Seismic performance of imperfect unanchored tanks

Liquid storage tanks play a significant role in storing hazardous liquids in process industries. Hence, their proper seismic performance is considerably important to prevent the catastrophic consequences of tank failure. This study focuses on seismic safety assessment of oil storage tanks. To this end, four unanchored tanks of various height-to-diameter ratios (H/D) were considered and their elastic and inelastic buckling failures were studied, as well as their uplifting behaviour. To this end, incremental dynamic analysis was employed in an Abaqus platform using the lateral seismic excitations. Different patterns of random geometric imperfections of various amplitudes were considered in the tank models. The Budiansky–Roth procedure was followed to calculate the buckling capacities of tank shells. The results of this study revealed that the imperfection has a small but notable effect on buckling capacity of tank shells, but its effect on tank uplift is negligible.