The Research on the Nonlinear Stability of the Steel Spatial Arch Truss with 120m

Abstract

In this paper, the elastic stability and elasto-plastic stability analysis on the steel spatial arch truss with 120m span and 0.2 rise-span ratio is carried out with the finite element program ANSYS. In the analyses, three conditions which are the geometric ,the geometric and material nonlinear, double nonlinear under different initial geometric defects are considered. The results show that the instability mode of arch trusses are all asymmetric instability of plane, and that the buckling load of considering double nonlinear is 13.84% that of considering geometry nonlinear, and that the coupling effect of geometry nonlinear and material nonlinear has accelerated reducing the stiffness of structure and bearing stable capacity ,and that the ratio for the buckling load of the four arch trusses with L/500, L/400, L/300 and L/200 initial geometric defects is 1.0: 0.927: 0.904: 0.87: 0.804, and that load-displacement process curves of feature node are the same change for the structures under different initial geometric defects.