Study On The Key Construction Technique Of Incremental Launching Method For Long-span Hybrid Bridge Of Girder And Arch

In recent years, with the rapid development of the construction method, the incremental launching method is expanding the range of application. This paper sets assembled and overall pushing construction method of Jiubao bridge as the background, the researches on the construction technology of incremental launching method for long-span continuous combination system bridge of girde and arch are carried out.The arch rib of Jiubao bridge is warps linear in space, however,it’s extremely difficult to control installation precision and linear,once the deviations occur, it is easy to produce internal stress. In order to ensure the accuracy of controlling linear,some main works will be studied firstly,such as the comparison and selection of lifting equipment and main girder arch assembly process, the technology of main girder arch assembled linear control.According to the design requirements, the three span main arch structure of Jiubao bridge needs overall pushing,because of long span and ultra-high structure, it is of difficulty and high-risk to uses conventional drag-pushing method for this bridge, so a new pushing construction method which is the walking-pedrail translational incremental launching method is developed specially. In this paper, there are some details which are about the description of walking-pedrail translational incremental launching device and tectonic theory, principle of pushing construction, research of control systems. To reduce the internal forces of the main arch structure in the construction process,it optimizes t the length, stiffness and weight of the guide girder device;at the same time,to reduce the boom length in the process of pushing the main arch and improve the stress during pushing the main beam, it takes the comparison and selection study for structure form of temporary braces in the process of pushing.Finally,the space finite element model is established for this Bridge, which makes a detailed analysis of controlling linear, pushing construction stress and system conversion according to0.5m a pace,then,it can determine the most dangerous load of arch and stress and deformation under this condition,only for that,it can ensure the smooth progress of Jiubao bridge construction.