Dynamic Performance Evaluation of a High-Speed Four-Track Railway Bridge Traversed by Multiple Trains

With the continuous construction of high-speed railway networks in China, long-span railway bridges which carry multiple tracks are being put into service on the high-speed railway line. However, few studies focus on bridge dynamic behavior and train running performance of high-speed railway bridges traversed by multiple trains. Base on a four-track railway bridge, the Nanjing Dashengguan Bridge, the dynamic analysis of the bridge considering the intersection and the parallel of multiple trains is performed using the train-track-bridge dynamic model. Then the acceleration responses of bridge girder and train running parameters are evaluated in the loading cases of multiple trains at different train speeds. The results show, first, that the transverse acceleration responses of the girder depends on the running direction of trains (intersecting or parallel). The maximum transverse acceleration of the two-train parallel case is obviously smaller than that of the single-train case, whereas the maximum transverse acceleration of the two-train intersecting case is greater than that of the single-train case. The maximum transverse acceleration of the three-train and four-train cases is close to the value of the single-train case and the two-train parallel case, respectively. Second, the vertical acceleration responses of the bridge girder depend on the number of running trains. The maximum vertical accelerations of the bridge are approximately in linear proportion to the number of trains running on the bridge. Third, the transverse train running parameters (especially the derailment coefficient and the transverse acceleration of the train car body) are the most detrimental in the two-train intersecting case, and are at a high level in the single-train case. Hence, the two parameters should be controlled in bridge design. The vertical train running parameter (especially the wheel unloading rate) is the most detrimental in the four-train case, and it becomes more significant with the increasing number of running trains. Hence, the wheel unloading rate should be controlled by the reasonable scheduling of running trains.