Effect of vertical acceleration on response of concrete rectangular liquid storage tanks

In this study, the response of concrete rectangular liquid storage tanks subjected to vertical ground acceleration is investigated. The importance of the vertical component of ground acceleration on the overall seismic behaviour of liquid storage tanks is evaluated. The combination of added mass and sequential method is proposed in which the flexibility of the tank wall is considered in the dynamic analysis. The time history response of the tank wall associated with the hydrodynamic pressure distribution is presented. Results show that the time history responses of liquid storage tanks by considering the flexibility of the tank wall in the calculation of hydrodynamic pressures are different from those obtained using the rigid wall assumption. The horizontal response of the tank under the assumed rigid wall boundary condition is more significant than that when wall flexibility is considered. It is concluded that the response of the tank wall due to vertical ground acceleration should be considered in the design.