Research On Track-bridge Interaction And Its Influencing Factors Of The Long Span Simply Supported Steel Truss Bridge

ABSTRACT:The longitudinal force that due to track-bridge interaction plays a major role on the design of rail and bridge pier. Its research is of great important significance. Up to now, there are not so much works on track-bridge interaction of simply-supported steel truss bridges that widely used in the railway, while the influence of adjacent ranging bridge for the steel truss bridge is not clear enough. In this paper, based on a156m long-span simply supported steel truss bridge of Huangling-Hancheng-Houma Railway line, some research had been done in the distribution of continuously welded rails(CWR) longitudinal force on the bridge, considering track, adjacent bridge, roadbed, piers, etc. Main content of this paper is presented as follows:1. Based on the ideal elastic-plasticity resistance model, an rail-beam-pier space finite element model was established. The nonlinear spring elements were used to simulate the track resistance and the beam element with rigid arms was used to simulate the bridge.2. The distribution of longitudinal force due to temperature variation, bridge deflection, braking force and breaking force of long rail in long-span simply supported steel truss bridge was analyzed. On this basis, each additional longitudinal force was combined, while the strength of rails and the width of breaking joint were checked. The results show that the longitudinal force due to temperature variation plays a major role among the four, and the maximum rail force is at the movable supports of steel truss bridge.3. The factors that make an impact on the track-bridge interaction of steel truss bridge were explored. The influences of longitudinal forces distribution were analyzed such as truss structure of steel truss girder, whether setting longitudinal beam disconnecting, whether setting adjacent bridge, the long-span continuous bridge was simplified by simply supported bridge, bearing arrangements of adjacent simply supported bridge, track longitudinal resistance model, pier longitudinal stiffness. The decreasing of track longitudinal force by arranging small resistance fasteners or track expansion device was analyzed. The results show that the adjacent bridges have significant influences on the track-bridge interaction of steel truss bridge. The arrangement of small resistance fastener could not meet the track strength requirement, so the arrangement of track expansion device was suggested to use.