A new approach to soil-pile-structure modeling of long-span bridges subjected to spatially varying earthquake ground motion

摘要

This paper presents a study about the spatial variability effects of ground motion and Soil-Pile-Structure Interaction (SPSI) on the dynamic response of a long bridge. The Spatially Varying Earthquake Ground Motion (SVEGM) is simulated by SIMQKE-II record generator. Target response spectrum and power spectral density function used in the simulation are determined depending on the January 17, 1994, Northridge earthquake. To evaluate the effect of SPSI, the soil surrounding the pile foundation is modelled by frequency- independent springs and dashpots in the horizontal and rotational directions. The effect of soil-pile mass is considered by lumped-mass soil-pile model. A new analytical model is proposed to study the effect of both SVEGM and SPSI on dynamic response of long bridges. The study reveals that the effect of both SVEGM and SPSI in the dynamic analysis and design should be considered simultaneously. A comparison between the results, based on the new suggested model and those given for other similar studies shows that the model could be applicable in calculation of dynamic response of long bridges. Considering the effect of soil-pile contributed mass along with the stiffness and damping is result in applying a model similar to a real soil-pile-structure system. It can simulate the real dynamic behavior of substructure more exactly.