Study on the Precise Displacement Controlling Method for a Suspended Deck in the Hanger Replacement Process of an Arch Bridge

The hanger often needs to be replaced many times during the operation period of hanger arch bridges. To ensure the safety of the hanger replacement in the construction process of pocket hanging, the structural response in the whole construction process needs to be precisely controlled. In this paper, aiming at half-through arches with a suspended deck by cable hangers, the precise displacement controlling method for hanger replacement of an arch bridge based on the pocket hanging method has been proposed. Firstly, the equivalent model of an arch bridge in the hanger replacement process is established, and the boundary conditions of the equivalent model are calculated precisely. Secondly, in the hanger replacement process, including old hanger demolition and new hanger installation, the precise displacement expressions of the suspended deck are derived on the basis of the equivalent model. Finally, the correctness and feasibility of the proposed precise displacement controlling method are verified by the hanger replacement engineering of an arch bridge. Through this research on the hanger replacement of an arch bridge, the equivalent model adopted in this paper has been proven accurate, and only partial boundary conditions need to be considered in practical engineering applications to get accurate results. Meanwhile, the calculation results are accurate enough through the practical engineering verification, and the precise displacement controlling method is feasible in the hanger replacement process of an arch bridge based on the pocket hanging method. It is also found that satisfactory results can be achieved using hanger demolition and installation by equal step length.