Influence of Soil-Pile-Structure Interaction on Seismic Response of Long Span Suspension Bridge

For obtaining the accurate dynamics behavior of a suspension bridge, the Lancangjiang River Bridge is taken as an example, which is a suspension bridge with steel concrete composite stiffening girders. The spatial dynamic FE model is established and a soil-pile-structure interaction is simulated using the lumped-mass model of single-pile by modifying the Penzien J model. Then a 3-dimensional nonlinear time history analysis for the bridge is investigated by the nonlinear dynamic analysis method of inconsistent excitations established based on Large Mass Method and Pseudo-Static Displacement Conception. Analytical results show that the effects of soil-pile-structure interaction on dynamic characteristics of a long-span suspension bridge mainly result in a decrease of structure stiffness and the change of mode order, and that the effects of soil-pile-structure interaction on seismic response of long-span suspension bridges are closely related to the simulation of seismic ground motion and traveling wave effect. It's greatly necessary to utilize a soil-pile-structure interaction model to perform seismic analysis and design even if the stiffness of the pile foundation is ensured.