Analysis Of Longitudinal Force Of Ladder Track Sleeper On Bridge In Urban Rail Transit

Ladder sleeper is a new type of track structure. The transfer mechanism of longitudinal forces of the rail equipped with ladder sleepers on bridge is different from that of traditional ballastless track because of structural differences. Currently, however, the research and the application of ladder sleeper remains in its infancy, so the research on longitudinal forces is still few.The research in this thesis is on the basis of the domestic and foreign. In view of the above-mentioned problems, this thesis accomplished the following studies:(1) This thesis explained that there existed some irregularities in analyzing the rail equipped with ladder sleepers on viaducts by using traditional rail and bridge model directly. According to the characteristics of rail equipped with ladder sleeper and urban rail transit bridge, this thesis proposed a practical longitudinal integration analysis model called rail-sleeper-bridge in simple-deck box-girder bridge in urban rail transit, so as for convenience of the analysis of FEA softwares.(2) This thesis has computed the longitudinal forces of each working condition by using the established computation model and design parameters in engineering application, taking 5-span, 30m simple-deck box-girder bridge as an example, and compared the computation result in the most disadvantageous working condition with the traditional ones, and eventually concluded that sleeper, convex retaining platform, elastic support shouldn't be neglected when analyzing the longitudinal force.(3) This thesis has considered the influence of the value of the stiffness of convex retaining platform's cushion, frictional resistance elastic support, fastener resistance on the longitudinal forces, studied the changing rules of the contractility,flexural force,brake resistance,value of breaking joint of continuous welded rail equipped ladder sleeper on urban rail transit viaducts as the influence factors changed, and then explored the reasonable value of parameters on the basis of the changing rules.