Attaining Optimum Passive Control in Liquid-Storage Tank by Using Multiple Vertical Baffles

Abstract

The effect of vertical baffles as the passive control in liquid storage tanks (LSTs) on the reduction of seismic responses was investigated for bidirectional earthquake excitations. Various baffle configurations were considered for arriving at an optimum coupled arrangement of baffles in the LSTs. For this optimum arrangement of baffles, the change in various responses was studied for several parameters, namely the type, peak ground acceleration (PGA), and angle of incidence of earthquakes. A numerical study was conducted with two flexible concrete LSTs with dimensions 6×6×4.8 and 12×6×4.8 m, and with a water level of 3.6 m in both LSTs. The responses included the maximum percentage change in base shear, overturning moment, top-board displacement, hydrodynamic pressure, and sloshing height. The results of the study showed that (1) with the optimum arrangement of baffles, a reduction on the order of 70% can be achieved in the sloshing height, (2) the type of earthquake does have some significant effect on response reductions, and (3) both PGA and angle of incidence of earthquakes have moderate effects on response reductions.