Comparison of Seismic Behavior of Rectangular Elevated Water Tank

Water tank is considered to be one of the most important structures in earthquake event. Elevated water tank consists of staging and large mass concentrated at top of staging whereas ground supported tank rest on firm ground. Behavior of water tank on staging is crucial and needs to be evaluated. For the analysis of water tank different analysis techniques are available, the main aim of analysis is to calculate seismic base shear and corresponding overturning moments at base of staging. Indian standards, IS 1893:1984 and IS 1893:2002 elaborates the procedure for calculating seismic forces for elevated circular and rectangular water tanks. For evaluating hydrodynamic effect spring mass model consisting of convective and impulsive masses lumped at different levels can be used. In this chapter it is intended to analyze rectangular water tank resting on staging by different analysis techniques viz Equivalent static analysis, response spectra analysis and linear time history analysis. The main aim is to evaluate the performance of water tank under static seismic load as well as different acceleration load. The different analysis techniques are also briefly described. The analysis is carried out with the help of ETABS analysis package.