Seismic response of buildings resting on soil isolated with EPS geofoam buffer

The present study deals with analyzing the efficacy of EPS (Epoxy Polystyrene) geofoam buffer as a soil-isolation medium to reduce the seismic energy transferred and, thereby to reduce the dynamic response of buildings under earthquake induced loads. Finite element simulation of the transient response of an integrated soil isolation-building system in which, buildings resting on raft foundation in medium dense sand beds, with and without soil-isolation mechanism has been carried out using a recorded accelerogram of El Centro earthquake. Four sets of three-dimensional buildings (one, two, three and four-storey) of single bay moment resisting concrete frames have been considered for the analysis. The EPS geofoam buffer of various thicknesses was placed at different depths below the raft foundation. The results under field-scale conditions indicate that soil isolation provided by the EPS geofoam buffer substantially reduces the earthquake energy transmission to the superstructure during a strong earthquake.