Braking Forces and Displacements of Longitudinally Counpled Ballastless Welded Turnout on Bridges

A finite element model of turnout-track slab-bridge beam-pier was established to analyze the forces exerted on ballastless track and welded turnout on bridge and their displacements under braking forces, in which a single crossover (composed of 2 sets of No.18 welded turnouts）, the longitudinally coupled ballastless track, the bridge beam and the pier are regarded as one system.The welded turnout of longitudinally coupled ballastless track on Leida bridge on Wuhan-Guangzhou high speed passenger line was taken as an example. Calculation results show that braking forces on and displacement of the stock rail increase with a decrease in the slab stiffness, and the displacement between the slab and the rail is less than 1 mm. The structure of the ballastless track has a little effect on the longitudinal forces exerted on the position-limited devices and spacers, and the displacements of nose rail and switch rail. Braking forces do not result in contact between the two blocks of the position-limited device, and the forces exerted on them are less than 13 kN. A decrease in slab stiffness reduces the forces exerted on it, with a maximum value of 3 832.9 kN, and increases its displacement, with a maximum value of 17.4 mm. Decreasing slab stiffness and friction coefficient of slip layers increases the forces exerted on the piers, and when the friction coefficient is less than 0.2, the longitudinal forces exerted on the piers decreases by about 500 kN.