Force Analysis of CRTS II Slab Track on Long Span Bridge under Damage Conditions

The mileage of longitudinal continuous slab track in China has exceeded 5,000 km. It is composed by multilayer track structures and many components. The interaction between long span bridge and continuous slab track structure is rather complex. To research the force distribution of the continuous slab track on the long span bridge. Basing on the theory of the bridge and rail interaction, a finite element model including the space system of rail-track plate-base plate-beam-pier is established and verified. Taking a typical long span bridge as the engineering example. The temperature model which considers the temperature gradient is based on the long-term measured data. Different damage conditions of sliding layer, track plate expansion stiffness, and plate fracture are respectively simulated to analyse the performance of the track system. The results show that the beam end rotation caused by temperature gradient and vertical load would has big effect on the rail stress of continuous slab track, the bending additional stress should be considered with the expansion additional stress when the rail stress is needed to be checked. The rail additional stress and longitudinal forces of connecting components increase with the sliding friction coefficient. Meanwhile, the cracking condition of the concrete plate will cause significant increase in the rail stress. Both the maximum sliding friction coefficient of sliding layer and cracking condition of concrete plate should be considered to decide the arrangements of connecting components and the ultimate expansion span of the bridge. In addition, the plate fracture will lead to a negative effect on the track structure. The rail additional stress at the fracture position will exceed the limited value in the specification and the shear steel bars there will be cut off. It is suggested that the number and strength of the shear steel-bars at the position where the fracture is most likely to happen should be increased.