Beam Model for Base‐Uplifting Analysis of Cylindrical Tanks

Abstract

Free‐standing, unanchored liquid‐storage tanks have the tendency to lift off their base under the overturning influence of the hydrodynamic wall pressures generated during earthquakes. Fundamental to the analysis of these systems is a detailed investigation of the behavior of the partially uplifted base plate. As a step to such an investigation, a comprehensive analysis is made herein of the uplifting resistance of a uniformly loaded semiinfinite prismatic beam that rests on a rigid base. The analysis used represents an improvement over the previously proposed methods in that it provides for the effects of both material and geometric nonlinearities in a realistic and cost‐effective manner. The results presented demonstrate the importance to the load‐carrying mechanism of the membrane forces induced by the constraining action of the tank wall. An in‐depth parametric study elucidates the effects of the various system parameters on the uplifting resistance of the beam.