Dynamic Characteristics and Seismic Response Analysis of Rectangular Tanks

Liquid storage tanks are important structures being used in various industries, potable water supply, irrigation, etc. Such tanks are typically constructed with different plan shapes, e.g., rectangular, square, circular, etc., having different slenderness ratio. The present study investigates the dynamic characteristics of ground supported rectangular tanks and their response under seismic excitation. The objective of this study is to compare the dynamic characteristics and seismic responses obtained following the code provisions (Indian standards) and those obtained using detailed 3-dimensional (3D) finite element (FE) analysis. Different slenderness ratio and aspect ratio of the tanks are considered in the present study. Rectangular tanks are modeled using (i) simplified mechanical lumped mass (LM) following Indian standard provisions and (ii) 3D-FE approach. Finite element modeling of the rectangular liquid storage tanks is carried out using coupled acoustic-structure (CAS) interaction approach. It is observed that the peak sloshing response is significantly underestimated by the lumped mass model recommended by the Indian standard, in comparison to the 3D-FE model in the case of both broad and slender tanks.