Effect of Soil-Structure Interaction on the Seismic Response of Elevated Water Tank

Abstract

The elevated tanks are the most critical and strategic structures since the tank contains heavy fluid mass and is placed on a slender staging. The foundation transmits the loads from the superstructure to the subsoil, and the displacement of the soil influences the response of the structure. Therefore, it is important to study the seismic response of liquid storage tanks with the incorporation of soil-structure interaction (SSI). This study aims to find the importance of the effects of supporting soil medium in the response of the water tanks. An elevated intze water tank of capacity 7,00,000 L on frame type staging was modeled and analyzed by considering SSI in finite element software ANSYS. To incorporate the effect of SSI, rock, dense, stiff, and soft supporting soil strata were considered. The infinite extent of soil was modeled using viscous boundaries. The transient analysis was carried out for the 3D liquid tank models with different supporting soils using Kobe earthquake data. The base shear, base moment, and structural displacements were found with the variation of depth of fluid inside the tank for all the models. The results showed that the maximum base shear and the base moment were observed in a tank resting on hard soil for the completely filled condition of liquid. The displacements are higher in the case of tanks resting on soft soil.