Stability Analysis Of Large Span Concrete-filled Steel Tube Arch Bridge During Construction

With the rapid development of national economy and the improvement of scientific and technological level,the construction of highly developed transportation in the eastern region has been basically completed.In line with the development strategy of the central and western regions of the country,the focus of transportation construction in China has shifted from the developed eastern regions to the central and Western regions.Topography and location have always been a huge obstacle to Guizhou's development.Guizhou is the only province in China that does not rely on plains.Most of the areas are mountainous and hilly.Some areas belong to karst landform,and the surface environment is intricate.Concrete filled steel tubular(CFST)structure is a composite structure developed in recent years,which has the advantages of high strength and light weight.With the addition of new high-strength materials,the application of thin-walled structures and the mature development of suspension construction technology without brackets and cables,it has been one of the preferred bridge types for long-span bridges across mountainous areas.The deck concrete-filled steel tube arch bridge is mostly built in the mountains and valleys with large fluctuation of terrain,which is just suitable for the bridge type selection scheme of complex terrain in Guizhou.Therefore,the stability analysis of this kind of bridge type is very valuable.In this paper,the stability analysis of the super-large arch bridge in Daixiaojing is carried out.This paper introduces the origin and characteristics of concrete-filled steel tube arch bridge,lists some projects which have attracted worldwide attention in the context of rapid development of transportation in modern times,summarizes the current research status of this type of bridge stability,and completes the following work by using large-scale general finite element software MIDAS/CIVIL:(1)A simulation space finite element model is established for a 450-m-span concrete filled steel tubular arch bridge in Guizhou Province,which simulates the characteristics of the main arch rib during suspension construction,analyses the stability coefficients of the arch bridge in each construction stage,simulates the construction process of concrete filling in the tube under the original design scheme,and obtains the stability coefficients and the instability in buckling analysis.Style.The linear elastic buckling analysis of the completed bridge under four load conditions is also carried out.(2)Based on the above analysis process,it is found that the lateral stability coefficient of the model is low in the closure period,and the stability of the two sides of the arch bridge near the arch foot under full uniform load is unstable.The influence of cable wind on the stability of the arch bridge in the construction process is analyzed,and the number of high columns on both sides is discussed and the stability change of the whole bridge under different steel content is analyzed.(3)The structure of the bridge was adjusted,and the number and form of the cross braces of the background engineering were compared and analyzed.The influence of the "meter"cross braces,the "K" cross braces,the "I" cross braces and the "X" cross braces on the stability of the bridge was obtained,and the reasonable layout type and location of the cross braces were obtained.