Shaking table tests of a base isolated steel liquid storage tank

The paper deals with the results of shaking table tests upon a steel liquid storage tank with a 4 m diameter filled with water up to one meter. This thank is a 1:14 scale model of a real big liquid steel storage tank installed in a petrochemical plant. First, the tank has been tested in fixed base configuration simulating the presence of the floating roof as well. Subsequently, the same thank has been seismically protected with two type of isolators: high damping rubber bearings and sliding isolators equipped with elastoplastic dampers. In each configuration the model has been subjected to the same series of tests. The results confirm the negligible influence of the floating roof and the effectiveness of both the isolation systems in order to reduce the pressure on the tank wall, and as well. On the contrary, in the isolated case a light increasing of the vertical oscillations of the floating roof has been found, partially compensated by a significant increasing of the damping, which reduce the number of the free oscillation in the post-earthquake phase.