15 3370 (Part 2) : 2009
~ ~ ~~gol .~ ~ ~ ~i\!ir~r~ _ ~ ~
1fl1T 2 MCi4~d QJs6le ~i(q~~
Indian Standard
CONCRETE STRUCTURES FOR STORAGE OF
LIQUIDS - CODE OF PRACTICE
PART 2 REINFORCED CONCRETE STRUCTURES
( First Revision)
ICS 23.020.01; 91.080.40
© BIS 2009
BUREAU OF INDIAN STANDARDS
MANAK SHAVAN . 9 BAHAD tJR SHAH ZAFAR MARG
NEW DELHI 110002
June 200'J
PriaGroup6
Cement and Concrete Sectional Committee, CED 2
FOREWORD
This Indian Standard (Part 2) (First Revision) was adopted by the Bureau of Indian Standards. after the draft
finalized by the Cement and Concrete Sectional Committee had been approved by the Civil Engineering Division
Council.
This standard was first published in 1965. The present revision has been taken up with a view to keeping abreast
with the rapid development in the field of construction technology and concrete design and also to bring further
modifications in the light of experience gained while applying the earlier version of this standard and theamendment
issued .
The design and construction methods in reinforced concrete and prestressed concrete structures for the storage
of liquids are influenced by the prevailing construction practices, the physical properties of the materials and the
climatic condition. To lay down uniform requirements of structures for the storage of liquids giving due
consideration to the above mentioned factors, this standard has been published in four parts, the other parts in the
series 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 structures
of special forms or in unusual circumstances, special literature may be referred to or in such cases special systems
of design and construction may be permitted on production of satisfactory evidence regarding their adequacy
and 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 or
prestressed concrete is entrusted to a qualified engineer and that the execution of the work is carried out under the
direction of a qualified and experienced supervisor.
All requirements of IS 456 : 2000 'Code of practice for plain and reinforced concrete (fourth revision)' and
IS 1343 : 1980 'Code of practice for prestressed concrete (first revision)', in so far as they apply, shall be deemed
to form part of this standard except where otherwise laid down in this standard. For a good design and construction
of structure, use of dense concrete, adequate concrete cover, good detailing practices, control of cracking, good
quality assurance measures in line with IS 456 and good construction practices particularly in relation to
construction 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 and
damp-proofing of basements;
b)
A new sub-clause on loads has been added under the clause 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; and
d} Provision for crack width calculations due to temperature and moisture and crack 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, expressing the results of a test or analysis, shall be rounded off in accordance with
IS 2 : 1960 'Rules for rounding off numerical values (revised)' . The number of significant places retained in the
rounded off value should be the same as that of the specified value in this standard.
IS 3310 (Part 2) : 2009
Indian Standard
CONCRETE STRUCTURES FOR STORAGE OF
LIQUIDS - CODE OF PRACTICE
PART2 REINFORCED CONCRETE STRUCTURES
( First Revision )
1 SCOPE
3 GENERAL REQUIREMENTS
1.1 This standard (Part 2) lays down the requirements
applicablespecificallyto reinforcedconcrete structures
for the storage of liquids, mainly water. These
requirements are in additionto the generalrequirements
laid down in IS 3370 (Pan 1).
Design and construction of reinforced concrete liquid
retainingstructures shallcomply withthe requirements
of IS 3370 (Part I) and IS 456 unless otherwise laid
down in this standard.
1.2 This standard does not cover the requirements for
reinforced and prestressed concrete structures for
storage of hot liquids and liquids oflow viscosity and
high penetrating power like petrol. diesel oil. etc. This
standard also does not cover dams, pipes. pipelines.
lined structures and damp-proofing of basements.
Special problems of shrinkage arising in the storage
of non-aqueous liquid and the measures necessary
where chemical attack is possible are also not dealt
with. The recommendations. however. may generally
be applicable to the storage at normal temperatures of
aqueous liquids and solutions which have no
detrimental action on COncrete and steel or where
sufficient precautions are taken to ensure protection
of concrete and steel from damage due to ,action of
such liquids as in the case of sewage.
2 REFERENCES
The following standards contain provisions, which
through reference in this text. constitute provisions of
this standard. At the time of publication. the editions
indicated were valid. All standards are subject to
revision and parties to agreements based on this
standard are encouraged to investigate the possibility
of applying the most recent editions of the standards
indicated below:
/SNo.
456: 2000
1786 : 2008
TItle
Code of practice for plain and
reinforced concrete (fourth revision)
Specification for high strength bars
and wires for concrete reinforcement
(fourth revision)
3370
Concrete structures for the storageof
liquids - Code of practice:
(Part 1) : 2009 General requirements (first revision)
(Part 4) :·1967 Design tables
4 DESIGN
4.1 General
Provisionsshall be made for conditions of stresses that
mayoccur in accordance with principlesof mechanics.
recognized methods of design and sound engineering
practice.In particular. adequate consideration shall be
given to the effects of monolithic construction in the
assessment of axial force. bending moment and shear.
4.2 Loads
Allstructures required toretainliquids shouldbedesigned
for both the full and empty conditions. and the
assumptions regarding thearrangements of loading should
be such as to cause the most critical effects. For load
combinations, waterload shall be treatedas 'dead 10a'1'.
Liquid loads should allow for the actual density of the
contained liquid and possible transient conditions. for
example. suspended or deposited silt or grit where
appropriate. For ultimate limit state conditions and
working stress design, liquid levels should be taken to
the maximumlevelthe liquidcan rise assumingthat the
liquid outletsare blocked. For serviceability. limit state
conditions, the liquidlevelshould be takento theworking
top liquid level or the overflow level as appropriate to
workingconditions. Allowanceshould be made for the
effects of any adverse soil pressures on the walls.
accordingto the compactionand/orsurchargeof thesoil
and the condition of the structure during construction
and in service. No relief should be given for beneficial
soil pressure effects on the walls of containment
structures in the full condition. Loading effects due to
temperature occurs when thermal expansion of a roof
forces the walls of an empty structure into the
surrounding backfill causing passivesoil pressure. This
effectcanbereducedby providinga slidingjoint between
the top of the wall and under side of the roof which may
be either a temporary free sliding joint that is not cast
IS 3370 (Part 2) : 2009
into a fixed or pinned connection. or a permanently
slidingjoint of IbSC:SSed limiting friction. M.ove~~ of
a roofmayoccur also wherethereis substantial vanauon
in the temperature of the containedliquid. Wherea roof
is rigidly connected 10 a wall thismay leadto additional
loading in lhe wall that should be considered in the
design. Earth coveringon reservoirroof maybe taken as
dead load . but due account should be taken of
construction loads from plant and heaped earth which
may exceeo the intended design load.
Thejunctions between variousmembers(betweenwall
and floor) intended to be constructed as rigid should
bedesignedaccordingly and effect of continuityshould
be accounted in design and detailing of each member.
4.5.1 Basis of Design
a) At any cross-section plane section remains
plane after bending.
b) Both steel andconcreteare perfectly elastic and
the modularratio has the valuegiven in IS456.
c) In calculationof stresses. for both flexural and
direct tension (or combination of both)
relating to resistance to cracking. the whole
section of concrete including the cover
together with the reinforcement can be taken
into account provided the tensile stress in
concrete is limited to Table I .
d) In strength calculations the concrete has no
tensile strength.
in 4.4 and 4.5 for design of water retaining structures
shan be followed:
Additionalprovisionsfordesign of floors.walls and
roofs are given in 5. 6 and 7 respectively. Structural
dements that are not exposed to the liquids or to
moist conditions shall be designed in accordance
with IS 456.
..... Umit State Desip
"'''.1 Limit State Req",irtmtllts
AllrelevantlimitStaleS shall be considered in thedesign
to ensurean adequate degree of safetyand serviceability.
...5.2 Permissible Stresseson Concrete
4.5.2.1 Resistance to cracking
Limit stlUe ofcollaps«
For calculations relating to the resistance to cracking.
the permissible concrete stresses shall conform to the
values specified in Table I . Altbough cracks may
develop in practice. compliance with assumption given
in 4.5.1(c) ensures that these cracks are not excessive.
The recommendations given in IS 456 shan be
followed.
...... 1.1 Limitstales ofserviceability
b)
4.5 Working Stress Design
Calculation of stresses shall be based on the following
assumptions:
One of lhe two alternative melhods of design given
a)
4.4.3.1 Crackwidthsforreinforced concretemembersin
direct tension and flexural tensionmay he deemed to be
satisfactory if steel S!reSS under service conditionsdoes
not exceed 115 N/mm2 for plain bars and 130 N/mm2
for high strength deformed bars.
The design of members shall be based on adequate
resistance to cracking and adequate strength .
4.3 Methods of Design
"1.1
that in mature concrete shall be calculated as given in
Annex B.
Deflection - The limits of deflection shaI1
be as per IS 456.
Croding - The maximumcalculalcd surface
width of cracks for direct tension and flex.ure
or restrained temperatureaod moisture effects
shall not exceed 0.2 mm with specified cover.
Table 1 Permissible Coacrete Stresses in
Calculations Relating to ResistaDce
to Cracking
(Chuues 4.5.I(c). 4.5.2.1 and 6.3(b)]
51
4.4.1.3 Partial safety factor»
Pcnaiulble COllUde Strata,
No.
NI
J
_-----A---_
The recommendationsgiven in IS 456 for partial safety
faet0r5for serv~ility shall be followed.
".4.1 Basis 01 Design
Design and detailing of reinforced concrete shall be as
specified in Section S of IS 456 except thal 37.1.1 of
IS 456 shall DOl apply.
4.OCrad~hs
i)
M2S
1.3
U
ii)
MJ()
1.5
2.0
iii)
jy)
y)
M3S
1.6
2.2
M40
1.1
2.4
M4S
2.0
2.6
yj)
MSO
NOTE - The
Crack widths due to the temperature and moisture
sUll be .1iY= in IS 4$6.
effects sha1J be calculated as given in Annex A and
2
2.1
YIIues of sbar JlrcsI in ~
2.1
IS 337. (Pari 2) : 1009
4.5.2.2 St~ngth calculation
steel shill be equal to the product of modular ratio of
steel and concrete, and the corresponding perm issible
tensile stress in concrete.
In strength calculations. the permissible concrete
stresses shall be in accoo:Iance wilb Table 2 and Table 3.
4.5.3.2 Strrngth calculations
'lable 2 Permissible Stres.Ws ia Coocftte
For strenglb calculations. the: perm issible stresses in
steel shall conform to the values specified in Table 4.
All values are in N/mm 2•
51
No.
C_pcuIioII
A
r
8cDding
(I)
i)
ii)
iii)
iv)
v)
vi)
r--....,
PftWillibk Straa Ie
Gradtof
CMCI"de
(2)
M25
M30
MJS
DiIUl
a.
a..
(3)
(4)
I .S
10.0
II .S
13.0
M40
'\
M4S
14.S
MSO
16.0
Strali. Iolld
(A ftf1IIe) lor
I'IahI Ban I.
TrtUIoe
T.bIe .. Pel misaible StreIRs ia Sled
Reinfonaneat for Streaeth
Sl
Na.
r..
(S)
0.9
1.0
1.1
6.0
1.0
9.0
14
I" .1-
(4)
liS
130
ill
to
12$
l.a
~1IId"III'CSS
,...,.
subjec:lecl
dim;lload
4.5.4 SI1~SStS Dw to Moisnlre or Tt"'IWtUttllY ClttJrtges
No separate cak:ulation is requin:d for stres.es due to
moisture or temperature change in the concrete
provided that:
Gndc OrCOlICnlir
r
HiP SIftIIIdl'
(3)
001_
Prnnlulbk SIImrStna I. CotIn'de ~
N1• •'
W
A.
I'IMI RAlUIld
(2)
ii) CompIasiYe
'lable 3 Pel ....ble Shear Stress ID Co9Crfle
(Claust 4.5 .2.2. and Tablt 2)
No.
r
i) TCIIIilc __ .. ..-bas
lIIIlb 0iftlCI IaIIian.
(I)
NOlES
I The values of permissible she. stress in oona'ClC we liven in
T-,*3.
1 The bond suess given ill col S shall be inaeascd by 2S
pacaJl for t.n ill compression.
3 In c:asc of deformed bm confunnina to IS 1716. lhc bond
stresIc:S gival IIbo¥e may be inaaIsed by 60 pcrca1l
51
RdIIf_t
MilclSlDdBm Dd:Jrnxld BIn
1.2
I.3
10.0
11.0
120
I'n1aIIIi1IIr srr-, ~ .
T~ ofSfna I. SCftI
a)
The reinforcement provided ~ nOl less than
Ibal specified in 8.
b)
M2S
M30
M3S
M408IId
Abovc
(6)
The recommendations of the standard with
regard to the provis ion of movement joinu
and for a suitable 51iding layer benealb the
tank. given in IS 3370 (Part I) arc complied
with.
-,.
(I)
(2)
(3)
(4)
IS)
i)
sO.IS
0.20
02.\
020
023
OJI
OJI
v)
1.00
0.41
0.31
0.37
0.42
vi)
US
I.SO
0.36
0.40
0.44
OJ7
0.4S
04S
0.46
041
0.49
0.23
032
OJI
0.42
046
0.49
c)
Iv)
0.2S
O.SO
0.7S
019
023
0.20
ii)
The tank. is to be lI)CCj only for the stora&e of
water or aqueous liquids It or near ambient
temperature and the concrete never dnes out,
and
1.75
2.00
2.25
0.49
O.SI
0.53
O.SO
0.S3
0.S2
0..52
0.55
0.S7
d)
2.SO
2.75
0.5S
0.57
Adequate precautions are taken to avoid
cracking of the concrete during the
coeseuetion period and until the lanle is put
into usc.
iii)
vii)
viii)
ix)
x)
xi)
xii)
0.S6
Oj7
0.55
O.s.
0.54
0.56
0.51
0 .60
0.60
0.62
0.60
0.62
0.63
Ibofc
NOTE - A. is dill wca of \oa&i1IadNi laISioa .ciDbCCIIiUII
wtIidI COIlliIM:s • asc ClIIC dm::ti'IC dllpdl bc)'Oftd die ~
being CIOIIIidc:ftd at:qlI • ~ 1IltlcR the full Il'aI of
llcIIsioa rcinfoRancnI may be IlSCd provided the dcUifina
lXllIIilnnIlIO lU.111ld l6.1.3 at IS 456.
xiii)
3.00 IIIll
".5.4.1 Shrinlease stresses may, however. be rcquin:d
to be calculated in special cases. when a shrinkage
coefficienl of 300 )( I()-6may be assumed.
... 5.... 2 Where reservoirs are protected with an
incemal impermeable lining. consideration should
be liven to the possibility of concrete eventually.
dry in, OUI. Unless it is establi5bc:d on the basis of
tests or experience Ibat the linin, has adequate crack
bridaing properties. allowance for the increased
effect of dryinl shrinka,e should be made in !he
design.
4.S.3 hrmissible Stresses in Stee!
4.5.3.1 Resistance 10 crac1illg
The tensile stress in the steel will necessarily be limited
by the requirement that the permissible !ensile Slres5
in thecoeerete is nOlexceeded; 50 !he tensile suess in
3
IS 3370 (Part 2) : 2009
concrete tanks, the following points should be taken
care of:
5 FLOORS
5.1 Provisions of Movement Jomts
In plane walls. the liquid pressure is resisted
by both vert ical and horizontal bending
moments. An estimate of the bend ing
moments in the vertical and horizontal planes
should be made . The horizontal tension
caused by the direct pull due to water pressure
on end wallsshould be added to that resulting
from horizontal bending moment.
b) On liquid retaining faces, the tensile stresses
due to the combination of direct horizontal
tension and bending action shall satisfy the
following condition:
a)
Movementjoints shall be provided in accordancewith
IS 3310 (Part I).
5.2 Floon ofTaoks RestiDg 00 Ground
The floors of tanks resting on ground shall be in
accordance with IS 3310 (Part I).
5.3 F100n of Taoks Resting on Supports
If the tank is supported on walls or other similar
supports. the floor slab shall be designed for bending
momentsdue to water load and self weight. The worst
conditions of loading may not be thosegivenin 22.4.1
of IS 456, since water level extends over all spans in
normal construction except in the case of multi-cell
tanks, these will have to be determinedby the designer
in each particular case.
where
5.3.1 When the floor is rigidly connected to the walls
(as is generally the case) the bending moments at the
junction between the walls and floor shall be taken
into accounl in the design of floor together with any
direct forces transferred to the floor from the walls or
from the floor to the wall due to the suspension of the
floor from the wall.
CTe(
=calculated direct tensile stress in
Oet
concrete.
= permissible direct tensile stress in
concrete (see Table I).
OeM'
=calculated tensile stress due to
bending in concrete. and
acbc = permissible tensile stress due to
bending in concrete (see Table I).
6 WALLS
c)
6.1 ProrisiOD of Joints
6.1.1 Sliding Joints al 1M Base O/IM Wall
Where it is desired to allow the walls to expand or
contract separately from the floor, or to prevent
moments at the base of the wallowing to fixity 10 the
floor. sliding joints may be employed.
At the vertical edges where the walls of a
reservoir are rigidly joined, horizontal
reinforcement and haunch bars should be
provided to resist the horizontal bending
moments. even if the walls arc designed to
withstand the whole load as vertical beams
or cantilever without lateral supports.
In the case of rectangular or polygonal tanks, the side
walls act as two way slabs. whereby the wall is
continued or restrainedin the horizontaldirection. fixed
or hinged at the bottom and hinged or free at the top.
The walls thus act as thin plates subject to triangular
loading and with boundary conditions varyingbetween
full restraint and free edge. The analysis of moment
and forces may be made on the basis of any recognized
method. However. moment coefficients, for boundary
conditions of wall panels for some common cases arc
given in IS 3370 (Part 4) for general guidance.
6.1.1.1 Constructions affecting the spacing of vertical
movement joints are discussed in IS 3310 (Part I) .
While the majorityof thesejoints may be of the partial
or complete contraction type, sufficient joints of the
expansion type should be provided to satisfy the
requirements of is 3310 (Part I).
6.2 Pressure On Walls
6.2.1 In liquidretainingstructures withfixed or floating
covers,the gas pressuredevelopedabove liquidsurface
shall be added to the liquid pressure.
6.4 Walls of Cylindrical Tanks
6.U When thewall ofliquid retainingstructureis built
in ground or has earth embanked against it. the effect
of earth pressure shall be taken into account as
discussed in IS 3370 (Part I).
While designing walls of cylindrical tanks, the
following points should be borne in mind:
a)
6.3 W" ofTaoks Rectanplar or PoI)'IOoaI in Plao
Whiledesigning the walls of rectangular or polygonal
4
Walls of cylindrical tanks are either cast
monolith ically with the base or are set in
grooves and keyways (movement joints). In
either case deformation of the wall under the
IS 3310 (Pan 2) : 2009
influence of liquid pressure is restricted at the
base .
b)
the rest of the tank or by use of the covering of
waterproof membrane or by providing slopes to ensure
adequate drainage .
Unle ss the extent of fixity at the base is
established by anal) sis with due consideration
to the dimensions of the base slab. the type of
joint between the wall and slab and the type:
of soil supporting the base slab. it is advisable
to assume wall to be fully fixed at the base.
8 OETAILI~(;
8.1 Minimum Reinforcement
8.1.1 The minimum reinforcement in walls. floors and
roofs in each of two directions at right angles. within
each surface zone shall not be less than 0.:\5 percent
of the surface zone, cross section as shown in Fig . I
and Fig. 2 for high strength deformed bars and not
less than 0 .64 percent for mild steel reinforcement bars .
The minimum reinforcement can be further reduced
to 0.24 percent for deformed bars and 0 .40 percent for
plain round bars for tanh having any dimension nOl
more than 15 m. In wall slabs less than 200 mrn in
thickness. the calculated amount of reinforcement may
all be placed in one face . For ground slabs less than
:lOO rnm thick (su Fig . 2) the calculated reinforcement
should be placed in one face as near as possible [0 the
upper surface consistent with the nominal cover. Bar
spacing should generally not exceed :\00 OlIO or the
thickness of [he section. whichever IS less .
Coefficient for ring tension and vertical moments for
different conditions of the walls for some common
cases are given in IS 3370 (Part 4) for general
guidance.
7 ROOFS
7.1 Provision of Movement Joints
To avo id the possibility of sympathetic cracking. it is
important to ensure that movement joints in the roof
correspond with those in walls if roof and walls are
monolithic. If, however. provision is made by means
of a sliding joint for movement between the roof and
the wall, correspondence of joints is not important ,
7.2 Water-Tightness
8.2 Size of Ban, Distance BetwHn Ban. Laps and
In case of tanks intended for the storage of water for
drinking purposes, the roof must be made water-tight.
This may be achieved by limiting the stresses as for
NOTE -
Bends - Size of bars . distance between bars. lap!> and
bends in bars. and fixing or han shall be in accordance
with IS 456 .
For D < 500 mm, assc.me ead'l rW'dolament lace controls en deptI'l0100I'lCt8tlI.
For D ,. 500 mm assume each reinforcement face controls 2SO mm depth 01concrete,
ignoring any central core beyoncllhis sUl1ace dep1h.
FIG . I SURFACE ZoNES: WAUS AND SUSP£NDED SLAas
5
IS 3370 (Part 2) : 2009
~
I~O~
o
---l
UNDER
300mm
_1__
NO BOTTOM
REINFORCEMENT
I
on
-~---r
I
300mc;., TO
__
~~
'L
1
_-:-:-::t
100mm
f
-I
o
OVER
500mm
L
1.-/"77 r r 7 7 7'/77" r/77" r/"".'7 7"//7
FIG . 2 SURFACE ZoNES : GROUNDED SLABS
ANNEXA
(Foreword, and Clause 4.4.3)
CRACK WIDTH DUE TO TEMPERATURE AND MOISTURE
A-I CALCULATION OF MINIMUM REINFORCEMENT CRACK SPACING AND CRACK
WIDTHS IN RELATION TO TEMPERATURE
AND MOISTURE EFFECTS IN THIN SECTION
fy
A-I.I The design procedures given in A-I.2 to A-I.3
are appropriate to long continuous wall or floor slabs
of thin cross section. A-2 considers thick sections.
For ground slabs under 200 mm thick the minimum
reinforcement may be assessed on the basis of
thickness of 100 mm and placed wholly in the top
surface with cover not exceeding 50 mm. The top
surface zone for ground slab from 200 to 500 mm
thick may be assessed on half the thickness of the
slab. For ground slabs over 500 mm thick, consider
them as 'thick' sections with the bottom surface zone
only 100 mm thick.
A-I.2 Minimum Reinforcement
To be effective in distributing cracking. the amount of
reinforcement provided needs to be at least as great as
that given by the formula;
_fa
Pcril-
f,
.. .(1)
A-I.3 Cracks can be controlled by choosing the
spacing of movement joint and the amount of
reinforcement. The three main options are summarized
in Table 2 of IS 3370 (Part I) .
where
Peri, = critical steel ratio, that is, the minimum ratio,
h,
Grade of M25 M30 M35 M40 M45 M50
concrete
fa' N/mm21.15 1.3 1.45 1.6 I.7 1.8
= characteristic strength of the reinforcement.
of steel area to the gross area of the whole
concrete section , required to distribute the
cracking;
= direct tensile strength of the immature
concrete, which is taken as given below:
A-l .4 Crack Spacing
When sufficient reinforcement is provided to distribute
cracking the likely maximum spacing of crack SMu
shall be given by the formula:
6
IS 3370 (Part 2) : 2009
where
.. . (2)
cc
TI
fc. = ratio of the ten sile strength of the concrete
J;,
p
= fall in temperature between the hydration
peak and ambient.
(fc,) 10 the average bond strength betwe en
concrete and stee l,
"
= coefficient of thermal expansion of mature
con crete, and
where
Th e valu e of T1 depends on the temperature of
concret ing , cem ent conte nt, thickness of the member
a nd material fo r shutters. As guideline, it is
recommended to use T, = 30 DC for concreting in
summer and 20 DC for concreting during winter, when
stee l shutters are used . For other conditions, the value
of T1 may be appropriately increa sed.
= size of eac h rein forc ing bar, and
= stee l ratio based on the gross concrete
section.
For immature concrete, the value of ;: may be taken
as unity for plain round bars and 213 for deformed bars.
In addition to the temperature fall TI , there can be a
further fall in temperature, T2 due to seasonal variations .
The consequent thermal contractions occur in the mature
concret e for which the fac tors controlling cracking
behaviour are substantially modified. The ratio of the
The above formula may be expressed for design
purposes as:
. ..(3)
tensile strength of concrete to bond strength,
where
= number of bars in width of section,
= width of section ;
D = overall dep th of member, and
appreciably lower for mature concrete. In add ition , the
restraint along the base of the member tends to be much
more uniform and less susceptible to stress raisers , since
a considerable shear resistance can be developed along
the entire length of the construction joint.
nb
b
SMu= obtained from WMu '
Although prec ise data are not available for these effects
a reasonable estimate may be assumed that the
combined effect of these factors is to reduce the
estimated contraction by half. Hence the value of w....
when taking an additional seasonal temperature fan
into account is given by :
The width of a fully developed crack due to drying
shrinkage and 'heat of hydration' contraction in lightlyreinforced restrained walls and slabs may be obtained
from:
WMu =s"'u
e
~, is
' " (4)
where
sMu = estimated likely maximum crack spacing,
W"'u. = S~ x~x(r. +7;)
... (6)
2
When movement joints are provided at not more than
15 m centres, the subsequent temperature fall, T2, need
e.. = estimated shrinkage strain, and
not be considered.
e
= fEa + Ere - (100 x 1(t6)]
wMu
= estimated maximum crack width,
tic
= estimated total thermal contraction after
A-I THICK SEcrIONS
peak temperature due to heat of hydration.
For 'thick' sections, major causes of cracking are the
differences which develop between the surface zones
and the core of the section. The thickness of concrete
wh ich can be considered to be within the ' surface zone '
is somewhat arbitrary. However, site observations have
indicated that the zone thicknesses for D > 500 mm in
Fig . I and Fig . 2 are appropriate for thick sections,
and the procedure for calculating thermal crack control
reinforcement in thick sections is same as that for thin
sections.
For immature concrete the effective coefficient of
thermal contraction may be taken as one half of the
value for mature concrete (due to the high creep strain
in immature concrete).
.
For walls exposed to normal climatic conditions the
shrinkage strain less the associated creep strain is
generally less than the ultimate concrete tensile strain
of about 100 x t(f6 unless high shrinkage aggregates
are used. Hence the value of WMu for cooling to
ambient from the peak hydration temperature may be
assumed to be:
wMas
= s~ x~XT.
2
I
The maximum temperature rise due to heat of hydration
to be considered should be the average value for the entire
width of section . The temperature rise to be considered
for the core should be at least I we higher than the value
which would be assumed for the entire section.
. .. (5)
7
IS 3370 (Part 2) : 2009
ANNEXB
(Foreword, and Clause 4.4.3)
CRACK WIDTIIS IN MATURE CONCRETE
B.1 ASSESSMENT OF CRACK WIDTHS IN
FLEXURE
b,(D-.1')(a'-x)
&z = 3E.A,(d-.1')
Provided that the strain in the tension reinforcement is
limited to 0.8 fiE, and the stress in the concret~ is
limited to 0.45 lcD- the design surface crack Width
should not exceed the appropriate value given in 4.4.1.2
and may be calculated from equation (7) :
... (8)
For a limiting design surface crack width of 0.1 mm :
&.1=
Ub, (D - .1')( 0'- x)
3E,A,(d-x)
.. . (9)
where
30,,£ ..
2(0" -C.... )
1+ - - - --
. .. (7)
&1
&.1 = strain due to the stiffening effect of concrete
between cracks.
D-.1'
where
b, = width of section at the centroid of the tension
steel,
= design surface crack width.
Dc> = distance from the point considered to the
w
D = overall depth of the member.
surface of the nearest longitudinal bar,
.r = depth of the neutral axis,
= aw:rage strain at the level where the cracking
&.,
E. = modulus of elasticity of reinforcement,
is being considered. To be calculated in
accordance with 8-1.
C....
= minimum cover to the tension steel,
D
= overall depth of the members, and
.l'
=depth of neutral axis.
A, = areaof tension reinforcement,
d = effective depth, and
d
= distance from the compression face to the
point at which the crack width is being
calculated.
B-2 AVERAGE STRAIN IN FLEXURE
B-4 ASSESSMENT OF CRACK WIDTHS IN
DIRECT TENSION
The average strain at the level where cracking is being
considered. is assessed by calculating the apparent
strain using characteristic loads and normal clastic
lheory . Where flexure is predominanl hut some tension
exists at the section. the depth of the neutral axis should
be adjusted. The calculated apparent strain, &, is then
adjusacd to take into acccunt the stiffening effect of
the concrete between cracks Cz. The value of the
stiffening effect may be assessed from B·3, and
Provided that the strain in the reinforcement is limited
to 0.8 fiE,. the design crack width should not exceed
the appropriate value given in 8 of IS 3370 (Part I)
and may be calculated from equation (10) :
w=3a.,tl..
... (10)
where C. is assessed in accordance with U.S.
£,. = £, - 6i
U.S AVERAGE STRAIN IN DIRECT TENSION
where
The average strain is assessed by calculating the
apparent strain using characteristic loads and normal
elastic theory. The calculated apparent strain is then
adjusted to take into account the stiffening effect of
the concrete between cracks. The value of the stiffening
effect may be assessed from 8-'.
&., = IVCfale strain It the level where cracking is
being considered,
&,
strain at the level considered.
= strain at the level considered, and
6i = strain due to stiffening effect of concrete
between cracks.
B-3 STIFFENING EFFECT OF CONCRETE IN
FLEXURE
B-6 STIFFENING EFFECT OF CONCRETE IN
DIRECT TENSION
The stiffening effect of the concrete may be assessed
by deducting from the apparent strain a value obtained
from equations (8) or (9) .
The stiffening effect of the concrete may be assessed
by deducting from the apparent strain a value obtained
from equation (II) or ( 12) .
For a limiting design surface crack width of 0.2 mm:
For a limiting design surface crack width of 0.2 mm:
8
IS 3370(Part Z) : ZOO9
2b,D
b, = width of the: section at the centroid of the
tension steel,
IJ = overall depth of the member.
E, = modulus of elasticJly of reinforcement, and
A, = area of tension reinforcement.
. . . (11)
t1 = 3£,A.
For a limiting design surface crack width of 0.1 mm:
b,D
t1
~
.. . (12)
= £,A.
The stiffening effect (acton should not be interpolated
or extrapolated and apply only for the: crack widths
stated .
= strain due to stiffening effect,
ANNEXC
(Foreword)
COMMITTEE COMPOSmON
Cement and Concrete Sectional Committee, CEO 2
R~muati~l)
0rraN1D1ioft
Delhi Tourism and Transportation ~loplDall CArponrion
Ltd. New Ddhi
Stuta Jmf. KuaAH (C~)
ACC Ltd. Mumbai
SItRI NAYIla< e - A
S_ P. SalNlvASAH (AIU~,)
Atomic Energy Relul.tory Board. Mumbai
DR Pa_a C. B,ulJ
SHII L R.
8.-. (AW""",)
Building Material. and Tc:c:hnoloi)' Promotion Couecil,
New Delhi
SHI1 J. K. ...... ..."
SHII C . N . JM'" (AIt,~,)
Cement Corporation of India Limited. New Delhi
SKII R. R ~A!ClE
Cement Manuf....'1W"c:n· A-..:iaIiuo. Noida
SH.. E. N. Mu-11f"
Da S. P. OItoallA/"""",)
Central Board of Irriplioa and Powcc. New DcIbi
MDlIIEIl SEaa...."
Central Building Research Institute: (CSIR). Roork«
0.. B. K. RAIl
Da S. K. AGAaWAl. (A/,,",,*)
Central Public: Work. Dcpu1mcnt. New Delhi
Oau EMx_ (DI:sx»<)
S~ I!M»F.a (s&S) (A"'rna,,)
Central Road RCIC&Idl lnslil1llC (CSIR). New Delhi
Da RAM KUMAa
SHIu M. K. Ao.\awAi
lA/,,~,)
~ (Ovu.) (AI""",,,)
S_ SAr_ KUMAa (AI"mD")
Central Soil and MaIcriaI. Rcseardl Station. New Delhi
SHIll MULUI RATNAM
Central W.ler Commission. New Dc:lhi
o.arnoa (OCOO) CN&W)
o..rvn Ownu. (eMOO) (NW&S) (AI,motU,)
S_ N. O'A"O.WEIr.MlAN lA/_)
Conmat TcclmoloJie. Pvt lid. Kolk.t.
0. A. K. CHArJUJEI'
Constntc:tion Industry Development Council. New Delhi
SMa! P R S...... v
SHII RA., JAIN (AlI,mall')
Dc:lhi Dc:velopmcm Authority. New Delhi
SHa, A. P. s.-
Dircetoru: Genc:nI of Supplica &; Disposals. New Dc:lbi
SHIu P. K. L.o.~
En&inccn India UmilCd. New Delhi
SHlU AavlHD KUMAa
S_ A. K. MISHRA (AIII'ma,,)
Ay Ash Unit, Dcpu1mc:nl of Science &; TcdlnoloaY.
Ministry of Scic:nce &; Tc:chnoIoJy. New Delhi
Da Vi...... Ku.....
SHaJ B. 8 . Aln (AI,,",,,,,)
Stw A. K. M !tuH"..... (Allrma,,)
SMa' Ml'lttSH MA1lfI... (II//una,,)
9
IS 3370 (Part Z) : 2009
R~rr~.fm tali'·~(l )
°rrUlti:UIIUII
Gammon India Limlled . Mu~i
SHal S. A . RUlUI
SHIll V. N. HEGGAllE (AII~,.,.ar~)
GnIim J ~ LimilEd. Mumbai
SHill A. K. JAIN
SHRI M. C. AGIlA:ro'Al (Alt~,.,.al~)
SHill C. M . DoIlDt
SHill B. K. JAG£T\A (Altunal~ )
HOUIillJ IIId Urllan Development CorponIIion Umired.
Sew Dd!!i
CHAoIllMAN AND MANAGING DtIt£CTOR
Indian Bveau of Mines, NAfllUI
SIlIU S. S. OM
SHRI V. ARIIL KUMAR (Alt~mal~)
SHIU MEI:'Rl1l H...sAN (Alttmau)
SHaI L N. Am;
SHa1 D. SIllNIVASAH (All~rnalt )
"-oF V. K . GunA
IDdi.Ia Jnstjl1llC of TcchaolocY. Roortce
OIl BIM'INDF.& SINGH (Alltmat~)
Iadiaa RC*Is CongJas. New Delhi
SIDEI'AIIY GENew.
DIaJ;croK (Allernate)
Jllltil1llC fe. ResearclI. Developmenl It Trainm, of
COIISlI'IICIioa TI1Idc.. ~
OIl N. RAGIlAVf.NllaAo
1JIIti11llC fe. Solid WMac RClCal'Ch &; EcoiOlicaJ Balance.
OIl N. BI:ANUMATlllDAS
S_ N. K.u.JrMs (AIIU71l/1t)
VisakhapImam
M8dr.- e-ta Lad, 0IcMai
SHaI V. JALiANAT1WI
SHRI BAUJI K. MOOCTHY (Alremare)
MiJiwy ~ Scnica. EapDecr-ia-Cbiers BI'lIDCh,
AzfII'J .......1EiS, New Ddhi
Slw J. B. SitAaNA
Sua YOOI!SK Saow. (AlrenttJU)
MIlIislry of R_ T...-port A HipwaY$. Nao Delhi
S..u A. N. DltooAPt.Aa
S- S. K. PulU lAl1enttJU)
NMMIaaI e-'iI for <:-1 ..t BlIiIdlllJ MaIuiaIs,
SHRI R. C. W...-
Da M. M. Au (Altemar~)
BaIIaIII-fl
N_ _ lac Houc. Kol.bla
SHRI B. R. MWIAo
S _ n S. A. KAusml (Alrel'1ll/lt)
Slllu U. S. P. Vf.&MAo
SMa! AJMNll SHRIVATIlYA (AI,~I'7ItIIl!)
OCt. IIIlIia UaUred. New Delhi
OIl S. C. AHLuwAuA
hblic WOIb DLpal-' Gowcnunca« of ~ MlIIIIbM
~.\TIVll
~Iic; WuRs 0epw1me... GcnemlllCat of Tarail N8du.. Oteanai
SUP£IIIImMlDlO ENoiNmt (DEsKiN)
ExIlC\1TM ~ (A1ltmal~)
~ Oaip ol sc-a.rdI Orpnizalioa (Minillry of Railways).
lAd:_
Sanpai laduslrlea Limilrd. Sanp Nap. Ranp Reddy Disrricl
SHRI R. M. SHAo.....
SMa! V. K. YAllAYA (Alk/lltlll!)
SHRI D. B. N. RAO
OIl H. K. PIITlWIt (Allt/lltlll!)
OaF fMcDe!a (NA~ DAM)
~ I!lGNEEa (Alul'7llZk)
SHIt, A. C!tEu.APrluI
S-J .~WIl!_)
s.rS .~
S-R .~~)
s.. P. D. ICaLo\I
S- S. J. Sawt (AlunlQll!)
OIl H. C. VISVESYAilAYA
S- 8IIuta s.o. (AIIl!/lIaIe)
s.r SuuKro e-n.un
S- 8&swMT DHAa (Alk~)
10
IS 3370 (Part 2) : . ,
R~p"sn"rJ"w(I)
OrgUltilJll lO"
VolunW)' Organ iution in (nteresl of CQlUUmer Ed.la&iOll,
New Delhi
Slcll HUONfT Kl '.....
BIS Directorate General
SMa A. K. SAlHl . Scielltill "F' &t Head (a~ Eng)
[Il~ull Diftdot Gmt:nI (EJ"'~o.?ll
M~~, ~"'?Iari"
S..., SANJn PANT
Scicntill ' E' &. Direclor (Cj~ Enul. BIS
SHR I S . AIllIN K l ......
Scjenris; ' B ' (C iv En"I. BIS
Concrete Subcomm ittee . CEO 2 : 2
Delhi Tourism &. Transportation Developmcnl Curporation
LId. New Delhi
ACC Ltd. Mumbai
S... ANIL BANClMlll
S- P. B~AY (Alk_)
AlOmic Energy Rcgularory Board, Mumbai
OIl Pa.-. C. Buu
S- L. It 8-.Jl (A1u_)
Buildin! MaIeriaIs and TedInoloc Promotion Council.
New Delhi
S- J. K. I'LuAo
S- pAlCAJ 0\wrA (A~)
Cenlrll Building Research Institute (CSIR). Roortce
OIl B. K. RAD
OIl S. K. Aa.uIw.L (AIu_)
Cenlrll Public WOIb Deputmcnl. New Delhi
S~E..-(o-..)
CcnuaJ Rl*! Resean:h Inllitute «('SIR). Ne-A' Delhi
OIl~MA~
Cenlrll Soil &. Materials Resean:h Sl.IlIon . New Delhi
SJe. MI-.uD RATMAM
S. . N. ClwolIlAJQQI.IMI (AI"_I
Ccnlnl Waler Commission . New Delh i
D1aIIl"TlJl (C&-.MDDI
Engincen India Limited. New Delhi
S_ Ar.vvoo KlIMA.
s... T. BAIAAI <AIU-I
A)' Ash Uttil, Dep.tmmt of Science Md TcchnoloJY.
Minislry of Science &. lCdInoIOC. New Delhi
DI V/MAl. KUMA.
S- MUUSIl MA11tlJlI ~rl
Gammoa India Limitlod. Mumbai
S_ S. A. kBlDl
OIl N. K. NAYAI (All",,,,,,)
Grasim Industries LId. Mtunbai
SIeI A. K. JAIN
S- M. C. AoaA.". (Alumalrl
Gujarlll Ambaja Cement Limited, Ahmedabed
s.. C. M. DoaDI
s.. B. K. JAamA (AI,._)
ExIlCVl1VZ e..-~)~)
S- S _ K _ (A,.. . .)
0Durt DlIInoI (eaMDD) lAW-I
.... M . S SIlETrt
S- L. N. An-. (Allr_)
Oa B. BtlATTACKAIJIl:
Indian InstitulI: of TedlnolO!)'. Kanpur
Indian Instit1Ite of TecbnoloV. Roortee
OIl AsNOIl K\IIlIIAIl JAIN
Lanen IIld Toubro Limitrd., Chcanai
OIl B. StvUAlo4A S _
s.. ICJM;suy J. D. e-r (AII~_)
Militar)' Engineer ~ Eogineer·in-Cbier. Branch.
Army Hcadqunm. New Delhi
Bll c R. K. ~A
Cot. V. K. BADGI..... (,,"'_)
11
IS 3370 (Part 2) : 2009
Representativeis}
OrganillJli()fI
Ministry of Road Transport and Highways. New Delhi
SHRI T. B. BANERlf£
National Buildings Construction Corporation Limited.
New Delhi
SHRI L. P. SINGH
National Council for Cement & Building Materials.
Ballabgarh
SHRJ R. C. WAS ON
SHRI H. K. JULKA (A//emale)
National Institute of Technology. Warangal
DR C. B. KAMESwARA RAO
SHRl KAMI£SH KUM AR (A/lemale)
SHRI DARSHAN SINGH (A/lema/e)
OR D . RAMA SESHU (A/temalt)
Nuclear Power Corporation of India Limited, Mumbai
SHRl U. S. P. VERMA
Pidilite lnduslries Limited, Mumbai
SHRI P. L. PATRY
SHRl ARvlND SHRIVATAVA (Alltmale)
SIlIlI K. PADMAKAR (Alltmate)
Ready Mixed Concrete Manufacturers' Association. Bangalore
SHRI VUAYKUMAR R. KULKARNI
Research, Design &: Standards Organization (Ministry of Railways),
JOIKT DnlEcroR STANI>AIlDS (B&:S)/CB-I
Joorr DtIlECTOll STANa"RDS (B&S)/CB-!1 (Alternate)
Lucknow
SHRI T. S. KRISHNAMOORTHY
Structural Engineering Research Centre (CSIR). Cbennai
SHRI K. Bf\LMUBRAMANlAN (Alternate)
Tandon Consultants Private Limited, New Delhi
SHRI MAHESH T ANOON
TCE Consulting Engineers Limited. Mumbai
SHRI J. P. H"RAN
Torsteel Research Foundation in India, New Delhi
DR
In personal capacity (35. Pari. AvenI/e. Annamma,
Naid:er St~et. KJutiamuthllr, Coimbato~)
DR C . RAlKUMAR
In personal capacity (36. Old 5Mh Nagar, Wardha Raad.
Nagpl/r)
SHRI Lurr KUWAR JAIN
SHRI VINAY GuPTA (A/temate)
SHRI S . M. PAlEK"R (Altemate)
P. C. CHOWDHURY
DR C. S. VL~HWANATHA (Altemate)
Panel for Revision errs 3370 (Parts 1 and 2). CED 2 : 2JPI
National Council for Cement and Building Material.
BaIlabgazh
OR ANn. KUMAR (CoMerur befo~ 18 October 20(6)
In persoaaI capacity (36. Old 5Mh Nagar, Wardha Rood.
Nagpl/r)
SHRI LALIT KUMAR JAIN (CODetlU since /8 October 20(6)
Central Road Researm Institule (CSlR). New Delhi
DIRf.CTOtl
Delhi Tourism and TransportAtion Development Corpontion
SIlIlI JOSE KURIAIl
SHRI SATANDfJl KlJMAIl <Alternate)
Ltd, New Delhi
Gammon India Ltd, Mumbai
SHRI S . A. REDOI
Indian Institute of Technology, New Delhi
OR S. N. SII'lIlA
lndia:1 Institute of Technology, Roorkee
DR AsHOK
Military Engineer Services. Engineer-in-Chiefs Branch.
Anny Headquarters, New Delhi
SHRI J. B. SHARMA
Nalioaal Council for Cement and Building Material.
SIlIlI H. K . JUlKA
SIlIlI R. C. WASON (A.lurnate)
K. JAIN
SHRI YOGESH K. SINOHAl (A/ternate)
BaIIabgarh
Scbool of Planning aDd Architecture. New Delhi
OR V. TIURUVEN<JAD.\M
Stnx:tDJa1 Engineering Resarch Centre (CSIR). Olcnnai
SHRlT.S .~
TCE Consulting Engineers Limited, Mumbai
SHIll S. M. Pf\WWl
SHRJ S. KmHNA (A/temate)
In personal capacity (K-U2. Kavi NalIar, GhcWabat!)
OR A. K. MmAL
SHRI K. BAlASIIB&AMANIAN (A.lternate)
12
Bureau of Indian Standards
BIS is a statu lory institution established under the Bureau of Indian Standards Aer, 1986 to promote
harmonious development of the activities of standardization, marking and quality certification of good s
and attending to connected mailers in the country .
Copyright
BIS has the copyright of all its publications . No part of these publicati ons may be reproduced in any form
without the prior permission in writing of BIS . This does not preclude the free lise. in the course of
implementing the standard. of necessary details, such as symbols and sizes. type or grade designati ons.
Enquiries relating to copyright be addressed to the Director (Publications). BIS.
Review of Indian Standards
Amendments are issued to standards as the need arises on the basis of comments. Standards are also reviewed
periodically; a standard along with amendments is reaffirmed when such review indicates that no changes are
needed; if the review indicates that changes are needed, it is taken up for revision . Users of Indian Standards
should ascertain that they are in possession of the latest amendments or edition by referring to the latest issue of
'BIS Catalogue' and 'Standards: Monthly Additions' ,
This Indian Standard has been developed from Doc No.: CED 2 (7330).
Amendments Issued Since Publication
Amend No .
Date of Issue
Text Affected
BUREAU OF INDIAN STANDARDS
Headquarters:
Manak Bhavan, 9 Bahadur Shah Zafar Marg, New Delhi 110002
Telephones: 2323 0131.2323 3375,23239402
Website: www.bis.org.in
Regional Offices:
Telephones
Central
Manak Shavano 9 Bahadur Shah Zafar Marg
NEW DELHI 110002
Eastem
1/14 C.I.T. Scheme VII M, V. I. P. Road, Kankurgachi
KOLKATA 700054
Northern
sca 335-336 , Sector 34-A, CHANDIGARH 160022
Southern
C.I.T. Campus, IV Cross Road, CHENNAI600113
2254 1216,2254 1442
{ 225425 I9,22542315
Western
Manakalaya, E9 MIDC, Marol, Andheti (East)
MUMBAI400093
{2832 9295, 2832 7858
28327891, 2832 7892
Branches:
AHMEDABAD. BANGALORE. BHOPAL. BHUBANESHWAR. COIMBATORE. FARIDABAD.
GHAZIABAD. GUWAHATI. HYDERABAD. JAIPUR. KANPUR. LUCKNOW. NAGPUR.
PARWANOO. PATNA. PUNE. RAJKOT. THIRUVANANTHAPURAM. VISAKHAPATNAM.
2323 76 17
{ 23233841
23378499,23378561
{ 23378626.23379120
60 3843
{ 609285
PRINTED BY THE GENERAL MANAGER. GOVT. OF INDIA PRESS. NASHIK-422006