Earthquake-resilience of storage tanks: using an innovative anchorage system

Abstract

In this study, a new anchorage system has been introduced by employing the recently developed Resilient Slip Friction Dampers (RSFDs) as ductile self-centring hold-downs for liquid storage tanks. This new anchorage mechanism significantly mitigates the transmitted earthquake force to storage tanks by providing more dynamic flexibility and dissipating the input energy through friction without experiencing any damage in the designed level, contrary to other common ductile yielding hold-downs. The conventional ductile systems such as necked rods include sacrificial elements which experience undesirable damage resulting in strength and stiffness degradation or even failure in severe scenarios. Recently, buckling restrained systems were adopted to control the pinching effect of the necked rods, however resulting is high stress zones in the tank body requiring thickening of wall, not to be cost efficient. In this paper, a new tank seismic anchorage system has been introduced addressing the shortcomings of the current available solutions. Initially, an experimental component testing has been conducted to demonstrate the RSFD performance. Then, a case study of steel cylindrical storage tanks has been investigated comparing the effect of RSFD anchorage system with other ductile concepts (eg, necked-rod and buckling-restrained system). For this purpose, IDA time history analyses have been performed and the findings have been presented based on the average of a collection of seven ground motions.