Research On Incremental Launching Construction Method Of Steel Box Girder Of Jingshan River Bridge

With the development of society,there are more problems that need to be overcome in bridge construction.Among them,the bridge pushing technology with poor geology,large span,and variable curvature is also facing unprecedented challenges.Taking the Jingshan River Bridge as the engineering construction background,this paper studies the use of walking-type jacking construction method to push the long-span steel box girder with the vertical curve of variable curvature into place in the case of extremely poor geological conditions,and mainly discusses the variable curvature steel How to adjust the box girder elevation.The first part of the content uses the general modeling method of the bridge business program Midas Civil to establish a finite element calculation model.The beam element simulates all components.Calculate the stress of steel box girder and guide girder and bridge piers(main bridge pier and temporary pier)under several main construction stages,and analyze and calculate the sensitivity of vertical fulcrums.The main purpose is to verify that the steel box girder is pushed in the whole The safety in the process pave the way for the analysis content of the later adjustment of the elevation;The second part of the content uses Midas Civil’s two major modeling assistants to establish a finite element push calculation model.The single-step modulus search synthesis method is used to optimize the adjustment of the fulcrum elevation.Based on a beam drop,the forced displacement simulates the support elevation.Finally,the optimal adjustment plan is obtained,and the numerical changes of each control item are summarized as the pusher advances,so as to ensure the adjustment and optimization of the elevation in the process of safe pusher.The third part is to design an innovative suspended temporary structure,which does not rely on the ground but can increase the density of the jacking device to achieve the optimization of the adjustment elevation of the variable curvature vertical curve long-span bridge,using Midas Civil Establish a finite element jacking calculation model III,convert the vertical pressure of the bridge to the pier into the horizontal force component to the pier,and discuss the force of the temporary structure and the pier when the temporary structure is weighted and the pier is pushed to ensure The feasibility of the temporary structure and the law of change are summarized.There are ways to solve all problems,but the ways to solve them vary.Finally,the two elevation adjustment schemes are briefly compared in terms of construction,economy,and construction period.