Research on the Dynamic Behavior of “Building-Bridge Integrated” Railway Bridge-Type Station with Setting the Structural Joints on the Mainline

The prevalence of “building-bridge integrated” structures in station design is increasing. However, in stations where the mainline speed exceeds 160 km/h, structural joints are typically incorporated to ensure the integrity and functionality of the integrated system. The inspection and maintenance of these joints, which are critical for the long-term performance of such structures, can be particularly complex. Therefore, it is important to explore the feasibility of designing such stations without structural joints on the mainline. To address this issue, two six-line railway bridge-type stations are selected. The vibration simulation analysis model of the train-track-station coupling system is established, considering two structural types of the “building-bridge integrated” system: the arrival-departure line “building-bridge integrated” and the mainline “building-bridge integrated”. The vibration responses induced by trains passing through two types of “building-bridge integrated” station structures at speeds of 200~350 km/h on the mainline and 80 km/h on the arrival and departure tracks were simulated. The six-line operating conditions were selected as an example, and the influence of setting a structural joint on the mainline on the dynamic response of the “building-bridge integrated” station structure was analyzed. For both types of “building-bridge integrated” station structures, with and without a structural joint on the mainline, the dynamic responses of trains under operational loads show minimal differences. However, the structural joints on the mainline reduce the overall stiffness of the rail bearing floor slab and effectively isolate the train-induced responses transmitted to the platform slab during high-speed operation on the mainline. Therefore, the acceleration response of the platform slab is smaller in station structures with structural joints, while the acceleration and displacement response of the rail bearing floor slab is larger. Additionally, structural joints often lead to issues such as water leakage and seepage. Considering these factors, it is advisable to avoid setting structural joints on the mainline for such station structures.