Abstract
This study experimentally investigates contribution of content liquid to the uplift commencement condition of flat-bottom cylindrical shell tanks subjected to the horizontal base excitation. The conventional analytical models assume that the tank bottom plate uplifts when the overturning moment overcomes the resistant moment consisting of dead weight of a side shell (including the fixed roof and the appurtenances). In other words, the conventional uplifting resistance system in tanks does not implicitly expect any contribution of the content liquid to it.
In this study, a tank model made of PVC was set on a shaking table and the required horizontal acceleration to commence uplift of the tank bottom plate was investigated by increasing the amplitude of the horizontal sinusoidal base excitation step by step. In this experiment, several aspect ratios (Liquid depth / Diameter = 0.25, 0.30, 0.35, 0.40) of the content liquid, which were adjusted by changing the liquid depth, were used. Despite aspect ratio of tanks, the observed acceleration required to commence uplift was larger than that estimated from the conventional analytical model. These results imply existence of the content liquid contributing to the uplift commencement condition of the liquid storage tanks and necessity of its quantification.
