Analysis of Geometric Nonlinear Behavior of Self-Anchored Suspension Bridge of Large Span

Considering with geometric nonlinear problem of self-anchored suspension bridge of large span,based on the basic principles of nonlinear analysis,a geometric nonlinear behavior of main cable 's displacement of large span suspension bridge in construction phase and at final stage was studied,by the method of analyzing the bridge's geometric nonlinearity by loading fractionally. Besides,based on the comparison between theoretical calculation and measured experimental total bridge model test,the geometric nonlinearity characters of the main cable were clarified. The results show that the geometric nonlinearity character of the main cable's displacement is obvious,and it mainly experiences three segments: linearity character is obvious,nonlinearity character enhances gradually and nonlinearity character reduces gradually. Further analysis shows that the changing rules of the nonlinearity character of a cable band spot under tensioned or not are different: the geometric nonlinearity character in the zero-crossing points of displacement influence line of the main cable is much more obvious than the other parts of the main cable. Under complete bridge stage,the linearity character of the main cable's displacement is obvious and the load effect fits the superposition principle.