Abstract:In order to research the structural behavior of prestressed composite girder bridge with different combination methods, taking a prestressed composite girder bridge with a main span of 70m as an example, the pre-combined and post-combined methods were selected as the comparative analysis objects respectively. The construction process was simulated in detail by using the space finite element model to calculate the structural performance of the composite girder bridge with two different combination methods. The result shows that, after the concrete slab in conventional pre-combined composite bridge was prestressed, part of the prestress was transmitted to the steel girder through shear connectors. However, the concrete slab in the negative bending moment zone was introduced the whole prestress by using the post-combined method. Compared with the pre-combined method, the pre-pressure stress of the concrete top surface in the middle support section is 2.84MPa greater than the latter, the compressive stress of the steel top flange is 46.74MPa less than the latter, and the tensile stress of the steel bottom plate is 4.84MPa less than the latter. The concrete slab constructed by post-combined method obtained more prestress than that constructed by pre-combined method, and the stress increase ratio was 30%, which improves the crack resistance of the concrete slab during the service.
