Research on the seismic responses of frame construction on sand-gravel cushion

The main purpose of this paper was to study what impact the sand-gravel cushion may make on seismic responses of frame construction on it. This paper uses a reinforced concrete frame construction on the sand-gravel cushion as the analytical model, and two calculating models were made in finite element method for it, one is the reinforced concrete frame construction with sand-gravel cushion under it, the other is the same superstructure but with rigid foundation. The seismic responses of the 2 calculating models were calculated in time history method. By comparing the seismic responses of the reinforced concrete frame structure on sand-gravel cushion and the seismic responses with rigid foundation, it was found that with sand-gravel cushion under the constructions, the displacement of the construction at the bottom of the structure increased a little while the displacements of the other floors all decreased, and the acceleration responses of the constructions on sand-gravel cushion all decreased comparing to the construction without sand-gravel cushion. As the results show, the sand-gravel cushion served as a vibrating isolation in a certain extent, that the seismic displacement and acceleration responses of the constructions on it all decreased.