Investigation on dynamic performance of soilbag cushion using shaking table tests

Soilbag cushion is one of the promising base isolation methods to reduce seismic energy transfer from ground to building structure. In this study, a series of shaking table tests were conducted comparatively on foundation models with soilbag cushion and sand cushion to evaluate their dynamic performance. The test results indicate that soilbag cushion could significantly reduce acceleration response and accumulated settlement compared to sand cushion. And the relatively smaller amplitude of dynamic lateral earth pressure measured on contact surface of soilbags within soilbag cushion also indicates its stability during oscillation. The advantages of soilbag cushion for energy dissipation and damping are more easily highlighted under the condition of high-acceleration, high-frequency or high uniformly distributed load. The dynamic performance of soilbag cushion is dependent on embedded depth and thickness. It is most effective for soilbag cushion to be arranged near the rigid footing of building structures; it is suggested that the number of layers of soilbag cushion be controlled on the premise of the designed ratio of the thickness to the width of soilbag cushion ranging from 0.125 to 0.4 for low- or middle-rise masonry buildings in practical engineering.