Effects of Earthquake Vertical Excitations on Sloshing Height in Conic Elevated Water Tanks and the Created Moment at Their Base: Experimental Validation and Numerical Simulation

In seismic analysis, vertical component of the earthquake due to the impact on fluid sloshing in a tank and intensifying of "P-delta" effects is of particular importance. In order to investigate the performance of the tank and the impact of the fluid surface sloshing, harmonic frequencies were applied to a tank of of water with 60 cm in diameter and different depths of water. Different frequencies were applied to the tank by an innovative tool. Abacous is a structural soft-ware which is capable to model numerically the interaction of structure and fluid. Verification and calibration of numerical model was performed by comparing water level fluctuations in experimental and numerical models. Different combinations of parameters such as hourglass coefficient, methods of grid generations and the cell sizes in numerical model were performed to obtain the consistent results with experiments. The results of numerical modeling had a correlation factor of 98% with laboratory results. Then, the numerical model of elevated tanks with large scales were created in software The numerical model of elevated tanks with three different ratios of fluid depth and tank radiuses to the tank height were created and modeled by software. The angle of the floor in all tanks was 45 degrees. Each case was evaluated by7 different mapping acceleration from different earthquakes. In all cases the effect of vertical component of earthquake, the wave height and moment in foundation were investigated. The results showed that the vertical component of the earthquake resulted in an increase of 38% in the height of water and 9% increase in the moment of foundation.