Numerical Modelling of the Dynamic Response of High-Speed Railway Bridges Considering Vehicle-Structure and Structure-Soil-Structure Interaction

The aim of this paper is the dynamic analysis of a multi-support bridge structure exposed to high-speed railway traffic. The proposed computational model has a unified approach for simultaneously accounting for the bridge structure response, soil response and forces induced by the vehicle. The bridge structure is modelled in three dimensions based on the finite element method using two-noded three-dimensional beam elements. The track structure is composed of three layers: rail, sleepers and deck which are connected through spring-dashpot systems. The vehicle travelling along a bridge is idealized as a multi-degree-of-freedom system, modelled with two layers of spring-dashpot suspension systems. Coupling the vehicle system and railway track is realized through interaction forces between the wheels and the rail, where the irregularities of the track are implemented as a random stationary stochastic process. The soil body is considered as a layered half-space employing the transfer-matrix methods to obtain the Green's functions in the frequency domain. An iteration procedure is proposed for simultaneously solving the time-domain solution of the multi-degree-of-freedom vehicle affected by the bridge displacements and track unevenness together with the frequency-domain solution of the bridge structure coupled with the subsoil. The effects caused by different soil properties and stratification, as well as different vehicle speeds are determined and compared.