Seismic performance of base-isolated liquid storage tanks is evaluated through development of fragility curves. The current study presents a procedure to find the demand and capacity of base-isolated liquid storage tanks under non-stationary stochastic earthquake, which has not been addressed adequately in the literature. The limit state of failure is defined with respect to the axial compessive strength of the tank wall. The criterion for the limiting stress, leading to the structural failure, is taken from the available literature an international codes for design of liquid storage tanks. The uncertainty involved is considered in the earthquake characteristics only. Considerable deviation is observed in the fragility curve for fixed-base and base-isolated liquid storage tanks. Parametric studies show that probability of failure for the base-isolated liquid storage tanks increases with: (a) increasing liquid height, (b) decreasing isolator time period and (c) decreasing isolator damping.

Base Isolation; Liquid Storage Tanks; Seismic Fragility.