QR-Method For Nonlinear Stability Analysis Of Long-Span Concrete Filled Tube Arch Bridges

In this paper, firstly, the recent condition, the types of structures, the mechanics performance and perspective of the fast developing CFST arch bridge are introduced. Secondly, the recent research condition for the stability of structure and the author's study are introduced.In this thesis, the problem of nonlinear static stability analysis of long-span CFST trussing arch is mainly researched. Firstly, the author establish the functions of stability on the basis of the spline function method(QR-method) ,according to the theory of geometrical nonlinear and the theory of stability, educe the stability equation of structure based on variational principle, then carry through the flexuosity analysis of CFST arch.The big distortion geometrical nonlinear was considered by the stability equation,the author simplified the problem of geometrical nonlinear through ignored quadratic term and reserve the simple term, at last boiled down to solve the linear stability equation of eigenvalue . The author established the new arithmetic of nonlinear stability analysis and the guide line of the style of lost stability. Lastly, the relevant computer programs were completed with Clanguage and MATLAB.The author validate the correctness of the method through some examples. At the same time, the author analysis the problem of nonlinear static stability of the practical engineering. It was compared between the results of QR-method and FEM, and we can find that the results of QR-method have a high accuracy. The method doesn't adopt FEM principle on theory, so it avoids some enormous difficulties and disadvantages resulted from traditional method. When QR-method is used to analyzing the static stability of long-span CFST arch bridges, the result show that this method is not only high accuracy but also the number of unknown quantity is fewness and computed simply and it has better convergence performance, it can be actualized easily by computer, so it is a effective and economic new method.This paper not only has the theories signification but also has the reference value in engineering practice.