Finite Element Analysis Of Geometrical Nonlinear Behavior And Stability Of Large-Span Bridge With High-Pier

In the recent years, large-span bridge with high-pier has been growing up rapidly with the development of transportation enterprise. The problem of nonlinear behavior and stability of bridge becomes more and more important with the increase of its span and pier height.This thesis illustrates the geometrical nonlinear theory of bars system, introduces the spatial description methods of structural shapes of geometrical nonlinear behavior and emphasizes the discrimination between Total Lagrangian Formulation and Updated Lagrangian Formulation in Lagrangian Formulation. In spatial co-rotational coordinate system, Co-rotational Formulation is introduced in details and then the formula of the increment of nodal displacement which really causes the deformation of spatial beam element in its motion from t moment to t + â–³t moment is acquired. Moreover, the basic principle, advantages and faults of increment method, alternate method and mixed method are expounded. Then, some kinds of the convergence criterion in common use are introduced.Spatial beam element is adopted to simulate large-span bridge with high-pier. Program lyg with visual user-interface, which can deal with geometrical nonlinear behavior and stability, is developed using object-oriented language-Visual C++. Total stiffness matrix is formed using one dimension conservation and nodal displacement vectors are compiled automatically in program lyg . The static problems including geometrical nonlinear behavior of two classical examples are finished using program lyg and commercial software ANSYS . Then, the stability of the first and the second type including the geometrical nonlinear behavior of the Bu-liu He Bridge which is located at Longtan in Guangxi province and is a three-span continuous rigid frame bridge of prestressed concrete is also calculated using software ANSYS and program lyg . In order to conform the reliability of program lyg , two results obtained from program lyg and software ANSYS respectively are compared. Furthermore, a static elastic analysis and geometrical nonlinear analysis of the whole bridge are carried out using program lyg in order to illuminate the influence of geometrical nonlinear behavior on bridge stability. The theoretical calculation formulation of stability coefficient A of high pier, cantilever casting construction and the whole bridge on the continuous rigid frame bridge is acquired...