Seismic frequency content as a key parameter in the dynamic buckling behavior of tall thin-walled steel tanks

The dynamic buckling behavior of anchored thin-walled steel storage tanks subjected to seismic excitation is investigated, with particular emphasis on the influence of seismic frequency content. Nonlinear analyses are performed on a representative anchored cylindrical tank with an aspect ratio H/D=2, selected for its practical relevance and known susceptibility to diamond-shaped local buckling. Three recorded ground motions with distinct frequency characteristics -Boumerdes, -Parkfield, and -San Fernando, are employed to evaluate their effects on seismic response and buckling of tank. The numerical results reveal the development of diamond-shaped local buckling modes concentrated in the upper shell courses, with buckling occurring at PGA levels of 0.16 g, 0.11 g, and 0.76 g for the Boumerdes, Parkfield, and San Fernando records, respectively. These findings demonstrate that earthquake frequency content plays a governing role in the dynamic stability of thin-walled steel storage tanks and should be explicitly considered in seismic response and buckling assessments.