Seismic response of base isolated liquid storage tanks to real and simulated near fault pulse type ground motions

Abstract

In this paper, the seismic response of base-isolated liquid storage tanks subjected to real and simulated near-fault ground motions is investigated. It is assumed that the tanks are seismically isolated by single surface Concave Sliding Bearings (CSB) with different isolation periods. For the input data, the recorded and simulated ground motions having pulse type characters and their dominant waveforms are considered.For each case considered, numerical analyses are carried out to calculate the critical demand parameters such as base shear values, bearing and sloshing displacements of the tank. The results revealed that, the base shear response of the slender tank to real and simulated ground motions and equivalent pulses tend to approach each other at isolation periods around 3 s and then remain constant in higher periods. Similar findings are not observed for the broad tank. Depending on the special case considered in this study, it can be said that, for the preliminary design of slender tanks in the near-fault regions, the real earthquakes can be replaced by equivalent pulses especially for isolation periods larger than 3s.