The effect of foundation-soil-foundation interaction on the response of continuous, multi-span railway bridges

This paper focuses on the effect of dynamic soil-structure interaction (SSI), including foundation-soil- foundation interaction (FSFI), on the dynamic response of multi-span railway bridges, which constitute an important part of high-speed rail networks around the world. We consider an infinitely long box girder bridge on piled foundations and use periodic structure theory to restrict the computational domain to a reference cell. The superstructure is modeled with finite elements, while a periodic finite element-boundary element (FE-BE) model is used to compute the dynamic stiffness of the piled foundation, taking into account FSFI. It is demonstrated that (1) the natural frequencies of the in-phase torsional and bending modes are significantly lowered due to the flexibility of the foundation-soil system; (2) the effect of FSFI on the bridge response is limited for typical span lengths and soil stiffness; and (3) the peak bridge deck acceleration is lower if SSI is taken into account, as is the resonant train speed.

Automated summary

This paper investigates the impact of dynamic soil-structure interaction (SSI), including foundation-soil- foundation interaction (FSFI), on the dynamic response of multi-span railway bridges. The findings show that considering SSI can reduce the peak bridge deck acceleration and resonant train speed.