Experimental investigation on a novel base-isolator for ground supported liquid storage tanks

The dynamic analysis of ground-supported rectangular liquid storage tanks (LSTs) with base isolation, using steel core and filler bearings, is conducted experimentally and numerically through the finite element method. Five types of bearings are designed for the selected tank geometry, namely laminated rubber bearing, sand-filled rubber bearing, coir-filled rubber bearing, steel core-sand filled rubber bearing, and steel core-coir filled rubber bearing. LST models with these bearings are fabricated and tested on a shake table under harmonic motion. The models are also analyzed numerically in ABAQUS using a coupled acoustic-structural approach to examine fluid–structure interaction behaviour and compare with experimental results. Seismic response parameters, including convective displacement, hydrodynamic pressures on the tank wall and base, and bearing displacements, are investigated under harmonic motions. The designed bearings significantly reduce hydrodynamic pressures compared to standard laminated rubber bearings. Specifically, the base isolator with steel core-coir filler reduces the hydrodynamic pressure by more than 86% and the bearing displacement by 96% as compared to non-isolated LSTs. This novel isolation effectively reduces the risk of LST failure under dynamic loads due to its high energy dissipation capacity, effective stiffness, damping, and yield strength, even at low bearing displacements.