| In the recent decades, cable-stayed bridges have become one of the most popular types of bridges, as they provide an economical solution for medium to long span bridges and possess excellent structural characteristics and aesthetic appearance. Cable-stayed bridges generally exhibit nonlinear behavior under normal design loads. With high compressive forces in both girders and pylons, stability of such bridges has been concerned by the researchers and engineers. Nonlinear behavior and the load-carrying capacity of cable-stayed bridges are the subjects of this study.; Since the general finite element packages are usually not convenient or cannot conveniently handle the special features of cable-stayed bridges, it is desirable to develop a special procedure for analysis of such bridges. An energy method for analysis of nonlinear behavior and the load-carrying capacity of cable-stayed bridges is proposed in this dissertation. The potential energy of the whole bridge, including the bridge deck, stayed cables and pylons, and the work done by external loads are considered in the development of the bridge energy equation. The sources of geometric nonlinearity, such as the cable sag, axial force-bending moment interaction in the bridge deck and in the pylons, and the material nonlinearities are taken into account in this analysis. A trigonometric series has been used to describe the deflections of the bridge deck, and a trigonometric function has been used to express the lateral deflection of the pylons. An iteration procedure which has a high convergence rate for solving the problem is given.; The proposed method is efficient and simple to use. The approach may make it possible that the analysis of nonlinear behavior and load-carrying capacity of cable-stayed bridge can be done by use of a personal computer. The predictions of the method show good agreement with the experimental results. The proposed method can also be used for the nonlinear analysis and calculation of load-carrying capacity for different types of cable-stayed bridges, such as the bridges with harp, semi-harp, fan or star types of cable configurations. |
