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Theoretical and experimental investigations of the dynamic behaviour of ground‐supported, deformable, cylindrical liquid storage tanks were conducted. The study was carried out in three phases: (I) a detailed theoretical treatment of the coupled liquid‐shell system for tanks rigidly anchored to their foundations; (II) an experimental investigation of the dynamic characteristics of full‐scale tanks; and (III) a development of an improved seismic design procedure.

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A method for analyzing the earthquake response of deformable, cylindrical liquid storage tanks is presented. The method is based on superposition of the free lateral vibrational modes obtained by a finite-element approach and a boundary solution technique. The accuracy of such modes has been confirmed by vibration tests of full-scale tanks. Special attention is given to the cos θ-type modes for which there is a single cosine wave of deflection in the circumferential direction. The response of deformable tanks to known ground motions is then compared with that of similar rigid tanks to assess the influence of wall flexibility on their seismic behavior. In addition, detailed numerical examples are presented to illustrate the variation of the seismic response of two different classes of tanks, namely, “tall” and “broad” tanks. Finally, the significance of the cos nθ-type modes in the earthquake response analysis of irregular tanks is briefly discussed.

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SUMMARYAn innovative method of analysis was developed to simulate the non-linear seismic finite-amplitude liquid sloshing in two-dimensional containers. In view of the irregular and time-varying liquid surface, the method employed a curvilinear mesh system to transform the non-linear sloshing problem from the physical domain with an irregular free-surface boundary into a computational domain in which rectangular grids can be analysed by the finite difference method. Non-linearities associated with both the unknown location of the free surface and the high-order differential terms were considered. The Crank-Nicolson time marching scheme was employed and the resulting finite difference algorithm is unconditionally stable and very lightly damped with respect to the temporal co-ordinate. In order to minimize numerical instability caused by the computational dispersion in spatially discretized surface wave, a second-order dissipation term was added to the system to filter out the spurious high-frequency waves. Sloshing effects and structural response were measured in terms of sloshing amplitude, base shear and overturning moment generated by the hydrodynamic pressure of the liquid exerted on the container walls. Simulation results of liquid sloshing induced by earthquake and harmonic base excitations were compared with those of the linear wave theory and the limitations of the latter in assessing the response of seismically excited liquids were addressed.KEY WORDS: liquid sloshing; nonlinear large-amplitude waves; hydrodynamic pressure; seismic response; numerical stability and dissipation; physical and computational domains

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