EFFECT OF FOUNDATION DEPTH ON SEISMIC RESPONSE OF CABLE-STAYED BRIDGES BY CONSIDERING SOIL STRUCTURE INTERACTION

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 popularity and numbers are increasing nowadays because of economical longer span &aesthetic good look. The current paper examines the effect of depth of foundation on seismic response of cable-stayed bridges. In total 16 cases are solved with and without SSI by time-history analysis with Finite Element Program. Full 3D bridge model is developed and soil is modeled 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 a great role in seismic response of the bridge; the medium depth foundation is proven critical compared to other cases.