High-iron Medium And Small Span Continuous Beam Bridge Rail Interaction Research

The interaction between the beam and track of high-speed railway bridge is the key technology to ensure the smooth running of high-speed trains. Hence, the main purposes of studying the interaction are to determine the longitudinal force carried by the pier to ensure the security and stability of track, and limit the relative displacement caused by braking force between the beam and track to ensure integrity of ballast bed. At present, the existing researches on interaction have mainly focused on the small span simply-supported bridges, while there is not so much works on continuous bridges. In this thesis, based on the construction project (High-Speed Railway from Xiamen to Shenzhen), the main works contains as follows:1. A overall finite element model was established through the ideal elastic-plastic mechanical model of longitudinal resistance, which can calculate the additional forces leaded by the braking, track expansion and beam deflection.2. Based on the analysis of XianShuiXi long continuous beam bridge (9-32m beam +6x32m continuous beam) with ballasted track, the additional longitudinal stress of rail, the additional longitudinal stress of rail and the relative displacement caused by braking force were studied. Meanwhile, taking the longitudinal resistance and the longitudinal stiffness of the pier as parameters, the effect on the interaction between beam and track were studied.3. Taking the bridge (9-32m beam+6x32m continuous beam) as an example, The basic law of the interaction between beam and track and the basic feature of the relative displacement caused by braking force are investigated, for continuous beam without ballast. Then, the main factors which affect the interaction between beam and track, longitudinal resistance and longitudinal stiffness of pier are studied.4. A comparative study of the similarities and differences between the ballasted track and ballastless track continuous bridge is finally carried out on the aspect of the interaction force and relative displacement. It is shown that the ballasted track is superior to the ballastless track in terms of the interaction force, but inferior in relative displacement.