Dynamic responses of railway bridges subjected to floating-ice collision and their influences on running safety of high-speed trains

摘要

The impact of collision loads such as floating-ice on piers may induce the vibration of bridge superstructure, which may further influence the safety of train vehicles running on the bridge. This problem should be noticed in design of bridges in cold regions, especially for high-speed railway bridges. To analyze the dynamic responses of railway bridges subjected to floating-ice collision and their influences on the running safety of high-speed trains, a dynamic interaction analysis model for a train-bridge system subjected to collision-load of drifting-ice is established. The model consists of the collision load, the train subsystem model, the bridge subsystem model, and the track irregularity model. The collision load time history curve of floating-ice is obtained via site experiment at the Jiamusi Songhua River Bridge, and is applied at the bridge piers in transient style. By taking a continuous beam bridge with the span of 48+80+48m as the case study, the whole histories of a train running on the bridge are simulated when the floating ice sheet strikes on the bridge piers, from which the dynamic responses such as displacements and accelerations of the bridge, and the running safety indices such as derailment coefficients, offload factors and lateral wheel-rail forces of the train vehicles are obtained. The numerical results show that the collision of floating ice has obvious effect on the dynamic responses of the bridge and the train vehicle. The displacement and acceleration responses of the bridge and the running safety coefficients of train vehicles increase with train speed. Some running safety indices of train vehicle exceed the corresponding allowances in the Chinese Code. The ice collision load should be treated as one of the important factors to be considered in design of high-speed railway bridges in cold-temperature zones.