Performance Evaluation and Reinforcement Measures for Transverse Separated Blocks during Steel Box Girder Installation

Abstract

In order to reduce size and weight during the transport and installation stage, a steel box girder needs to be separated into asymmetrical thin-walled blocks with open sections along the transverse direction. However, the deflection and stress of the separate blocks are quite different from the complete bridge. The present method, based on the variational principle, takes the nonuniform arrangement of the shear braces and the temperature load into account, obtaining the theoretically exact solutions of generalized displacements and stress resultants. The present method can be used to design and optimize the shear brace arrangement and evaluate the performance with and without the reinforcement measures. Then, the proposed method is applied to two bridges with spans of 40 and 65 m to evaluate the effect of shear stiffness reduction and extreme temperature on the installation of the separate blocks. Reinforcement measures are proposed so that the bridges can be completed successfully. The stress results show good agreement with the field data.