The document compares the design of circular and square water tanks using the working stress method and limit state method. It was found that: 1) The limit state method requires less steel than the working stress method for both circular and square tank designs. 2) A circular tank design is more economical than a square tank design due to requiring less steel. 3) The limit state method results in a more rational and economical design compared to the traditional working stress method.

1. International Journal of Research in Advent Technology, Vol.2, No.8, August 2014
E-ISSN: 2321-9637
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Comparative Study of Water Tank Using Limit State
Method and Working Stress Method
Miss. Neeta K. Meshram1,Dr. P.S.Pajgade2
M.E. student, Dept. of Civil Engineering1,PRMITR,Badnera,Amravati, Maharashtra state, India1
Professor of civil Engg2.,PRMITR,Badnera,Amravati, Maharashtra state, India2
Email:Neetameshram17feb@gmail.com1, ppajgade@gmail.com2
Abstract: Water tanks are liquid storage containers. These containers are used for storing water. Water tanks are
traditionally designed by working stress method. As per revised IS 3370 water tank can also be designed by limit
state method .In this dissertation water tanks are designed by both working stress method and limit state method.
Circular and square water tank are considered .Detailed analysis and design is done. Working drawings are prepared
for all conditions. For understanding the financial implications quantities for concrete and steel were calculated.
Exact amount of steel required is calculated for each case as per working drawings.
It was observed that in case of limit state design cost required is less. Obviously circular water tank is more
economical compare to square tank.
Index Terms-Water tanks, working stress, limit state.
1. INTRODUCTION:
Water tank are liquid storage containers. These
containers are usually storing water for human
consumption. The need for water tank systems is as
old as civilized man. A ground water tank provides
for the storage of drinking water, irrigation, fire
suppression, agricultural farming and livestock,
chemical manufacturing, food preparation, rainwater
harvesting as well as many other possible solutions.
The common materials used for the construction of
water tank are concrete, steel and masonry. RCC is
commonly used in construction because it is
supposed to be durable material giving long
maintenance free service.
In general, service reservoirs can be classified;
Ground service reservoir
a) Cylindrical service reservoir
b) Rectangular service reservoir
c) Square service reservoir
1.1 Ground Service Reservoir –
Reservoir is common term applied to liquid storage
structure and it can be below or above the ground
level. They have circular, rectangular and
squaresections with flat bottom slab. The joint
between floor and wall are of two types i.e. flexible
joint between floor and wall and second rigid joint
between floor and wall.
Method of Analysis and Design – The behavior of
walls of water tank is more complex. They need
sophisticated methods of analysis. For cylindrical
tank, bending theory of cylinder with different edge
conditions is required. For square tanks, plate theory
with approximate boundary conditions at the four
edges gives better results.IS3370 gives the design
tables to pick up moment and shear coefficients for
the design of cylindrical as well as square walls.
1.2 Design Requirement–
In this paper following code are used :
1) IS 3370 part 1&2:2009 is the Indian code of
practice for Concrete structure for the
storage of liquids.
2) IS 456 : 2000
3) IS 3370:1965 Part IV – Design tables
To avoid leakage problems IS 456 guide lines
shouldbe used, which is based on working stress
method. The strength and imperviousness achieved
by using richer concrete mix say M25 and M30. Give
a minimum clear cover of 40 mm, provide smaller
diameter bars at closer intervals, keep the tensile

2. International Journal of Research in Advent Technology, Vol.2, No.8, August 2014
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stress in concrete low and follow good construction
practices like through mixing good compaction
andgood curing. In this paper results of analysis and
design of general service reservoir of circular and
square shape by using guidelines given in IS codes
are presented .
Firstly analysis and design of circular water tank is
to be done by using IS 3370(2009) & IS 456 : 2000
code method . The cases considered are circular tank
with rigid joint between floor and wall. Secondly
analysis and design of Square water tank isdone by
using same IS code mentioned earlier. The design
and cases are similar as that of circular ground
service reservoir. Then estimate of quantities required
for water tank is calculated to identify economical
design. The results are presented analytically and
graphically.
Fig.: 1 Circular Ground Water Tank

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2. REINFORCEMENT DETAIL:-
Fig.2 Circular water tank by LSM
Fig.3 Circular water tank by WSM

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3. ESTIMATE OF WORK:
Table: 1Steel quantity required
Description Method Steel Quantity
Kg
Circular water
tank
WSM 1959.87
LSM 1523.44
Square water tank WSM 3889.42
LSM 3261.78
STEEL QUANTITY (Kg)
Fig.4 Steel Quantity For Various Shape
Table 2- Cost of steel for water tank :-
4500
4000
3500
3000
2500
2000
1500
1000
500
Description Method Cost
55 Rs/ Kg
Circular water
tank
WSM Rs.107792.85
LSM Rs. 83789.2
Square water
tank
WSM Rs. 213918.32
LSM Rs. 179397.68
0
Circular
W.T. By
WSM
Circular
W.T. By
LSM
Square
W.T.By
WSM
Square
W.T.By
LSM
STEEL
QUANTITY
(Kg)

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Fig.5 Cost for steel Quantity
250000
200000
150000
100000
50000
4. RESULT AND DISCUSSION
· The steel quantity found more for a circular
service reservoir design by WSM than that of
LSM.
· The steel quantity found more for a square
service reservoir design by WSM than that of
LSM.
· The Circular shape is found to be more
economical than square shape.
· The recent introduction of the limit states
method of design in IS 3370 Part 2:2009 and IS
456 : 2000 (with crack width limit of 0.2 mm) in
line with international codes of practice is found
to results in more rational and economical design
compared to the traditional working stress
method.
REFERENCES
[1] Prof. R.V.R.K. Prasad, Akshaya B. Kamdi,
‘Effect of revision of IS 3370 on water storage
tank’, International Journal Of Engineering
Research and Application (IJERA), Vol.2, Issue
5, September – October 2012 , pp.664 – 666.
[2] William H. Hartt, PhD, ‘Effect of concrete crack
width on corrosion of embeddedreinforcement’,
PE Hartt and Associates, Inc. 20914 Morada
Court Boca Raton, Florida 33433, March 18,2009.
[3] G.Hemalatha ,J.Tejaswi, ‘Design of R.C.C. Over
headtank’ ,GRIEAT, Hyderbad 2012.
[4] Phanisri P. Pratapa and DevdasMenon, ‘Optimal
design of cylindrical reinforced concrete water
tanks resting on ground’pg19-25, Feb 2011, The
Indian Concrete Journal.
[5] Munshi J.A. and Sherman W.C., ‘ Reinforced
concrete tanks’pg.101-108, Feb2004, Concrete
International Journal.
[6] Ashok K. Jain, ‘Reinforced concrete Limit State
Design’, pg.196-197, pg.671-677,
Nem Chand & Bros.,Roorkee 247 667,India.
[7] IS 3370 (Part–I,II) “Code of Practice for Concrete
Structures for the Storage ofLiquids”, Bureau of
Indian Standards, New Delhi, 2009
[8] IS 3370 (Part–IV) Design table, “Code of
Practice for Concrete Structures for theStorage of
Liquids”, Bureau of Indian Standards, New
Delhi.1967.
[9] IS 456, “Code of Practice for Plain and
Reinforced Concrete”, Bureau of Indian
Standards, New Delhi, 2000.
[10] SP:16, “Design Aids For Reinforced Concrete
Design” To IS : 456.
0
Circular
W.T. By
WSM
Circular
W.T. By
LSM
Square W.T.
By WSM
Square W.T.
By LSM
Cost in Rs.
Cost in Rs.