Vibration Studies of a Coupled Tank-Block-Isolation System Using a Lead Rubber Bearing Isolator

Abstract

The present study attempts to examine the influence of an internal submerged block on the overall dynamic behavior of a coupled tank-block-isolation system using a lead rubber bearing isolator. A partially filled rectangular liquid tank with a bottom-mounted block is modeled using a velocity potential-based Galerkin finite element method and subjected to a harmonic ground excitation. The competency of the developed model is verified with the existing results. The peak values of the hydrodynamic responses for base-isolated and non-isolated tanks are evaluated for different heights and widths of the submerged block, where the effect of changing height is found to be more significant than the varying width. The application of lead rubber bearing is found to be effective in controlling seismic responses such as hydrodynamic pressure, base shear, and sloshing amplitudes. The fundamental sloshing frequency for different configurations of the non-isolated tank is evaluated from the free vibration analysis. However, for the base-isolated tank configurations, it is obtained by an indirect method of forced vibration analysis under the harmonic excitation in a frequency domain. Also, resonance studies are performed for the specified configuration of both tank systems to differentiate the critical responses under different resonant frequencies.