The effect of earthquake frequency content on the seismic behavior of concrete rectangular liquid tanks using the finite element method incorporating soil–structure interaction

A three-dimensional soil–structure–liquid interaction is numerically simulated using the finite element method in order to analyze the seismic behavior of partially filled concrete rectangular tanks subjected to different ground motions. In this paper, the effect of earthquake frequency content on the seismic behavior of fluid rectangular tank system is investigated using four different seismic motions. A simple model with viscous boundary is used to include deformable foundation effects as a linear elastic medium. This method is capable of considering both impulsive and convective responses of liquid-tank system. Six different soil types defined in the well-recognized seismic codes are considered. The sloshing behavior is simulated using linear free surface boundary condition. Two different finite element models corresponding with flexible shallow and tall tank configurations are studied under the effects of longitudinal, transversal and vertical ground motions. By means of changing the soil properties, comparisons are made on base shear, base moment and sloshing responses under different ground motions. It is concluded that the dynamic behavior of the fluid–tank–soil system is highly sensitive to frequency characteristics of the earthquake record.