Crucial Construction Technology Study Of Three-span Spatial Cable Self-anchored Suspension Bridge

Self-anchored suspension bridge is developed on the basis of traditional earth-anchored suspension bridge,is a new type of bridge with unique stress form and appears in people's field of vision in the form of its light appearance.As bridge technology changes quickly in western countries,self-anchored suspension bridge has been developing very rapidly.Compared with western developed countries,Chinese practical experience in the field of self-anchored suspension bridge,related researches and articles are less than western developed countries.Therefore,this paper takes Songyuan Tianhe North Bridge,which is a double towers and three-span spatial self-anchored suspension bridge,for the research background of practical bridge,and researches the main cable linear of completed bridge,the main cable linear of initial state of equilibrium and the process of system conversion were studied.This paper's main research contents are listed as follows:1.Through reading plenty of domestic and overseas research articles and informations related to self-anchored suspension bridge,this paper summarizes development situation and research status of domestic and overseas self-anchored suspension bridges;Then introduces the bridge type,main components,characteristics,advantages and disadvantages of self-anchored suspension bridge;Finally,this paper simply expounds the methods of analysis theory and calculation theory of suspension bridge,including static analysis method under the vertical,horizontal and off-centered load and the calculation theory of main cable linear,etc.2.This paper is based on the theory of node lines method,through the MIDAS/CIVIL software establishing finite element model and making an analysis for main cable linear of completed bridge of Songyuan Tianhe North Bridge,consequently got coordinate of main cable linear of completed bridge,unstressed cable length of main cable and unstressed cable length of steeve,and then corrects the unstressed cable length which lies in cable saddle and encases saddle groove,consequently got main cable designed length of Songyuan Tianhe North Bridge.Based on the principle of main cable's unstressed length being constant,through the MIDAS/CIVIL software making backward analysis for main cable linear of completed bridge cavity,consequently got the main cable linear,namely the main cable linear of initial state of equilibrium.Finally the paper calculated the pre-bias of main cable saddle,providing basis of data for pushing of cable saddle in the process of system conversion.3.The paper studied and analyzed system conversion of Songyuan Tianhe Bridge at the end of paper.System conversion is key construction technology of self-anchored suspension bridge,through the process of sling tensioning,stiffening girder and temporary piers separate gradually,so the load of the main cable is born by stiffening girder,and makes continuous beam system into suspension system.Then according to the different tension sequence and tension cable force control,four schemes of sling tension are worked out in this paper.Finally,through comparing four kinds of schemes,the paper chose the most reasonable and economic sling tensioning scheme.