Structural Optimization Design Research Of Multi-span Composite Beam Extradosed Cable-stayed Bridge Based On Incremental Launching Construction

Extradosed cable-stayed bridge is a beam and cable system bridge between continuous(rigid frame)bridge and cable stayed bridge,because of the late emergence,the relevant information is relatively scarce and simple,lack of depth.With the rapid development of incremental launching construction technology,the bridge which adopt entirely incremental launching construction will have the advantages of short construction period,high construction safety and low construction cost.But at this stage the entirely incremental launching construction application of composite beam extradosed cablestayed bridge is rarely heard.Based on this,this paper systematically and comprehensively studies the structural system of the multi span composite beam extradosed cable-stayed bridge and its specific entirely incremental launching construction,and provide theoretical reference for the design of the same type bridges.The research work of this paper is carried out in two aspects: optimization analysis of structural system and optimization design of incremental launching construction.The main research contents are as follows:(1)Study the influence of main structural design parameters and various temperature effects in cold regions on the common structural system of extradosed cablestayed bridges;Combine the various factors and design the corresponding orthogonal design;And give some suggestions on the selection of structural system and the optimization of structural parameters of multi span extradosed cable-stayed bridge in cold area;(2)Discuss the construction of combining the time of the concrete deck and steel girder,through certain quantitative analysis,summarize the rules,and put forward reasonable construction order of main girder;(3)From the point of view of analytical analysis and finite element simulation,discuss the feasibility of applying the analysis of the main beam of the classical continuous beam system to the multi span extradosed cable-stayed bridge.Summarizes the parameters of the nose girder which is suitable for the entirely incremental launching construction of the extradosed cable-stayed bridge,and study the influence of the parameters of the nose girder on the cable force.Finally,this paper Systematic and comprehensive optimization analysis of the important design parameters of the multi span extradosed cable-stayed nose girder in the entirely incremental launching construction.To summarize,this paper focuses on the optimization analysis of structural system and the optimization design of incremental launching construction,the results of research can provide reference for design and construction of extradosed cable-stayed bridge based on incremental launching construction in cold area.