Dynamic analysis of rectangular liquid containers in three-dimensional space

A new method for seismic analysis of containers in three-dimensional space is introduced in which the effects of both impulsive and convective components and their corresponding damping are accounted for in time domain. A case study is performed to investigate the behaviour of a concrete rectangular container under the effects of horizontal and vertical ground motions using the scaled earthquake components of the 1940 El-Centro earthquake record. Two-dimensional behaviour of the tank is assumed. The results of the study are compared with those obtained using the current practice and those determined from finite element (FE) analysis based on a lumped mass model. The results of the FE analysis with the equivalent added masses and rigid walls are in good agreement with those from the current practice. Compared with the proposed method, however, the current practice overestimates the response of the container. Also, the vertical excitation leads to a significant response in the container, but combining the effects of horizontal and vertical excitations reduces the response of the structure in the considered system.