Evaluation Research On Girder Body And Components Of Track Structure Of Bridge Tramcar

When CWR is applied to tramcar track in urban expressway viaduct, it will produce longitudinal force between the beam and rail because of vertical deflection and temperature changes of the beam. Studies show that the longitudinal force impacts on the beam and track structure greatly. As tramcar in bridge is a new attempt, and lack of related research, it is necessary to study the effect of longitudinal force on the structure of beam and track, in order to provide verification and reference for design of beam and track structure.Rail ditch, angle steel and steel backing plate of the track structure are welded each other. Concrete surfacing layer and the lower box girder form a whole composite structure. Beam and surfacing layer of the same bridge form a laminated beam structure. As the cross-section characteristic of composite structure is different compared to the laminated beam structure, the section stress at the same position changes under the vertical loading when considering the transmission of lateral load. The maximum tensile stress of mid-span section increased 19.4 MPa. The maximum compressive stress increased 2.29 MPa, and shear stress of the top roof support section increased 13.6 MPa. The vertical deflection of the composite beam structure reduced 13.7 mm compared to the laminated beam structure, so the composite structure is more favorable in this aspect. The shear lag coefficient of each section of the composite structure has a certain increase than the laminated beam structure and changes obviously near the bearing.After the longitudinal interaction between beam and rail was imposed, stress distribution characteristic of the box girder has changed. Normal stress and principal stress of the middle section,3L/4 section,7L/8 section and bearing section of the box girder are changed more obvious than only the vertical force effected. And the largest increase amplitude of the first principal normal stress of bottom plate and top plate of 7L/8 section is 12.1MPa and 3.59MPa respectively. Shear stress of bearing section changes little, however the position of the maximum shear stress along the height of section changes greatly. Maximum vertical deflection of the beam decreased. Shear lag coefficient of upper plate near increase significantly, when near the bearing section.Angle steel of track structure simultaneously bears bending shear stress and longitudinal shear force. After the effect of longitudinal force, the maximum principal stress and shear stress of angle steel and steel backing plate increased significantly. The result of the superposition of expansion and deflection force is similar with the result of only expansion force. The maximum principal stress and shear stress of angle steel and steel backing plate appears at the same location of the maximum expansion force. The principal stress and shear stress on the longitudinal of angle steel and steel backing decreased with the weaken interaction between beam and rail.