Dynamic behavior of liquid storage tanks

A correct analytical prediction of experimentally found mode shapes and frequencies has been obtained for a thin-wall storage tank of French PWRs filled with water. A series of shake table tests with increasing excitation level borated or feedwater have been performed up to obtention of buckling under vertical and horizontal earthquake acceleration. A static calculation of the tank buckling has lead us to a better understanding of what is considered as the dominant failure mechanism of thin-wall tanks under horizontal seismic acceleration, i.e., buckling under shear and compressive stresses at the base of the tank. Further calculation are being performed in order to investigate the effect of wall shape defects and better predict the level of acceleration which lead to buckling. (orig./HP)