Seismic response of base isolated liquid storage ground tanks

In this paper, the seismic responses of base-isolated broad and slender cylindrical liquid storage ground tanks are investigated. Three types of isolation systems are considered. The seismic responses are compared with the corresponding responses of non-isolated tanks. Moreover, a parametric study was conducted to evaluate the effect of tank aspect ratio, isolation period, and friction coefficient of the FPS system on key responses of the tank. It was found that, base isolation is quite effective in reducing the earthquake response of ground liquid storage tanks. Generally speaking, 50-90% reductions in both base shear and impulsive displacement responses were observed. The convective displacement was observed to be 20-70% higher than that associated with fixed base tanks leading to an essential need of increasing the clear height above the liquid surface. Base isolation was found to be more effective for slender tanks in comparison with broad tanks.