Dynamic buckling and seismic fragility of anchored steel tanks by the added mass method

Abstract

SUMMARY Buckling plays a fundamental role in the design of steel tanks because of the small thicknesses of the walls of this class of structures. The first part of the paper presents a review of this phenomenon for liquid‐containing circular cylindrical steel tanks that are fully anchored at the base, considering the different buckling modes and especially the secondary buckling occurring in the top part of the tank. A case study based on a cylindrical tank is then introduced in order to investigate various aspects of dynamic buckling. The finite element model of the case study tank is set‐up using the added mass method for fluid modelling. The influence of pre‐stress states caused by hydrostatic pressure and self‐weight on the natural periods of the structure is first studied and it is found that this influence is very small as far as the global behaviour of the tanks is considered, while it is important for local, shell‐type, vibration modes. In the following, the efficiency and sufficiency of different ground motion intensity measures is analysed by means of cloud analysis with a set of 40 recorded accelerograms. In particular, the peak ground displacement has been found being the most efficient and sufficient intensity measure so far as the maximum relative displacement of the tank walls is concerned. Finally, incremental nonlinear time‐history analyses are performed considering the case study structure under recorded earthquake ground motions in order to identify the critical buckling loads and to derive fragility curves for the buckling limit state. Copyright © 2013 John Wiley & Sons, Ltd.

Seismic Fragility Analysis of Steel Storage Tanks

“…In order to estimate the seismic vulnerability and to derive fragility curves, extensive (buckling) and complete damage states (complete collapse due to the failure of the support system) have been here considered. [17]. An example of both the buckling phenomena is illustrated in Figure 1.…”

Liquid-containment shells of revolution: A review of recent studies on strength, stability and dynamics

“…For such tanks, static buckling models provide a reasonable approximation of the buckling strength of the shell under wind. Very recently, and adopting the added-mass technique to dynamically account for the presence of liquid in the tank, Buratti and Tavano [45] have investigated critical buckling loads of cylindrical steel tanks that are fully anchored at the base and experiencing earthquake-induced ground motions, and obtained seismic fragility curves for these.…”

An efficient computational procedure for the dynamic analysis of liquid storage tanks

“…The study of the dynamic behavior on liquid storage tanks has gained significant attention in the last years as the seismic vulnerability of these tanks represents a potential source of significant economic loss due to structural failures, leakages or environmental accidents (caused by the liquid spilled out) [1][2][3], whereas such tanks have been proposed to be used as mass dampers to mitigate the vibration induced by wind or seismic excitations [4]. Several approaches have been proposed in this setting to model the dynamical behavior of such liquid storage tanks.…”