Optimization and Evaluation of Pipe-Tie System in Limiting the Exterior Girder Rotation during Deck Construction

The construction of a bridge deck often introduces significant loads acting on the bridge girder system. These loads generally come from the construction equipment, the weight of fresh concrete, and the construction personnel, sometimes resulting in excessive rotation of the exterior girder during deck construction. To limit the girder rotation, temporary bracing systems are commonly used in the United States during bridge construction. The traditional temporary bracing system uses block-tie systems to resist the torsional forces in the girders; however, this system often loses its effectiveness due to the tightening issues of ties and the improper shimming of timber blocks. In this study, a new temporary bracing system-pipe-tie system-is developed to limit the girder rotation during deck construction. This system utilizes diagonally placed steel pipes and ties between girders to resist the torsional forces and limit the rotation of girders. To optimize the sizes of steel pipes and ties, and the spacing between the bracings, finite element analyses are conducted to evaluate the performance of the pipe-tie system under different scenarios during deck construction. Recommendations regarding the size of pipe and ties and the ratio of the bracing system spacing to girder depth are given based on the results from the parametric analysis in this study. This study provides a guideline for designers and engineers to implement the pipe-tie system for rotation prevention during deck construction.