Lid induced sloshing suppression and evaluation of wall stresses in a liquid storage tank including seismic soil‐structure interaction

Abstract

AbstractAboveground liquid storage tanks are often found on weak compressive soil due to their proximity to harbours and rivers. These soil conditions lead to a high probability of significant soil‐structure interaction (SSI) under earthquake loading. In strong earthquakes, the transient partial separation of the tank base from the supporting medium (uplift) and chaotic liquid sloshing often cause damage to the tank wall. This experimental research determines the simultaneous effects of SSI and the restriction of sloshing on the development of hoop and axial stresses in the tank wall. A low‐density polyethylene tank with two different supporting foundation conditions, that is rigid and flexible, was tested using a shake table. A high‐density foam floating lid was utilised as a barrier to the development of sloshing enabling evaluation of the contribution of sloshing to wall stress development. The maximum experimentally determined stresses are compared with those from a nonlinear elastic spring‐mass model. The results reveal that a flexible supporting medium reduces the development of stresses by increasing the occurrence of uplift compared to that when the tank lies on a rigid supporting medium. Furthermore, restricting chaotic sloshing decreases both the maximum stress and uplift. The spring‐mass model predicts the maximum stresses with more accuracy when the tank is on a flexible than on a rigid supporting medium.