Low-Cycle Fatigue of Base-Plate-to-Shell Connection in Uplifting Liquid Storage Tanks Under Seismic Loading

Abstract

Unanchored steel tanks, subjected to strong seismic loading, may exhibit base plate uplifting. Under repeated uplifting, the welded connection of the tank base plate with the tank shell (a fillet-welded connection) is subjected to strong cyclic deformation, involving reverse plastic loading, and this could lead to failure of the welded connection in the form of low-cycle fatigue cracking. In the present paper, an experimental program is described, supported by numerical finite-element simulations. The tests are aimed at investigating the mechanical response of small-scale welded specimens, representing the connection of the base plate with the tank shell, subjected to uplifting loading conditions. The research has been partially supported by European research project INDUSE-2-SAFETY, on the seismic safety and resilience of critical components in industrial plants.