The Rail-girder Longitudinal Interaction Studies Of The Rail-cum-Road Cable-stayed Steel Truss Bridge

With the development of the urban rail transport in China and the increasing demand on the landscape and practicality of the bridge, the large span rail-cum-road Cable-stayed steel truss bridge will be adopted in many cases. At present, there are scarce relevant norms and project examples on paving non-ballasted track on the orthotropic plate of the rail-cum-road steel truss bridge, the theoretical reserve and engineering application experience is also inadequate. Through the analysis of the structural characteristic of the rail-cum-road steel truss bridge, combining with the design situation of the non-ballasted track of the rail-cum-road steel truss bridge, this paper analyzes the details of rail-girder longitudinal interaction of the continuously welded rails(CWR) bridge.With the help of the international finite element software ANSYS, spatial integrative mechanical model of rail-girder interaction of Hongyancun Jialing River Bridge in Chongqing was constructed. Nonlinear spring was used to simulate longitudinal resistance and detailed stress analysis was made according to contractile force, braking force, bending force and so on. As for this bridge, its changes of longitudinal additional stress of the steel rail and its rail-girder relative displacement show certain rules under different boundary conditions and longitudinal resistance. The comparative analysis shows that:(1)The role of telescopic adjustment only have a greater impact on the additional longitudinal stress of rail under the temperature force, while the flexural force, braking force, additional stress of rail under moving loads is very small;(2)Since the additional longitudinal stress of rail under flexural braking force is relatively small, when comparing the longitudinal resistance of non-ballasted track line and small resistance fasteners line, the difference between the two is not obvious;(3)When constraining the freedom along the longitudinal direction of bridge at the bearings at both ends of the bridge, no matter under what kind of loads, the additional longitudinal stress of rail on the left side of the rail bridge is relatively small, while the additional longitudinal stress of rail on the right side of the rail bridge is more significant, which is mainly decided by the different boundary conditions on both sides of bridge.(4) With its large span of steel truss bridge, temperature change and highway moving load have great influence on Hongyancun Jialing River Bridge. Therefore, without steel rail temperature controller, rail-girder interaction force will be so great that it is beyond limiting value of additional force. However, this problem can be solved by adopting small resistance fasteners and installing steel rail temperature controllers at25m away from the sides of bridge.