Strength of Welded Connections in Unanchored Steel Liquid Storage Tanks Under Seismic Loading

The present work is part of an extensive European research program and examines the low-cycle fatigue resistance of the shell-to-base welded connections in unanchored steel tanks. Eight tests on fillet welded shell-to-base connections representing a prototype liquid storage tank were performed to evaluate their inelastic behavior under strong cyclic conditions. In all welded connections S275J2 grade was used for the base plate and S355J2 grade was used for the shell plate. Two different weld thicknesses were considered and a total of four displacement-controlled constant amplitude loading schemes were applied. Numerical models of the welded connections were also developed using ABAQUS finite element software, accounting for material and geometrical nonlinearities. The models were validated against the test results, which they matched closely. The analysis results basis was further expanded through a parametric analysis focusing on different weld sizes and different material grade allocation.