Influence of anchoring on the seismic fragility of buckling in liquid storage tanks considering soil-tank interaction: a case study for wine storage tanks

Abstract

In the last decades, numerous liquid storage tanks have been affected by strong earthquakes, the damage observed ranges from the partial collapse to the total collapse of the storage tanks. Elephant-foot buckling is one of the most common failures observed in these structures, which can provoke their collapse and complete loss of contents. While hydrostatic and hydrodynamic loads typically impact the seismic response of tanks, the soil type on which they are built plays an important role in influencing their performance during earthquakes. However, the soil-tank interaction has not been considered in the seismic fragility analyses of continuously supported tanks. This research aims to evaluate the seismic fragility of a continuously supported wine storage tank with a particular focus on elephant-foot buckling considering the soil-tank interaction. A specific soil condition and a typical wine storage tank are evaluated utilizing pushover-based seismic analysis and the Capacity Spectrum Method (CSM). 3D nonlinear Finite Element (FE) models are developed considering the tank, foundation, and soil. Seven ground motion records compatible with the soil type are considered. The seismic fragility is estimated using the FE models and the ground motion records. Both unanchored and anchored conditions are evaluated. The obtained results show that for the considered case study, the anchored condition shows better seismic performance when compared to the unanchored condition.