Large Span Cable-Stayed Bridge Analysis Of Geometric Nonlinear Influence During Construction

To better study the influence of geometric nonlinear on the stress and stability of cable-stayed bridges during construction,with the background of Yanpingba Yangtze River Bridge,the paper analyzed the influence of three geometric nonlinear effects on the internal force and displacement of cable-stayed bridges,based on the MIDAS/CIVIL and the geometric nonlinear theory.The stability of cable-stayed bridges was analyzed by utilizing the displacement control method and the function of"transforming the internal forces of the components in the final stage to the initial load in the Post C.S stage".The main work and research contents of this article are as follows:(1)An overview of the development of cable-stayed bridges,relevant theories during the construction phase of cable-stayed bridges,and a detailed introduction to the three geometric nonlinear factors involved in the analysis of cable-stayed bridge construction process and the methods and convergence of geometric nonlinear analysis guidelines.(2)An overview of the engineering background of the Yanpingba Yangtze River Bridge.Based on the construction sequence and construction characteristics of the actual project,the MIDAS/CIVIL spatial finite element model was established,and the structural internal forces in the typical construction stage that took into account geometric nonlinear factors were calculated.(3)Analyzed the influence of three geometric nonlinear effects(stay cable sag effect,second-order effect,large displacement effect)on the internal force of the cable-stayed bridge during the construction stage,and explained the main reasons leading to the nonlinear increment.Finally the influence of structural system transformation of cable-stayed bridge on the structure is analyzed.(4)The stability analysis theory of long-span composite beam cable-stayed bridge is discussed.The linear buckling analysis and geometric nonlinear buckling analysis of the typical section during the construction of the cable-stayed bridge are carried out to obtain the stability coefficient and buckling mode of the typical section.Through the comparison of linear and nonlinear buckling analysis,it can be concluded that the overall structural stability analysis during construction takes into account the importance of geometric nonlinearity.