Zhengzhou Yellow River Railway Bridge Associated Steel Truss Pushing Method Of Construction Technology And Process

The Yellow river highway-railway bridge in Zhengzhou is the longest highway-railway bridge in the world at present. Its steel girder of the main bridge firstly adopted the form of three main spatial trusses whose side trusses are sloping, structure is novel and construction is very difficult. Based on the engineering background of the first-unit steel truss girder (whose total span is (120+5×168+120) =1080m) construction, the author studies the incremental launching construction technique of the steel truss girder with the features such as multiple aperture, long span and long unit. The main work and innovative points are as follows:1. Comparing the traditional technique such as cantilever erection method with the incremental launching construction technique, the author enumerates the possibilities, advantages and disadvantages of each method, then demonstrates the rationality of incremental launching construction technique.2. Comprehensively considering the factors such as construction period, equipments and economy, the author analyses and confirms the incremental launching implemental scheme and the corresponding construction procedures with the concrete bridge deck uninstalled.3. Based on the technical ideas of incremental launching construction of the 168m long span continuous steel truss girder without a temporary pier, the paper studies the main equipments and technological measures in the incremental launching construction particularly, such as the structure of guiding beams, the bracket of piers and abutments, incremental launching equipments, assembling support and lifting machine of the steel beam and the measures for decreasing the friction during incremental launching process.4. According to the bottom chord bar's weak ability of steel truss girder to endure the strong supporting reaction produced by the structure during the incremental launching process, by integrating the advantages of incremental launching method and longitudinal dragging erection method, the paper develops the jobs in a creative way and designs a new slide way and support system, for a better use of incremental launching method to steel truss structure and popularization.5. By using the finite element numerical analysis, the mechanical analysis of the girder during incremental launching construction is accomplished, the stress and stability of the temporary components such as members and guiding beams are checked, and the security of structure and the feasibility of method are demonstrated.6. By combining the above mentioned techniques and processes, the paper uses the incremental launching method to the erection of multiple-aperture long-unit ( 1080m ) long-span ( 168m ) three-main-spatial-truss truss for the first time, and summarizes it systematically, accumulating experience for the construction of similar bridges.