR STORAGE OFLIQUIDS - CODE OF PRACTICE

PART2 REINFOR E ON RETE STRUCTURES First Revision

2 REFERENCESThe following standards contain provisions, whichthrough reference in this text. constitute provisions ofthis standard. At the time of publication. the editionsindicated were valid. All standards are subject torevision and parties to agreements based on thisstandard are encouraged to investigate the possibilityof applying the most recent editions of the standardsindicated below:

1 SCOPE1.1 This standard Part 2) lays down the requirementsapplicablespecificallyto reinforcedconcrete structuresfor the storage of liquids, mainly water. Theserequirements are in additionto the generalrequirementslaid down in IS 3370 Pan 11.2 This standard does not cover the requirements forreinforced and prestressed concrete structures forstorage of hot liquids and liquids oflow viscosity andhigh penetrating power like petrol. diesel oil. etc. Thisstandard also does not cover dams, pipes. pipelines.lined structures and damp-proofing of basements.Special problems of shrinkage arising in the storageof non-aqueous liquid and the measures necessarywhere chemical attack is possible are also not dealtwith. The recommendations. however. may generallybe applicable to the storage at normal temperatures ofaqueous liquids and solut ions which have nodetrimental action on COncrete and steel or wheresufficient precautions are taken to ensure protectionof concrete and steel from damage due to ,action ofsuch liquids as in the case of sewage.

/SNo. 56:20001786 : 2008

3370 Part 1) : 2009 Part 4) :1967

tleCode of practice for plain andreinforced concrete fourth revisionSpecification for high strength barsand wires forconcrete reinforcementfourth revisionConcrete structures forthe storageofliquids - Code of practice:General requirements first revisionDesign tables

3 GENERAL REQUIREMENTSDesign and construction of reinforced concrete liquidretainingstructuresshall comply withthe requirementsof IS 3370 Part I) and IS 456 unless otherwise laiddown in this standard.4 DESIGN4.1 GeneralProvisionsshall be made for conditions of stressesthatmayoccur in accordance with principlesof mechanics.recognized methods of design and sound engineeringpractice.In particular. adequate consideration shall begiven to the effects of monolithic construction in theassessmentof axial force. bending moment and shear.4.2 LoadsAllstructures required toretainliquids shouldbedesignedfor both the full and empty conditions. and theassumptions regarding thearrangements of loading shouldbe such as to cause the most criticaleffects. For loadcombinations, waterload shall be treatedas dead 10a 1Liquid loads should allow for the actual density of thecontained liquid and possible transientconditions. forexample. suspended or deposited silt or grit whereappropriate. For ultimate limit state conditions andworking stress design, liquid levels should be taken tothemaximumlevel the liquidcan rise assumingthattheliquidoutletsare blocked. For serviceability. limit stateconditions, the liquidlevelshouldbe takento theworkingtop liquidlevel or the overflowlevel as appropriate toworkingconditions. Allowanceshould be made for theeffects of any adverse soil pressures on the walls.accordingto thecompactionand/orsurchargeof thesoiland the condition of the structure during constructionand in service. No relief should be given for beneficialsoil pressure effects on the walls of containmentstructures in the full condition. Loading effects due totemperature occurs when thermal expansion of a roofforces the walls of an empty structure into thesurrounding backfill causing passivesoil pressure. Thiseffectcanbe reducedby providinga slidingjointbetweenthe top of the wallandunder side of the roof which maybe either a temporary free sliding joint that is not cast

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IS 3370 Part 2) : 2009

Table 1 Permissible Coacrete Stresses inCalculations Relating to ResistaDceto CrackingChuues 4.5.I(c). 4.5.2.1 and 6.3(b)]

i) M2S 1.3 Uii MJ 1.5 2.0iii) M3S 1.6 2.2jy M40 1.1 2.4y) M4S 2 0 26yj MSO 2 2.1

NOTE - The YIIues of sbar JlrcsI in sUll be1iY= in IS4 6.

that in matureconcrete shall be calculated as given inAnnex B.4 4 3 Crackwidthsforreinforced concretemembersindirect tensionand flexural tensionmayhedeemedto besatisfactory if steel S reSS underserviceconditionsdoesnot exceed 115 mm2 for plain bars and 130 mm2for high strength deformed bars.4.5 Working Stress Design4.5.1 BasisofDesignThe design of members shall be based on adequateresistance to cracking and adequate strength .Calculationof stresses shall be basedon the followingassumptions:

a) At any cross-section plane section remainsplane after bending.b) Both steelandconcreteareperfectly elasticandthe modularratiohas the valuegiven in IS456.

c) In calculationof stresses. for bothflexuralanddirect tension or combination of both)relating to resistance to cracking. the wholesection of concrete including the covertogether with the reinforcement can be takeninto account provided the tensile stress inconcrete is limited to Table Id) In strength calculations the concrete has notensile strength.

...5.2 ermissible Stresseson oncrete4.5.2.1Resistance to crackingFor calculations relating to the resistance to cracking.the permissible concrete stresses shall conform to thevalues specified in Table I Altbough cracks maydevelopinpractice. compliancewithassumptiongivenin 4.5.1(c) ensures that these cracks arenot excessive.

Pcnaiulble COllUde StrataNI J_-----ANo

into a fixed or pinned connection. or a permanentlyslidingjoint of IbSC:SSed limiting friction . M o v ~ ~ ofa roofmayoccuralsowherethereissubstantial vanauonin the temperature of the containedliquid.Wherea roofis rigidlyconnected 10 a wall thismayleadtoadditionalloading in lhe wall that should be considered in thedesign. Earth coveringon reservoirroofmaybe takenasdead load . but due account should be taken ofconstruction loads from plant and heaped earth whichmayexceeo the intendeddesign load.Thejunctions betweenvariousmembers(betweenwalland floor) intended to be constructed as rigid shouldbedesignedaccordinglyand effect ofcontinuityshouldbe accounted in design and detailing of each member.4.3 Methods of DesignOne of lhe two alternative melhods of design givenin 4.4 and4.5 for design of water retainingstructuresshan be followed:

Additionalprovisionsfordesignof floors.wallsandroofsaregiven in5. 6 and7 respectively.Structuraldements that are not exposed to the liquids or tomoist conditions shall be designed in accordancewith IS456...... Umit State Desip .1 Limit State Req ,irtmtlltsAllrelevantlimitStaleS shallbeconsidered in thedesignto ensurean adequate degree of safetyand serviceability.1 1 Limit stlUe ofcollapsThe recommendations given in IS 456 shan befollowed....... 1.1 Limitstales o f serviceability

a) Deflection - The limits of deflection shaIbe as per IS 456.b) Croding - The maximumcalculalcd surfacewidthof cracks fordirect tensionand flex ureor restrained temperatureaodmoisture effectsshall notexceed 0.2 mmwithspecifiedcover.

4.4.1.3 Partial safety factorThe recommendationsgiven in IS456 forpartial safetyfaet0r5for s r v ~ i l i t y shall be followed. 4 1 Basis01 DesignDesignanddetailing of reinforcedconcrete shall be asspecified in Section S of IS 456 except thal 37.1.1 ofIS456 shall DOl apply.

O C r a d ~ h sCrack widths due to the temperature and moistureeffects sha J be calculated as given in Annex A and

2

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IS 337. Pari 2) : 1009

lable3 Pel ble Shear Stress ID Co9CrfleClaust 4.5.2.2. and Tablt 2)

4.S.3 hrmissible Stresses in Stee4.5.3.1 Resistance crac1illgThe tensile stress in the steel willnecessarily be limitedby the requirement that the permissible ensile Slres5in thecoeerete is nOlexceeded; 50 he tensile suess in

4.5.2.2 t ~ n t h calculationIn strength calculations. the permissible concretestresses shall be in accoo:Iance wilbTable 2 and Table 3.

lable2 Permissible Stres.Ws ia CoocftteAll values are in N/mm 2

i) TCIIIilc __ . .-b a s li S 130lIIIlb 0iftlCI IaIIian~ I I dii) CompIasiYe III CSS il l 12$ l.a001_ subjec:lecl todim;lload

Sl ofSfna SCftI I n1aIIIi1IIrs r rNa. d f_t A .r HiPSIftIIIdlIMI RAlUIldMilclSlDdBm Dd:Jrnxld BI n I) (2) (3) (4)

4.5.3.2 Strrngth calculationsFor strenglb calculations. the: perm issible stresses insteel shall conform to the values specified in Table 4.

c) The tank. is to be lI)CCjonly for the stora&e ofwater or aqueous liquids It or near ambienttemperature an d the concrete neverdnes out,and

d) A de qu at e p re ca ut io ns a re taken to avoidcracking o f th e c on cr ete d ur in g th ecoeseuetion period and until the lanle is putinto usc.

T.bIe .. Pel misaible StreIRs ia SledReinfonaneat for Streaeth

a) The reinforcement provided ~ nOl less thanIbal specified in 8.b) The recommendations of the standard with

regard to the provis ion of movement joinuand for a suitable 51iding layer benealb thetank. given in IS 3370 Part I) arc compliedwith.

steel shill be equal to the product of modular ratio ofsteel and concrete, and the corresponding permissibletensile stress in concrete.

.5.4.1 Shrinlease stresses may, however. be rcquin:dto be calculated in special cases. when a shrinkagecoefficienl of 300)( I()-6maybe assumed...5....2 W he re r es er vo ir s a re p ro te ct ed with anincemal impermeable lining. consideration shouldbe liven to the possibi li ty of concrete eventually.dry in , OUI. Unless it is establi5bc:d on the basis oftests or experience Ibat th e linin, has adequate crackbridaing properties. allowance for the increasedeffect of dryinl shrinka,e should be made in hedesign.

4.5.4 S ~ S S t S Dw toMoisnlre orTt 'IWtUttllYClttJrtgesNo separate cak:ulation is requin:d for stres.es du e tomoisture or temperature change in the concreteprovided that:

Gradtof PftWillibk Straa Ie r--....,CMCI de C_pcuIioII Stra l i . IolldA (A ftf1IIe) lo rr \ I IahI Ban 8cDding DiIUl TrtUIoea . a.. r..(2) (3) (4) (S)

M25 I .S 6.0 0.9M30 10.0 1.0 1.0MJS II .S 9.0 1.1M40 13.0 10.0 1.2M4S 14.S 11.0 I.3MSO 16.0 12 0 14

51 I .1 Prnnlulbk SIImrS t n a I. CotIn'de No. W N1Gndc OrCOlICnlirr -,.M2S M30 M3S M408IIdAbovc

I) (2) (3) 4) IS) (6)i) sO .IS 01 9 0.20 0.20 020ii) 0.2S 02 3 02.\ 023 0.23iii) OSO OJI OJI 0.31 03 2Iv) 0.7S 0.36 OJ7 0.37 O JIv) 1.00 0.40 0.41 0.42 0.42vi) US 0.44 0.4S 4S 046vii) SO 0.46 041 0.49 0.49viii) 1.75 0.49 O SO 0.S2 0 52ix) 2.00 OSI 0.S3 0.54 0.55x) 2.25 0.53 0.55 0.56 0.S7xi) 2.SO 0.5S 0.57 0.51 0.60

xii) 2.75 0.S6 s 0 .60 0.62xiii) 3.00 IIIll Oj7 0.60 0.62 0.63IbofcNOTE - A. is dill wca of \oa i1IadNi laISioa .ciDbCCIIiUIIwtIidI COIlliIM:s asc ClIIC dm::ti ICdllpdlbc) Oftd die being CIOIIIidc:ftd at:qlI 1IltlcR the full I l aI ofllcIIsioa rcinfoRancnI may be IlSCd provided the dcUifinalXllIIilnnIlIO lU.111ld l6.1.3atIS456.

I )

51No.

i)ii)iii)iv)v)vi)

NOlESI The values of permissible she. stress in oona ClC weliven inT-,*3 .1 The bond suess given ill col S shall be inaeascd by 2Sp acaJl fort n ill compression.3 In c:asc of deformed bm confunnina to IS 1716. lhc bondstresIc:S gival IIboe maybe inaaIsed by 60 pcrca1l

3

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IS 3370 Part 2 : 20095 FLOORS5.1 Provisionsof Movement JomtsMovementjoints shall beprovidedinaccordancewithIS 3310 Part .5.2 Floon ofTaoks RestiDg GroundThe floors of tanks resting on ground shall be inaccordancewith IS 3310 Part I .5.3 F100n of Taoks Resting on SupportsIf the tank is supported on walls or other similarsupports. the floor slab shall be designed for bendingmomentsdue towater loadand self weight.The worstconditionsof loadingmayno t be thosegivenin 22.4.1of IS 456, since water level extends over all spans innormal construction except in the case of multi-celltanks, thesewillhave to bedeterminedby the designerin each particular case.5.3.1 When the floor is rigidly connected to the wallsas is generally the case the bendingmoments at thejunction between the walls and floor shall be takeninto accounl in the design of floor togetherwith anydirect forces transferred to the floor from the walls orfromthe floor to the walldue to the suspensionof thefloor fromthe wall.6 WALLS6.1 Prorisi of Joints6.1.1 Sliding Joints M ase O M WallWhere it is desired to allow the walls to expand orcontract separately from the floor, or to preventmomentsat the base of the wallowing to fixity10 thefloor sliding joints may be employed.6.1.1.1Constructionsaffecting the spacing of verticalmovementjoints are discussed in IS 3310 Part I .While the majorityof thesejoints maybeof the partialor complete contraction type, sufficient joints of theexpansion type should be provided to satisfy therequirementsof is3310 Part I6.2 Pressure nWalls6.2.1In liquidretainingstructureswithfixed or floatingcovers,thegaspressuredevelopedaboveliquidsurfaceshall be added to the liquid pressure.6 U Whenthewallofliquid retainingstructureisbuiltin groundor has earth embanked against it. the effectof earth pressure shall be taken into account asdiscussed in IS 3370 Part I .6.3W ofTaoks Rectanplaror PoI) IOoaI in PlaoWhiledesigning thewallsof rectangularor polygonal

4

concrete tanks, the following points should be takencare of:

a In plane walls. the liquid pressure is resistedby both vert ical and horizontal bendingmoments. An estimate of the bendingmoments in the verticaland horizontal planesshould be made . The horizontal tensioncaused bythe direct pulldue towaterpressureonend wallsshould beadded to that resultingfrom horizontal bending moment.

b On liquid retaining faces, the tensile stressesdue to the combination of direct horizontaltension and bending action shall satisfy thefollowing condition:

where Te =calculated direct tensile stress in

concrete.Oet = permissibledirect tensilestress in

concrete seeTable IOeM =calculated tensile stress due tobending in concrete. andacbc =permissible tensile stress due tobending in concrete s Table I .

c At the vertical edges where the walls of areservoir are rigidly joined, horizontalreinforcement and haunch bars should beprovided to resist the horizontal bendingmoments. even if the walls arc designed towithstand the whole load as vertical beamsor cantilever without lateral supports.

In the case of rectangular or polygonal tanks, the sidewalls act as two way slabs. whereby the wall iscontinuedorrestrainedin the horizontaldirection. fixedor hinged at the bottom and hinged or free at the top.The walls thus act as thin plates subject to triangularloadingandwithboundaryconditions varyingbetweenfull restraint and free edge. The analysis of momentand forcesmaybe madeon the basis of any recognizedmethod. However. moment coefficients, forboundaryconditions of wall panels for some common cases arcgiven in IS 3370 Part 4 for general guidance.6.4 Walls of Cylindrical TanksWhile designing walls of cylindrical tanks, thefollowing points should be borne in mind:

a) Walls of cylindrical tanks are either castmonolithically with the base or are set ingrooves and keyways movement joints . Ineither case deformation of the wall under the

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influence of liquid pressure is restricted at thebase .

b Unle ss the extent of fixity at the base isestablished by anal sis with due considerationto the dimensions of the base slab. the type ofjoint between the wall and slab and the type:of soil supporting the base slab. it is advisableto assume wall to be fully fixed at the base.

Coefficient for ring tension and vertical moments fordifferent conditions of the wal ls for some commoncases are given in IS 3 37 0 P art 4 for generalguidance.7 ROOFS7.1 Provision of Movement JointsTo avo id the possibility of sympathetic cracking. it isimportant to ensure that movement joints in the roofcorrespond with those in walls if roof and walls aremonolithic. If however. provision is made by meansof a sliding joint for movement between the roof andthe wall correspondence of joints is not important 7.2 Water-TightnessIn case of tanks intended for the storage of water fordrinking purposes the roof must be made water-tight.This may be achieved by limiting the stresses as for

IS 3310 Pan 2 : 2009the rest of the tank or by use of the covering ofwaterproof membrane or by providing slopes to ensureadequate drainage.8 O E T A I L I ~8.1 Minimum Reinforcement8.1.1 The minimum reinforcement in walls. floors androofs in each of two directions at right angles. withineach surface zone shall not be less than 0.:\5 percentof the surface zone cross section as shown in Fig . Iand Fig. 2 for high strength deformed bars and notless than 0.64 percent for mild steel reinforcement bars.The minimum reinforcement can be further reducedto 0.24 percent for deformed bars and 0.40 percent forplain round bars for t a n h having any dimension nOlmore than 15 m. In wall slabs less than 200 mrn inthickness. the calculated amount of reinforcement mayall be placed in one face . For ground slabs less thanl rnm thick uFig . 2 the calculated reinforcementshould be placed in one face as near as possible theupper surface consistent with the nominal cover. Barspacing should generally not exceed :\00 OlIO or thethickness of [he section. whichever IS less .8.2 Size of Ban, Distance BetwHn Ban. Laps an dBends - Size of bars . distance between bars. lap > andbends in bars. and fixing o r h a n shall be in accordancewith IS 456 .

NOTE - For < 500 mm assc.me ead l rW dolament lace controls n deptI l0100I lCt8tlI.For . 500 mm assume each reinforcement face controls S mm depth 01concreteignoring any central core beyoncllhis sUl1ace dep1h.

FIG . I SURFACE ZoNES: WAUS AND SUSPNDED SL as

5

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IS 3370 Part 2) : 2009 ~ ~ lUNDER3 mm NO BOTTOM_ __ R INFOR M NT

~ on300mc; TO ~ ~ 1L _ : : : : t1 mmfo

OVER5 mmL 1 . / 77 rr77 7 /77 r 77 r/ . 7 7 7

FIG . 2 SURFACE ZoN S : GROUNDED SLABS

ANNEXA oreword, and Clause4.4.3

CRACK WIDTH DUE TO TEMPERATURE AND MOISTUREA I CALCULATION OF MINIMUM REIN Grade of M25 M30 M35 M40 M45 M50FORCEMENT CRACK SPACING AND CRACK concreteWIDTHS IN RELATION TO TEMPERATURE fa N mm2 5 1.3 1.45 1.6 I.7 1.8AND MOISTURE EFFECTS IN THIN SECTION f y = characteristic strength of the reinforcement.A I.I The design procedures given in A I.2 to A I.3are appropriate to long continuous wall or floor slabsof thin cross section. A-2 considers thick sections.A I.2 Minimum ReinforcementTo be effective in distributing cracking. the amount ofreinforcement provided needs to be at least as great asthat given by the formula;

Peri = critical steel ratio, that is, theminimum ratio,of steel area to the gross area of the wholeconcrete section , required to distribute thecracking;h = d irect ten sile stren gth of the immatureconcrete, which is taken as given below:

where_fa

Pcr i l f .. . 1)

6

For ground slabs under 200 mm thick the minimumreinforcement may be assessed on the basis ofthickness of 1 mm and placed wholly in the topsurface with cover not exceeding 50 mm. The tops ur fa ce zone for ground slab from 2 to 5 mmth ick may be asses sed on half the thickness of theslab. For ground slabs over 5 mm thick, considerthem as thick sections with the bottom surface zoneonly 1 mm thick.A I.3 Cracks can be controlled by choosing thespacing of movement joint and the amount ofreinforcement. The three main options are summarizedin Table 2 of IS 3370 Part I) .A-l .4 Crack SpacingWhen sufficient reinforcement is provided to distributecracking the likely maximum spacing of crack S ushall be given by the formula:

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IS 3370 Part2) : 2009

For immature concrete, the value of may be takenas unity for plain round bars and 213 for deformed bars.The above formula may be expressed for designpurposes as:

wheref . = ratio of the tensile strength of the concreteJ fc, 10 the average bond strength betweenconcrete and steel, = size of each rein forc ing bar, andp = steel ratio based on the gross concrete

section.

cc = coefficient of thermal expansion of maturecon crete, and

TI = fall in temperature between the hydrationpeak and ambient.Th e valu e of T1 depends on the temperature ofconcreting, cement content, thickness of the memberand material fo r shu tte rs. As guide line, it isrecommended to use T = 30 for concreting insummer and 20 for concreting during winter, whenstee l shutters are used . For other conditions, the valueof may be appropriately increased.In addition to the temperature fall TI , there can be afurther fall in temperature, T2due to seasonal variations.The consequentthermal contractionsoccur in the matureconcrete for which the factors controlling crackingbehaviour are substantially modified. The ratio of thetensile strength of concrete to bond strength, isappreciably lower for mature concrete. In add ition, therestraint along the baseof the member tends to be muchmore uniform and less susceptible to stress raisers , sincea considerable shear resistance can be developed alongthe entire length of the construction joint.Although precise data arenot available for these effectsa reasonable est imate may be assumed that thecombined effect of these factors is to reduce theestimated contraction by half. Hence the value ofwwhen taking an additional seasonal temperature faninto account is given by:

A-I THICK SEcrIONS

where

W u. = x ~ x r +7;) ... (6)2When movement joints are provided at not more than15m centres, the subsequent temperature fall, T neednot be considered.

For thick sections, major causes of cracking are thedifferences which develop between the surface zonesand the core of the section. The thickness of concretewhich can be considered to be within the surface zoneis somewhat arbitrary. However, site observations haveindicated that the zone thicknesses for > 500 mm inFig . I and Fig. 2 are appropriate for thick sections,and the procedure for calculating thermal crack controlreinforcement in thick sections is same as that for thinsections.The maximum temperature rise due to heat of hydrationto be consideredshouldbe the average value for the entirewidth of section . The temperature rise to be consideredfor the core should be at least Iwehigher than the valuewhich would be assumed for the entire section.

. ..(3)

.. . (2 )

(4)

. . . (5)

WMu =s u e

x ~ XwMas = 2 I

wherenb =b = =

where

number of bars in width of section,width of section ;overall dep th of member, and

SMu= obtained from WMu The width of a fully developed crack due to dry ingshrinkage and heat ofhydration contraction in lightlyreinforced restrained walls and slabs may be obtainedfrom:

e = fEa + r - (100 x 1(t6)]wMu = estimated maximum crack width,sMu = estimated likely maximum crack spacing,e = estimated shrinkage strain, andtic = estimated total thermal contraction after

peak temperature due to heat of hydration.For immature concrete the effective coefficient ofthermal contraction may be taken as one half of thevalue for mature concrete dueto the high creep strainin immature concrete). .For walls exposed to normal climatic conditions theshrinkage strain less the associa ted creep strain isgenerally less than the ultimate concrete tensile strainof about 100 x t(f6 unless high shrinkage aggregatesare used. Hence the value of WMu for cooling toambient from the p k hydration temperature may beassumed to be:

7

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IS 3370 Part2) : 2009ANNEXB

(Foreword, and Clause 4.4.3)CRACK WIDTIIS IN MATURE CONCRETE

For a limiting design surface crack width of 0.1 mm:

b,(D-.1 )(a -x)z = 3E.A,(d-.1 )

B.1 ASSESSMENT O F CRACK WIDTHS INFLEXUREProvided that the strain in the tension reinforcement islimited to 0.8 fiE, and the stress in the o n r t ~ islimited to 0.45 lc the design surface crack Widthshould not exceed theappropriate value given in4.4.1.2and may be calculated from equation 7 : 1=

b(D - .1 ) 0 x3E,A,(d-x)

... 8)

.. . 9

B-2 AVERAGE STRAIN IN FLEXURE

wherew =design surface crack width.Dc> =distance from the point considered to the

surface of the nearest longitudinal bar,., = aw:rage strain at the level where the cracking

is being considered. To be calculated inaccordance with 8-1.

C....=minimum cover to the tension steel,D = overall depth of the members, and.l =depth of neutral axis.

where

1 =b, =D =.r =E. =A, =d =d =

30,, ..2(0 ....1+ - - D-.1 . .. (7) strain at the level considered.strain due to the stiffening effect of concretebetween cracks.

width of section at the centroid of the tensionsteel,overall depth of the member.depth of the neutral axis,modulus of elasticity of reinforcement,areaof tension reinforcement,effective depth, anddistance from the compression face to thepoint at which the crack width is beingcalculated.

The average strain at the level where cracking is beingconsidered . is assessed by calculating the apparentstrain using characteristic loads and normal clasticlheory .Where flexure ispredominanl hut some tensionexists at the section. the depth of the neutral axis shouldbe adjusted. Thecalculated apparent strain, , is thenadjusacd to take into acccunt the stiffening effect ofthe concrete between cracks z . Th e value of thestiffening effect may be assessed from B3, and

,. = , - 6iwhere

. = IVCfale strain It the level where cracking isbeing considered,

, = strain at the level considered, and6i = strain due to stiffening effect of concrete

between cracks.B-3 STIFFENING EFFECT OF CONCRETE INFLEXUREThe stiffening effect of the concrete may be assessedby deducting from the apparent strain a value obtainedfrom equations (8) or (9) .For a limiting design surface crack width of 0.2 mm:

8

B- 4 ASSESSMENT OF C RA CK W ID TH S INDIRECT TENSIONProvided that the strain in the reinforcement is limitedto 0.8fiE,. the design crack width should not exceedthe appropriate value given in 8 of IS 3370 (Part Iand may be calculated from equation 10) :

w=3a tl . .. 10where C. is assessed in accordance with U.S.

U.SAVERAGE STRAIN IN DIRECT TENSIONTh e average st ra in is assessed by calculating theapparent strain using characteristic loads and normalelastic theory. The calculated apparent strain is thenadjusted to take into account the stiffening effect ofthe concrete between cracks. The value of the stiffeningeffect may be assessed from 8- .B-6 STIFFENING EFFECT OF CONCRETE INDIRECT TENSIONThe stiffening effect of the concrete may be assessedbydeducting from the apparent strain a value obtainedfrom equation II or ( 12) .For a limiting design surface crack width of 0.2 mm:

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IS 3370(Part Z) : ZOOb = width of the: section at the centroid of the

tension steel,IJ = overall depth of the member.E = modulus of elasticJly of reinforcement, andA, = area of tension reinforcement.

The stiffening effect (acton should not be interpolatedor extrapolated and apply only for the: crack widthsstated.

. . . (11)

.. . (12)b Dt1 = A~ = strain due to stiffening effect,

2b Dt1 = 3 AFor a limiting design surface crack width of 0.1 mm:

ANNEXCForeword

COMMITTEE COMPOSmONCement and Concrete Sectional Committee, CEO 2

rraN1D1ioftDelhiTourismand Transportation ~ l o p l D a l l CArponrionLtd.NewDdhiACC Ltd. MumbaiAtomic Energy Relul.tory Board. Mumbai

Building Material. and Tc:c:hnoloi) Promotion Couecil,New DelhiCement Corporation of India Limited. New DelhiCement Manuf....1W c:n A-..:iaIiuo. NoidaCentral Board of Irriplioa and Powcc. New DcIbiCentral Building Research Institute: (CSIR). RoorkCentral Public: Work. Dcpu1mcnt. New DelhiCentral Road RCIC&Idl lnslil1llC (CSIR). New DelhiCentral Soil and MaIcriaI. Rcseardl Station. New DelhiCentral W.ler Commission. New Dc:lhiConmat TcclmoloJie. Pvt l id. Kolk.t.Constntc:tion Industry Development Council. New Delhi

Dc:lhi Dc:velopmcm Authority. New DelhiDircetoru: Genc:nI of Supplica ;Disposals. New Dc:lbiEn&inccn IndiaUmilCd. New DelhiAy Ash Unit,Dcpu1mc:nl of Science ;TcdlnoloaY.

Ministryof Scic:nce ;Tc:chnoIoJy. New Delhi

R ~ m u a t i ~ lStuta Jmf. KuaAH C ~SItRI NAYIla< eP. SalNlvASAH A I U ~ ,DR Pa_a C. B,ulJ

SHII L R. 8.-. (AW ,)SHI1 J. K. ...... SHII C. N. JM' A I t , ~ ,SKII R. R ~ C l E

SHIu M. K. Ao.\awAi l A / , , ~ ,SH . E. N. Mu-11f

Da S. P. OItoallA/ ,)MDlIIEI l SEaa....

(Ovu.) (AI , , , )0.. B. K. RAIlDa S. K. G aW l A/,, ,,*)Oau EMx_ (DI:sx

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IS 3370 Part Z) : 2009rrUlt i :UIIU II

Gammon India Limlled . M u ~GnIim ~ LimilEd. Mumbai

HOUIillJ IIId Urllan Development CorponIIion Umired.Sew Dd i

Indian Bveau of Mines, NAfllUI

IDdi.Ia Jnstjl1llC of TcchaolocY . Roortce

Iadiaa RC*Is CongJas. New DelhiJllltil1llC fe. ResearclI. Developmenl It Trainm, of

COIISlI'IICIioa TI1Idc.. 1JIIti11llC fe. Solid WMac RClCal Ch &; EcoiOlicaJ Balance.

VisakhapImamM8dr.- e ta Lad, 0IcMaiMiJiwy Scnica. EapDecria Cbiers BI lIDCh,

AzfII'J . . . . . . .1EiS, New DdhiMIlIislry of R _ T...-port A HipwaY . Nao DelhiNMMIaaI e i I for < : 1 . . t BlIiIdlllJ MaIuiaIs,BaIIaIII-flN lac Houc. Kol.bla

OCt. IIIlIia UaUred. New Delhihblic WOIb D L p a l Gowcnunca of MlIIIIbM~ I i c ; WuRs 0epw1me.. . GcnemlllCat of Tarail N8du.. Oteanai Oaip ol sc a.rdI Orpnizalioa (Minillry of Railways).l A d : _Sanpai laduslrlea Limilrd. S an p Nap . Ranp Reddy Disrricl

10

r r ~ . f m t a l i ~SHal S. A . RUlUI

SHIll V. N. HEGGAllE A I I ~ , . , . a r ~ )SHill A. K. JAIN

SHRI M. C. AGIlA:ro Al A l t ~ , . , . a l ~ )SHill C. M . DoIlDtSHill B. K. JAGT\A A l t u n a l ~CHAoIllMAN AND MANAGING DtItCTOR

SHRI V ARIIL KUM R A l t ~ m a l ~SIlIU S. S. OM

SHIU MEI: Rl1l H..sAN Alttmau)SHaI L N. Am;

SHa1 D. SIllNIVASAH A l l ~ r n a l t-oF V. K. GunAOIl BIM INDF. SINGH A l l t m a t ~SIDEI'AIIY GENew.

DIaJ;croK Allernate)OIlN. RAGIlAVf.NllaAoOIl N. B I:ANUMATlllDAS

_N. K.u.JrMs (AIIU71l/1t)SHaIV. JALiANAT1WI

SHRI BAUJI K. MOOCTHY (Alremare)Slw J. B. SitAaNA

Sua YOOI SK Saow. (AlrenttJU)S..u A. N. DltooAPt.Aa

S S. K. PulU lAl1enttJU)SHRI R. C. W

Da M. M. Au A l t e m a r ~ )SHRI B. R. MWIAo

_nS. A. KAusml (Alrel'1ll/lt)Slllu U. S. P. Vf. MAo

SMa AJMNll SHRIVATIlYA ( A I , ~ I 7 I t I I l )OIl S. C. AHLuwAuA . \ T I V l lSUPIIIImMlDlO ENoiNmt (DEsKiN)

ExIlC\1TM A 1 l t m a l ~ )SHRI R. M. SH o.....SMa V K. YAllAYA Alk/lltlll )

SHRI D. B. N. R OOIl H. K. PIITlWIt Allt/lltlll )OaF fMcDe a N A ~ DAM) I lGNEEa Alul 7llZk)SHIt, A. C tEu.APrluI

S J . ~ W I l _s . r S ~

S R ~ ~s.. P.D. ICaLo\I S. J. Sawt AlunlQll )

OIl H. C. VISVESY il Y8IIuta s.o. (AIIl /lIaIe)s.r SuuKro e n un

S 8 swMT DHAa A l k ~

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OrgUltil ll lO VolunW)' Organ iution in (nteresl of CQlUUmer Ed.la iOll,

New DelhiBIS Directorate General

IS 3370 (Part 2) :R ~ p s n r J w ( I )

Slcll HUONfT Kl '.....

SMaA. K. SAlHl . Scielltill F' t Head a ~ Eng[ I l ~ u l l Diftdot Gmt:nI ( E J ~ o . ? l l

M ~ ~ , ~ ? I a r iS.. ., SANJn PANTScicntill ' E' .Direclor Enul . BIS

SHR I S . AIllIN K l .. . . ..Scjenris; 'B' (Civ En I . BIS

Concrete Subcommittee. CEO 2 : 2Delhi Tourism .Transportation Developmcnl Curporation

LId. NewDelhiACC Ltd. MumbaiAlOmic EnergyRcgularoryBoard, MumbaiBuildin MaIeriaIs andTedInoloc PromotionCouncil.New DelhiCenlrll Building Research Institute (CSIR). RoortceCenlrll Public WOIb Deputmcnl. New DelhiCcnuaJ Rl* Resean:h Inllitute ('SIR). Ne A' DelhiCenlrll Soil .Materials Resean:h Sl.IlIon. New DelhiCcnlnl Waler Commission . New Delh i

Engincen India Limited. New DelhiA)' Ash Uttil, Dep.tmmt of Science Md TcchnoloJY.

Minislry of Science lCdInoIOC. New DelhiGammoa India Limitlod. Mumbai

Grasim Industries LId. MtunbaiGujarlllAmbaja CementLimited, Ahmedabed

Indian InstitulI: of TedlnolO )'. KanpurIndian Instit1Ite of TecbnoloV. RoorteeLanen IIld Toubro Limitrd.,ChcanaiMilitar)' Engineer Eogineerin-Cbier. Branch.

Army Hcadqunm . NewDelhi

ANIL BANClMlll P. B ~ A Y A l k _

OIl Pa.-. C. Buu L. I t 8- .J l ( A 1 u _ )

J. K. I'LuAo pAlCAJ 0\wrA A ~

OIl B. K. RADOIl S. K. Aa.uIw.L AIu_S ~ E . . - o - . .

ExIlCVl1VZ e . . ~ ~O I l ~ M A ~ (A, . )

SJe. MI-.uD RATMAMS.. N. ClwolIlAJQQI.IMI A I _ I

D1aIIl TlJl C -.MDDI0Durt DlIInoI eaMDD l AW - I

S_ Ar vvoo KlIMA.s... T. BAIAAI

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IS 3370 Part 2) : 2009OrganillJli )fI

Ministry of Road Transport and Highways. New Delhi

National Buildings Construction Corporation Limited.New Delhi

National Council for Cement Building Materials.Ballabgarh

National Institute of Technology. Warangal

Nuclear Power Corporation of India Limited, Mumbai

Pidilite lnduslries Limited, MumbaiReady Mixed Concrete Manufacturers' Association. BangaloreResearch, Design :Standards Organization (Ministry of Railways),

LucknowStructural Engineering Research Centre (CSIR). CbennaiTandon Consultants Private Limited, New DelhiTCE Consulting Engineers Limited. Mumbai

Torsteel Research Foundation in India, New Delhi

In personal capacity (35. ari AvenI e nnammaNaid:er t ~ e t KJutiamuthllr, C o i m b a t o ~

In personal capacity (36. Old Mh Nagar, Wardha Raad.Nagpl/r)

Representativeis}SHRI T. B. BANERlf

SHRl KAMISH KUM AR (A/lemale)SHRI L. P. SINGH

SHRI DARSHAN SINGH (A/lema e )S R R. C. WASON

SHRI H. K. JULKA A//emale)DR C. B. KAMESwARA RAO

OR D . RAMA SESHU A/temalt)SHRl U. S. P. VERMA

SHRl ARvlND SHRIVATAVA Alltmale)SHRI P. L. PATRY

SIlIlI K. PADMAKAR Alltmate)SHRI VUAYKUMAR R. KULKARNIJOIKT DnlEcroR STANI>AIlDS (B :S)/CB-IJoorr DtIlECTOll STANa RDS (B S)/CB- 1 Alternate)SHRI T. S. KRISHNAMOORTHY

SHRI K. Bf\LMUBRAMANlAN Alternate)SHRI MAHESH TANOON

SHRI VINAY GuPTA A/temate)SHRI J. P. H RAN

SHRI S. M. PAlEK R Altemate)DR P. C. CHOWDHURY

DR C. S. V L ~ H W A N A T H A Altemate)DR C . RAlKUMAR

SHRI Lurr KUWAR JAIN

Panel for Revision errs 3370 (Parts 1 and 2). CED 2 : 2JPINational Council for Cement and Building Material.

BaIlabgazhIn persoaaI capacity (36. Old Mh Nagar, Wardha Rood.

Nagpl/r)Central Road Researm Institule (CSlR). New DelhiDelhi Tourism and TransportAtion Development Corpontion

Ltd, NewDelhiGammon India Ltd, MumbaiIndian Institute of Technology, New Delhi

lndia:1 Institute of Technology, RoorkeeMilitary Engineer Services. Engineer-in-Chiefs Branch.

Anny Headquarters,NewDelhiNalioaal Council for Cement andBuilding Material.

BaIIabgarhScbool of Planning aDd Architecture. New DelhiStnx:tDJa1 Engineering Resarch Centre (CSIR). OlcnnaiTCE Consulting Engineers Limited, Mumbai

In personal capacity K-U2. Kavi NalIar, GhcWabat )

12

ORANn KUMAR CoMerur b e f o ~ 18 October 20 6)SHRI LALIT KUMAR JAIN CODetlU since /8 October 20 6)DIRf.CTOtl

SHRI SATANDfJl KlJMAIl

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