Research On The Key Technology In The Construction Process Of The Semi-supported Long-span Steel Arched Bridges

Steel-box tie-bar arch-bridge has a rapid development in China. In the past twenty years,a great number of the long-span steel-box arch-bridge have been built. These bridges designedwith novelty, construction difficulties, complex technics, and modern taste.However, compared with the design of steel-box tie-bar arch-bridge, the systematicstudy of the steel-box arch-bridge lags behind. The situation derectly impact on thedevelopment of the steel-box arch-bridge in China.Based on the practical work in terms of theconstruction monitoring and the test detection on the steel-box arch-bridge in recent years, theauthor tries to study on the key technology of constructing control in the steel-box tie-bararch-bridge which applies cable hoisting-cable-stayed buckle hanging method with theengineering background in Lan Zhou Zhong Xintan Yellow River.The main content of the task as follows:(1) based on a large number of literature aboard and at home, the author makes asystematical review and summary on the history of development of the arch bridges, and thencomprehensively introduces several construction methods on steel arch bridges.(2) According to the construction order of “first arch then girder” and constructionmethod of cable hoisting-cable-stayed buckle hanging, the key problem can be solvedthrough structure analysis of the bridge in construction process with the accurate simulationof adoption of the finite element software MIDAS/CIVIL.(3) the author briefly introduces the composition of cable suspension system, thetechnical performance and the parameters, and then use the finite element software tosimulate the cable suspension system, to calculate the combination of various types of axialforce and stress force on cable hoisting-cable-stayed buckle hanging system and thehorizontal displacement of top of the tower under any loads. Through analysis and calculationof test on cable hoisting-cable-stayed buckle hanging, the security of the whole process onthe system of cable hoisting-cable-stayed buckle hanging has been ensured.(4)In the course of the cable hoisting on Lan Zhou Zhong Xintan Yellow River,according to the controlling thought of cable hoisting only once, the author applies flexible-rigid support method to calculate in the simulation of finite element construction and to solvethe determination of buckle cable initial tension and main rib elevation. And finally determinethe closure of the bridge.(5) Through the comparison and analysis of the methods on ensuring boom internal force,the author finds some faults, and then adopts a comprehensive method based on matrix toensure the reasonable boom internal force. With adoption of this method, the author alsodetermines the internal force on the staged tensioning force. Thus, the boom can reach thetarget stage through tensioning only once.