Seismic analysis of steel liquid storage tanks by Endurance Time method

Endurance Time (ET) method is a time history based method for seismic evaluation of structures using intensifying dynamic excitation as the loading function. In this paper, application of this method in the analysis of steel tanks has been investigated. A methodology for practical application of ET method in seismic assessment of storage tanks has been presented. This methodology has been applied in three-dimensional nonlinear analysis of a particular anchored steel tank using Finite Element method, and results are compared with conventional codified design procedures. Results of the analyses indicate reasonable accuracy of the proposed method in estimation of seismic responses of steel tanks and its applicability in enhancing the design process of steel tanks considering various sources of complicated behavior. Comparative study of seismic response of the tank in anchored and unanchored states utilizing ground motions has been presented. Advantages and limitations of the procedure have also been discussed.