Study on the Influence of Bridge Expansion Joints on Vehicle-Track- Bridge System

Bridge expansion joints (BEJs) are equipped at the girder end of long-span railway bridges to ensure the reliable transition of the track. The track structure of BEJs is more complex than that of bridge, so the BEJs should have suitable dynamic stiffness to ensure the safety and stability of vehicle. Taking a high-speed railway bridge equipped with densely arranged BEJs as an example, a vehicle- track-bridge coupled model was established to analyse the influence of vertical stiffness of BEJs on the dynamic response of whole system. Base on the established model, the study shows that the deformation of the BEJs will cause the short-wave irregularity of the rail and high-frequency impact on the vehicle. The unreasonable stiffness of BEJs will greatly increase the derail risk of the vehicle, so the influence of the stiffness of BEJs on the dynamic response of vehicle should be considered adequately in the design of the BEJs. According to the research results, it is recommended to use a larger stiffness of cushion plate. The results have been applied to the design of the BEJs on the studied railway lines, which are in good service condition at present.