Shaking table tests of a full-scale base-isolated flat-bottom steel silo equipped with curved surface slider bearings

This paper presents a series of shaking table tests on a full-scale flat-bottom steel silo filled with soft wheat, under isolated-base conditions. The tested specimen is a 3.64 m-diameter 5.50 m-height corrugated-wall cylindrical silo, representing the smallest manufactured silo available in the catalogue of an Italian commercial silo provider. Curved Surface Slider isolators were introduced between the shaking table and the reinforced-concrete plate, on which the silo was mounted, to realize the isolated configuration where the main results have been investigated and compared with other results for the same silo specimen under fixed-base conditions. A detailed description of the silo components, the filling bulk material properties as well as the test setup is provided, including the full testing protocol. Multiple sensors were used to monitor the dynamic response of the filled silo system, including accelerometers, pressure cells, LVDT displacement transducers. Numerous unidirectional dynamic tests were conducted consisting of random signals, sinusoidal inputs, pulse-like inputs, and both artificial and real earthquake records. The results were processed to evaluate the performance of the isolators and their effectiveness on the silo response in terms of measured accelerations and dynamic overpressures. The efficiency of the isolation on the reduction of both acceleration amplifications over the silo wall height as well as the captured dynamic overpressures were detected in the range 30%–80% depending on the input type and magnitude.