Effect of temporary bracing system on the overhang deflection in skewed bridges during deck slab construction

During construction of the deck slab in steel girder bridges, fresh concrete weight and the finishing machine weight produce torsional moments in exterior girders due to the overhang cantilevering in the transverse direction. Therefore, the overhang deflects leading to non-uniform slab thickness. Contractors utilize temporary bracing systems to assure the stability of bridge girders during the pouring of the slab. A temporary bracing system that comprises of diagonal pipe and transverse tie was field examined and its effectiveness was evaluated using FE modeling in non-skewed and skewed bridges. The system was able to reduce the temporary increase in rotation of exterior girders in skewed bridges by 64%. The relative deflection of the overhang was also compared to the overall slope of the slab during construction. Results of this study showed that installing the bracing system provides a more uniform slope in the slab along the span of skewed bridges.