Study On Static And Dynamic Stability Of CFST Arch Bridge Of High Speed Railway

With the continuous development of the bridge design capability and construction technology in China,the spanning capability of bridges has been continuously improved.The concrete-filled steel tubular arch bridge itself has good mechanical properties,simple construction methods,and good economy.In addition,due to the continuous application of techniques such as swivel construction and cable hoisting,the span has exceeded the 500 m mark.Concrete-filled steel tube arch bridge has become a hot-spot bridge of long-span bridges.The continuous growth of the span will inevitably lead to a continuous decline in the wide-span ratio,which makes the stability of the concrete-filled steel tubular arch bridge more and more worthy of attention.Using the static elasto-plastic analysis(Pushover)and dynamic elasto-plastic analysis statics,the non-linear analysis of rod-like unit materials was realized,and compared with the experimental model of the related literature,a more practical analysis result was obtained.In this paper,the related theories of the stability calculation of concrete-filled steel tubular arch bridges,the finite element analysis theory and the solving methods of nonlinear problems are introduced.The nonlinear analysis of materials for the Midas/Civil rod structure cannot be performed well,resulting in the problem that the rod structure cannot be considered for the stability analysis of the material nonlinearity.For the engineering example of the Haozhou Bridge,the Midas/Civil software was used to analyze the linear elastic stability,geometric nonlinearity,and dual nonlinearity(geometric nonlinearity + material nonlinearity)static stability analysis.The analysis results show that the geometric nonlinearity has little effect on the stability of the bridge.Considering the dual nonlinearity of geometric nonlinearity and material nonlinearity has great influence on the stability of the bridge.In this paper,the influence of the factors such as cross bracing form,failure of the boom,arch rib inclination angle,arch rib stiffness and initial flaw on the elastic stability of the bridge line is studied,which provides a reference for bridge design and construction.Finally,the related theory of structural dynamic stability is introduced,and the research on the dynamic stability of the bridge under earthquake is carried out,which provides a reference for the seismic design of bridges.