SPATIAL TRANSFORMATION CONTROL METHOD OF MAIN CABLE ALIGNMENT DURING CONSTRUCTION PROCESS IN SUSPENSION BRIDGE WITH SPATIAL CABLES

Due to large lateral deviation between the free cable state and the finished bridge state, the alignment transformation of spatial cable suspension bridges during construction directly affects the installation and extent of buckling damage in the hangers. Through the analysis of the lateral deviation and drift angle in a typical project, the effects of and strategy for alignment transformation in different bridges are revealed. Computational formulae are provided to represent the lateral drift angel of hangers in different working conditions. A new method, named temporary lateral bracing between cables, is proposed, and its corresponding devices and clips are invented. This method effectively solves the alignment transformation and hanger installation problems in a spatial cable suspension bridge which occur in the “erecting girder after constructing cable” construction method. Engineering application and numerical analysis show that the proposed method can be applied in both “erecting girder after constructing cable” method and “erecting girder before constructing cable” method, and its advantages include high efficiency and large safety redundancy. It can be installed in place without adjustment, does not restrict or affect the development of the construction process, provides a rigid support to the lifting point, offers a better control of drift angle, has a greater safety margin for construction error, is adaptive to the complex adjustment in the process, and is easy to implement.