Geometric Nonlinear Static Analysis Of HongSha Cable-Stayed Bridge

This thesis focuses on geometric nonlinear static analysis of long-span cable-stayed bridges. The basic theories of geometric nonlinear analysis about long span cable-stayed bridge are introduced. Then three principle factors that affect geometric nonlinearity of cable-stayed bridges are described, which are large displacement, effect of cable sag and combined effects of moment and axial force; then the finite element methods are introduced separately. And then, the finite element model of HongSha bridge according to its scheme with single pylon is erected by ANSYS, a general finite element software. In this thesis presents the methods to simulate the real load-bearing condition of bridge structure, effects of cable sag and erecting and removing of element under construction stages. At last, the linear and nonlinear analysis of construction stages is made. According to the comparison between those results, conclusions are drew as-followed:(1) In comparison of cable force, the value of the same cable tensile force is range in 5%. The geometric nonlinear factors have some effect on cable tensile force, and the value of cable forces become almost a constant after the bridge is finished.(2) In comparison of the vertical deformation of beams, The geometric nonlinear factors show obvious effect in construction stage. Among the three geometric nonlinear factors, large displacement and cable sag has the larger effect, and the combined effect of moment and axial force has the less effect. Therefore it is important to have some the geometric nonlinear analysis in construction stages.(3) In comparison of the moment value, The geometric nonlinear factors have obvious effect in every construction stage. Among the three geometric nonlinear factors, large displacement and cable sag has the larger effect, while the combined effect of moment and axial force has the less effect.(4) There are two reasons to make the combination effect of moment and axial force has less effect to the bridge structure. one is the problem of partial compressed is solved successfully in section design stage. The other one is the space between cables is small enough to reduce the moment value.(5) The dissymmetry of design leads to different internal force and deformation of the left bridge and the right part. And internal forces of the right bridge are larger than the left one.