Simulation Analysis of Girder Transport Process on the Box Girder of Hangzhou Bay Bridge

The 50 m box girders in the tidal flat section of unnavigable channel bridge in Hangzhou Bay Bridge adopt the approach of trolley on the under bridge to transport and erect the girder. Based on the actual working and load conditions, a precise 3D solid FEM simulation model is established by taking account of the space effects of prestressing force, applying equivalent node force and taking reasonable consideration of support details, etc. The values for concrete characteristics are determined according to current specifications for the design of highway bridge. The load is calculated with the consideration of the worst factors. The bottom of the support is simulated as rigid element. Modulus of elasticity for girder contact layer will not appear tensile stress when rotations and deformations occur at girder end. Element mesh should be as subdivided as possible when the structure is discretized. Owing to the relative complexity of the stress at girder end, thicker than span intermediate element mesh is adopted for girder end. The integral deformation and the space stress distribution of weight-bearing box girder are calculated. Results indicate that the deformation is relatively small and the maximum deflection is within the reversed arch because the load is quite close to the support. The maximum main tensile stress of the support section occurs at the side of bottom plank surface, which exceeds concrete cracking strength. Consequently, concrete in this area should be treated and stiffened so as to avoid it from cracking. When the maximum main compressive stress occurs near the stabilizer of girder-erecting machine, its value is less than the compressive strength of concrete.