Effect of Foundation Depth on Seismic Response of the Cable-stayed Bridge by Considering of Soil Structure Interaction

Abstract

Post failure analysis of massive structure infers that Soil-structure interaction (SSI) is a crucial phenomena influencing seismic response of massive structures. Cable-stayed bridge's popularity and numbers are increasing now-a-days because of economical longer span & aesthetic good look. The current paper examines the effect of depth of foundation on seismic response of cable-stayed bridge. Total 16 cases are solved with and without SSI by time history analysis with the Finite Element Program. Full 3D bridge model is developed and soil is model by assigning the spring and dashpots as Kelvin element to simulate SSI effects. The result yielded that SSI effects must be considered for soft soil conditions irrespective of the depth of foundation. The effects of SSI are site specific and cannot be generalized. However the fundamental time period is increasing as high as 28% due to SSI effects. The depth of foundation has also great role in seismic response of bridge; the medium depth foundation is proven critical compare to other cases.