SEISMIC ANALYSIS OF LIQUID STORAGE TANKS BASED ON DYNAMIC PUSHOVER METHOD

To effectively assess the seismic capability of liquid storage tanks in the elastoplastic stage, the equivalent dynamic equations of a fluid-solid coupled system were established by condensing the pressure degrees of freedom in a fluid domain, the projection equation for a spectral acceleration-displacement capacity curve was then derived, based on generalized inverse theory after merging the vibration modes with the corresponding frequencies, and the unidirectional dynamic pushover of the fluid-solid coupled system was realized by controlling the harmonic parameters, by which the capacity curve was determined and used as a generalized constitutive model with a single degree of freedom for liquid storage tanks. The time history analysis showed that the hysteretic curves and time history results of above generalized constitutive model were quite consistent with those of the fluid-solid coupled system, and the tank stiffness degenerated progressively. The proposed method consumes relatively similar computation time as a static pushover method, and eliminates the influence of the characteristic node on the capacity curve, and can consider the distribution change of tank resistance forces in the elastoplastic stage.