The influence on seismic response of base-isolated liquid storage tanks for different shapes of isolator hysteresis loop has been investigated herein. Ground supported base-isolated liquid storage tank is modeled using the mechanical analog with three lumped mass-es, and analyzed for earthquake ground accelerations. The non-linear force-deformation be-havior of the isolator is mathematically modeled in two different ways, represented by (a) bi-linear hysteretic and (b) equivalent linear elastic-viscous behaviors. The coupled differential equations of motion for the isolated system are derived, and solved in the incremental form using Newmark’s step-by-step method of integration. Two different configurations of liquid storage tank (i.e. broad and slender) are considered to show the effect of the linear and bi-linear modeling of the isolator on the important seismic response quantities. The influence of the shape of isolator force-deformation loop on seismic response of the base-isolated liquid storage tank is studied for different values of characteristic parameters of the isolator. The characteristic parameters are taken as the isolator yield displacement, isolation time period, characteristic strength of the isolator etc. It is observed that there is significant difference in the seismic response of the isolated liquid storage tanks owing to the two modeling approach-es, such as the bi-linear hysteretic model and the equivalent linear elastic-viscous damping model. The response of base-isolated liquid storage tanks are significantly influenced by the shape of hysteresis loop of the isolator.

Earthquake, Hysteresis, Isolation, Seismic, Tank.