Research On Track-bridge Interaction Of Cable-stayed Bridge Considering Influence Of The Shrinkage And Creep

Track-bridge interaction is one of the dominated factors in the design process for bridges, on which the continuously welded rails are selected and laid. The interaction between track and girder not only has a significant impact on the security of the railway, but also make a great effect on the force condition of the abutments and piers. Up to now, the existing researches on track-bridge interaction have been mainly focused on the small span simply-supported bridges or middle span continuous bridges, while relative works on special form bridges are little and the influence of the shrinkage and creep brought by concrete are almost not considered.Based on a long-span U-shape single pylon cable-stayed bridge on the Shanghai-Kunming high-speed railway,40-32m simply-supported T-shape beams+(32+80+112) m U-shape cable-stayed bridge, the main works of this paper are as follows:1. The ideal elastic-plasticity resistance model was selected to simulate the longitudinal resistance between rails and the girder. An integrative tower-cable-beam-track-pier-foundation was established, considering the influence of the construction stages.2. The shrinkage strain curve and creep coefficient recommended in "Code for design of highway reinforced and prestressed concrete bridges and culverts","Code for design on reinforced and prestressed concrete structure of railway bridge and culvert" and " Eurocode2:Design of concrete structures-Part1-1:General rules and rules for buildings" were applied to analyze the development of additional longitudinal forces and displacement in rails that caused by shrinkage and creep, and the influences of the concrete age of loading and track-laying duration were discussed. The result indicates that shrinkage and creep has a great influence on the additional longitudinal forces in rails and the displacement of both rails and beams, so it should be taken into consideration during the design.3. In this paper, the distribution of shrinkage and creep forces, expansion and contraction forces, flexural forces and braking forces was analyzed separately and the strength of rails was checked, considering the unfavorable combination of longitudinal forces. In addition, the longitudinal forces in rails and the width of breaking joint were checked under a special load case of rail broken case, and the effects of all kinds of additional longitudinal forces on horizontal reacting force at the bottom of the piers were explored.4. The additional forces and additional displacement, caused by the track-bridge interaction when the small resistance fastener was applied, was calculated and studied. Research results indicated that the additional longitudinal force in rails and the horizontal reacting force of the piers can be reduced greatly when small resistance fastener was used.