Effect of Longitudinal Resistance of Line on Seismic Response of Bridge-track-catenary System
Research purposes:To investigate the seismic response characteristics of the bridge-track-catenary system under different longitudinal resistances,a sophisticated simulation model was established,taking the example of a 7×32 m double-track simply supported box girder installation.The influence of longitudinal resistance on the seismic response of each component in the system was explored,the response characteristics of different components under various seismic waves were analyzed,and the impact of the catenary structure on the track-bridge system was also revealed.Research conclusions:(1)The longitudinal resistance significantly affected the stress on steel rails and the longitudinal deformation of fasteners.Moreover,the implementation of a ballastless track system notably reduced the deformation of fasteners at the piers while increasing the stress on rails at both ends of the bridge piers.Under the action of El-Centro seismic wave,the longitudinal deformation of fasteners under longitudinal resistance of ballastless rail fasteners is 16.7%and 15.0%lower than that under ballasted track and small resistance fasteners respectively.(2)The seismic response of the catenary structure and the bridge structure showed minor sensitivity to longitudinal resistance.(3)Under different longitudinal resistances,the impact of El-Centro wave on the bridge structure and track structure was greater than that of the Taft wave.Specifically,under the El-Centro seismic wave,the bridge stress was 9.6%higher for smaller fastenings and 7.4%higher for the ballast track compared to the ballastless track.(4)The presence of the catenary structure influenced the overall stiffness of the system.Considering the catenary,the bridge stress and the bottom shear force of the bridge piers significantly increased.It is recommended that during the design of high-speed railway bridges in seismic regions,the influence of the catenary structure should be taken into account.(5)The research results can provide reference for the seismic design of the track structure on the bridge.
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