Abstract: Safe drinking water is one of the basic elements for humans to sustain healthy life. Reinforced concrete overhead
water tanks are widely used to provide safe drinking water. Most water supply systems in developing countries, such as India,
where urbanizing is increasing day by day, rely on overhead storage tanks and hence there is need to construct more number
of water tanks. Earlier design of water tanks was done using the working stress method given in IS: 3370 1965. This method
leads to thicker and heavily reinforced sections. The use of limit state method of design was then adopted in the revised code
IS 3370: 2009 and provision for checking the crack width was included in the code. This study is carried out to analyze the
cost of overhead water tanks of a fixed capacity, having different heights and diameters so as to determine the most
economical height to diameter (H/D) ratio to be adopted in the design of the tank. To optimize the results and check the
accuracy of design, six circular water tanks of 500 kL, with top and bottom dome pattern, were designed by varying H/D ratio
from 0.15 to 1.05 in STAAD. Pro. After assuring the safety of all the structures, further analysis is done to calculate the costeffectiveness
of the structures by comparing the approximate total cost of materials. It was found that the aspect ratio (H/D)
of 0.60 led to the most efficient design.
Keywords: Water tank, Earthquake, wind load, Hydrostatic load