Railway CFST Tied-arch Structure Stability Parameter Study

In recent years, concrete filled steel-tube （CFST） arch bridge has smallerweight,resistance to deformation, high carrying capacity, construction is convenient,adaptable foundation and other advantages in a highly competitive modern bridge design, isthe ideal long-span arch bridge structurethe form has broad prospects for development in ourcountry. According to incomplete statistics, CFST arch bridges have been built in China hasmore than200, there were40large span and oversized span severalWith the the transport undertakings booming, increasingly high demand on the capacityof the bridge across the wide span ratio decreases, the excessive use of high-strength materials,resulting in drastically reduced structural stiffness, stability significantly.In this paper, use MIDAS software analysis and comparison stability factor, acomprehensive study of the stability of the arch bridge.First, overview of the development and characteristics of CFST Arch Bridge, combinedwith domestic and foreign research CFST Arch Bridge data,system introduced stabilityanalysis of CFST arch bridge.Second,the article describes the arch bridge stable computing theory, including theconcept of structural instability and pointed out that the first class instability does not exist inthe actual engineering, nonlinear analysis of the actual structure of the instability should besecond class.Then,the stability problem solving methods, including static balance method, energymethod, defect method and power method, finite element analysis on the two types of stabilityproblems, get finite element analysis of the mathematical expressions, introduced thedefinition of geometricdefinition and material nonlinearity,and nonlinear effects of the archbridge,Should be pointed out that the finite element method considering the structure ofgeometric and material nonlinear problems.Finally, the existing arch bridge stability theory as a guide,98m taizi river arch bridge asengineering examples,utilize finite element analysis program MIDAS establish a bridge spacefinite element model,consider the double impact of geometric and material nonlinearity,showbridge stability factor of the specific load case and buckling modes,the results show that: thestructural instability mainly instability in the face outside the Rib elastic buckling coefficientswere higher than the regulatory requirements （4-5）, the elastic stability to meet therequirements.Based on a large number of calculations reveals arch beam stiffness ratio,arrangement of transverse brace,boom and other factors that affect the stability of the bridgespace, through the analysis of the calculation results of such bridge design, construction, monitoring, and maintenance has certain reference value, and also provide a reference to theoptimized design of similar type of bridge.