Study On Longitudinal Dynamic Problem Of Heavy Haul Railway Bridge Considering Shock Transmission Unit

For the past few years, heavy haul railway developed rapidly because of its large transport capacity, high efficiency, and low transportation cost. But the design load in railway bridge design code of our county is low, can’t meet the requirement of heavy axle load. Of all loads which is borne by railway bridge, the braking force acting on rail surface is the main factor of railway live load. The rise of axle load increase the braking force directly, this may induce the break of substructure because the actual braking force beyond the design load. When the structure form of heavy haul railway is simply sup-ported beam, the braking force is only borne by the fixed pier on which the wheel-set effect directly, the ability of bearing force of the bridge can’t be given full play. With the installation of shock transmission unit, for one thing, each span is coupled, share the braking force together, to improve the forced state of bridge; For another, keep the bridge to be a statically determinate structure to avoid the additional force caused by temperature.This paper mainly studies the application of shock transmission unit in railway bridge, contains three aspects:the calculation of the braking force, the longitudinal analysis of Vehicle-Bridge Coupling System, and the application of shock transmission unit in railway bridge. Referring to the application of shock transmission unit in high-way bridge, this paper take the research of longitudinal dynamic response of heavy haul railway bridge considering shock transmission unit, based on shuo-huang railway. The study includes the following aspects:(1) It is summarized the research method of Vehicle-Bridge Coupling System, in-troduce the modeling method of bridge and vehicle, the simulation of wheel-rail rela-tionship, and the solution of Iterative Method. We propose a method about the calcula-tion of braking force which is more realistic.(2) It is studued the response of heavy haul railway such as longitudinal rail stress, longitudinal displacement of rail, and other main dynamic indexes in the effect of brak-ing force. Also study the change law of dynamic indexes under two different braking models.(3)With the considering of working principle and the curve of load of STU based on velocity, It is selected the proper element to simulate STU, build the finite model of Vehicle-Bridge-STU Coupling System and discuss how to determine the parameters. (4) We propose some feasible schemes of the arrangement of STU, and compare the response of the bridge between different schemes to determine which scheme is best. Take the research of the affect to the mechanical behavior of the heavy haul railway bridge when the STU is broken.