Earthquake induced Sloshing in Tanks with Insufficient Freeboard

Earthquake induced sloshing in tanks is caused by long-period ground motions which attenuate slowly with distance. A minimum freeboard is needed to accommodate the sloshing waves. Since freeboard results in unused storage capacity, many tanks lack the required freeboard. As a result, sloshing waves impact the roof, generating additional forces on the roof and tank wall. Tanks have suffered extensive damage due to sloshing waves, but the effect of sloshing waves is usually ignored in seismic design of tanks. This paper presents a simple method of estimating sloshing loads in cone and dome roof tanks.