Research On Incremental Launching Construction Safety Control For Long-span Steel Box Girder Bridges

With the rapid development of economy and the increase of bridge span, steel boxgirder bridges develop rapidly in the bridge construction. In recent years, steel box girderbridges with its the advantages of light weight, high stiffness, convenient installation andnovel structure has been widely used in China. The box girder bridges were generallydesigned in constant cross section, which are fit for incremental launching construction.However, due to the particularity of incremental launching method, there are large technicalrisk in the construction process, and the stress system of steel box girder constantlytransforms in the construction process, structural complexity, strengthen the control ofconstruction risk and the safety of the structure can contributes to the bridge to ensure thesmooth of incremental launching construction. So this paper mainly carries out theincremental launching construction of long-span steel box girder bridge construction safetycontrol. Based on real projects, the safety control of the same type, for the incrementallaunching construction of long-span box girder bridges, is studied in this paper. The mainwork of this paper is listed as follows:(1) The content and method of the construction control of bridges and the structuralanalysis method are researched and summarized.(2) Using the finite element software Midas/civil, the overall structural performance oflong-span steel box girder bridge is analyzed during incremental launching constructionprocess, which provides the reliable basis for construction monitoring, and evaluates theconstruction safety through site regulation results. Through the whole analysis results, thelocal stress of steel box girder under the most unfavorable conditions are analyzed, and thenthe effect of the increase of local stiffeners and two measures local stress area of stress onlocal are analyzed. Aim at the stress problems in the process of incremental launchingconstruction we optimize the structure facilities of incremental launching construction.(3) The potential risks during the incremental launching of long-span box girderbridges are identified with the method of scene investigation, and the risk estimation systemis established. Based on the Analytic Hierarchy Process (AHP) and the Fuzzy Comprehensive Evaluation (FCE). According to the evaluation result and experience ofconstruction, risk control of incremental launching construction of the long-span steel boxgirder bridge is done.