International Journal of Research in Advent Technology, Vol.2, No.8, August 2014 E-ISSN: 2321-9637
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;
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.
Ground service reservoir
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
a) b) c)
Cylindrical service reservoir Rectangular service reservoir 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
1.2 Design Requirement–
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International Journal of Research in Advent Technology, Vol.2, No.8, August 2014 E-ISSN: 2321-9637 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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International Journal of Research in Advent Technology, Vol.2, No.8, August 2014 E-ISSN: 2321-9637 2. REINFORCEMENT DETAIL:-
Fig.2 Circular water tank by LSM
Fig.3 Circular water tank by WSM
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International Journal of Research in Advent Technology, Vol.2, No.8, August 2014 E-ISSN: 2321-9637 3. ESTIMATE OF WORK: Table: 1Steel quantity required Description
Method
Circular water tank
WSM
Steel Quantity Kg 1959.87
LSM
1523.44
Square water tank
WSM
3889.42
LSM
3261.78
STEEL QUANTITY (Kg) 4500 4000 3500 3000 2500 2000 1500 1000 500 0 Circular W.T. By WSM
Circular W.T. By LSM
Square W.T.By WSM
Square W.T.By LSM
STEEL QUANTITY (Kg)
Fig.4 Steel Quantity For Various Shape
Table 2- Cost of steel for water tank :Description
Method
Cost 55 Rs/ Kg
Circular water
WSM
Rs.107792.85
tank
LSM
Rs. 83789.2
Square water
WSM
Rs. 213918.32
tank
LSM
Rs. 179397.68
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International Journal of Research in Advent Technology, Vol.2, No.8, August 2014 E-ISSN: 2321-9637 Cost in Rs. 250000 200000 150000 100000 Cost in Rs.
50000 0 Circular W.T. By WSM
Circular Square W.T. Square W.T. W.T. By By WSM By LSM LSM
Fig.5 Cost for steel Quantity
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.
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