Mechanical Properties of CRTS Ⅱ Slab Ballastless Track on Bridge under Temperature Gradient Loads

In order to study the influence of transverse and vertical temperature gradients on the longitudinal mechanical performance of CRTSⅡ slab ballastless track on the bridge, on the basis of the beam-slab-rail interaction principle, a refined spatial finite element model is established for the continuous welded rails (CWRs) of CRTSⅡ slab ballastless track on the long-span bridge. The longitudinal force and displacement of rails and bridge structure on southern and northern surfaces are calculated under the transverse and vertical temperature gradient loads. Analysis results indicate that the vertical temperature gradient of the track slab has little effect on the longitudinal force and displacement of the rail under the same temperature load. When the transverse temperature difference between the southern and northern surface is 10 ℃, the maximum longitudinal force of the rail at the northern side of the continuous beam is 1.4 times that at the southern side, and the maximum longitudinal force of the pier at the northern side of the continuous beam is 3.5 times that at the southern side. Under the action of the transverse temperature gradient, the longitudinal force of the rail is generated by the combined effect of beam dilation and torsion d eformations. The greater transverse temperature gradient leads to the greater maximum longitudinal force and displacement of the rail at the northern side, and the smaller maximum longitudinal force and displacement of the rail at the southern side. The transverse and vertical temperature gradient do no contribute to the safe use of the track and bridge structure. Therefore, in the area of high temperature difference, it is necessary to focus on the stress of the rail, track slab and bridge pier top when designing the east-west of CWRs on long-span bridge, and ensure the transverse stability of the CWR on the bridge.