Nonlinear Analysis For Stability Of Concrete-filled Steel Tubular Arch Bridge

Owing to the many advantages such as high carrying capacity, upstanding plasticity and toughness, better economic effect, the concrete-filled steel tubular arch bridge have resolved two difficult problems, one is that the material of high intensity apply the long-span arch bridge, the other is construction. It's a structure form that has wide developmental foreground in the arch bridge. The concrete-filled steel tubular arch bridges have been more and more widely used in bridge structure in China. However, arch bridges transmit the applied loads to axial force mainly, which makes arch bridge uniquely susceptible to bucking failure, especially with the slender arch ribs. So, it's importance to study stability of concrete-filled steel tubular arch bridge.In this thesis, firstly, the fundamental theories of nonlinear finite element and stability of the arch bridge are detailedly described. The nonlinear solutions and the solutions of stability in arch bridge are discussed. Second, the reasonable calculation model is chosen to calculate the stability of real Bridge in construction by means of the finite element program ANSYS based on the fundamental theories of nonlinear finite element method. The stability of the modes with the linear elasticity and the elastic-plasticity in construction are calculated and analyzed. The first-class stable safety coefficient, unstable mode and the second-class stable safety coefficient on various loads are obtained. The structure safety coefficient and the influence of the different non-linear modes on the stability are compared. At last, base on the basic theory of nonlinear and stability analyses, different parameters , such as arrangement form of the lateral brace, the sloping angle of the arch ribs, the rise-to-span ratio, the arch axis coefficient and the stiffness of the arch ribs, are discussed in order to analyze the influence to the stability of arch. In project reasonable parameters can be choosed to improve the stability of the concrete filled steel tubular arch bridge.Above all, the present results can provide a practical reference for design and construction of the concrete filled steel tubular arch bridge.