Research On Initial Deformation Limit Index For Long-span Passenger Dedicated Railway Ballastless Track Bridge

Passenger dedicated railways are being built on a large scale in China nowadays, and the ballastless track tends to be fully adopted with the development of high speed railway, thus, the deformation of the passenger dedicated railway bridge must be strictly controlled with respect to the utilization of ballastless track. It is the critical problem, that bridge deck deformation should be controlled strictly to meet the requirements of running safty and ride comfort of the high speed train. In this paper, the finit elemet models are established respectively for two passenger dedicated railway continuous ballastless bridges with spans of 40+64+40m and 80+128+80m, by which the natural vibration characteristics of the bridges are analysed, and the first 20 modal frequencies and mode shapes are extracted. Subsequently, as additional track irregularity, the creep camber, which were measured on real bridges and statistically analysed, are superposed with the track irregularity generated from the German low-interference PSD, and work as the internal excitation of the vehicle-bridge system. Then the dynamic responses of vehicles and bridges are calculated under the German ICE high speed train running on the bridges, and the influences of train speed and deformation amplitude on the responses of vehicles and bridges are analysed, based on which the deformation limit indexes and train speed thresholds with respect to the train running safty and ride comfort are proposed as a reference of design.