A Seismic Response Analysis of a Cylindrical Liquid Storage Tank Including the Effect of Sloshing

A seismic response analysis method for a cylindrical liquid storage tank subjected to a horizontal earthquake is presented in this paper. The kinetic and strain energies of an empty tank shell are estimated assuming it as an axisymmetric shell. The virtual work of liquid pressure exerting on the tank wall is also estimated analytically by assuming that the behaviour of the liquid follows the velocity potential theory which includes the effect of sloshing. The Lagrangian formulation for the coupled vibration is then derived. Coupling this equation with the Bernoulli equation for the boundary condition of a liquid free surface, an eigenvalue analysis method for the coupled vibration can be obtained. And, a seismic response analysis method is also made using the exciting energy due to a seismic wave. As a result of numerical studies, this solution is proved to be an effective and reasonable method for the seismic response analysis of a cylindrical liquid storage tank.