Temporary Shear Brace Design Method for Steel Box Girder Viaduct in Transverse Block Construction

Transverse block of a steel box girder viaduct can decrease the shear connection between the upper part and the lower part. As a consequence, deflection and deflection difference between blocks are significant, and the performance of weld seams and finished viaduct can be affected. To decrease the deflection of steel box blocks with an open section after transverse discretization, a piecewise uniform arrangement of temporary shear braces is proposed on condition that the total shear stiffness of the shear braces remains unchanged. First, the formulas for slip, axial force and deflection with a piecewise uniform arrangement of temporary shear braces are given, and the accuracy is verified by comparing the results with finite element method. The proposed formulas are applied to two field studies and the results show good agreement with measured data. Finally, the optimal arrangement of temporary shear braces was explored by the sequential quadratic programming optimization method. The deflection and the deflection difference at welding position are reduced significantly after bracing, and the optimal shear braces arrangement is to arrange the braces more at the ends of the blocks.