Effect of pier temperature gradient on longitudinal force of CRTS Ⅱ slab ballastless track on bridge

For the longitudinal additional force and deformation of China railway track system (CRTS) Ⅱ slab ballastaless track on bridge caused by the pier temperature gradient, the spatial coupling models of CRTS Ⅱ slab ballastless track continuous welded rails (CWR) on the multi-span simply supported beam bridge and long-span continuous beam bridge were established by using the finite element method based on the beam-slab-rail interacting principle. Both the dimensions and mechanical properties of main and detail structures, such as rail, track slab, cement asphalt (CA) mortar, base plate and bridge, were considered in detail. The longitudinal displacement of pier top caused by the action of longitudinal temperature difference of pier was calculated by the unit load method, to analyze the distribution rules of longitudinal force and displacement of ballastless CWR on the bridge under the influence of displacement of pier top. Analysis result shows that when the uniform displacement of each pier top occurs, the distribution laws and the maximum values of longitudinal force of ballastless track CWR on the multi-span simply supported beam bridge and long-span continuous beam bridge are basically the same, and increase linearly with the increase of uniform displacement of pier top. The peak relative displacement between the rail and track slab appears at the ends of abutment on both sides, the anchorage structures behind the abutments, tops of the second and last spans fixed support piers. When the uniform displacement of pier top is 5 mm, the maximum longitudinal forces of rails on the multi-span simply supported beam bridge and long-span continuous beam bridge are 79.62 and 79.54 kN, respectively, the maximum longitudinal displacements are 4.94 and 4.91 mm, respectively, and the maximum relative displacement between the rail and track slab is 0.23 mm. When the uneven displacement occurs at the top of each pier, the longitudinal force of rail and the relative displacement between the rail and track slab change abruptly at the displacement difference between adjacent piers. The longitudinal force of consolidation mechanism on the multi-span simply supported beam bridge is greater than that of long-span continuous beam bridge. For high pier bridges, it is necessary to pay more attention to the relative displacement between the rail and track slab at the maximum height difference between adjacent piers, the relative displacement between the base plate and bridge and the longitudinal force of consolidation mechanism. © 2020, Editorial Department of Journal of Traffic and Transportation Engineering. All right reserved.