Nonlinear Analysis And Construction Control Of Cable-Stayed Bridges

In this thesis, the nonlinear static analysis of cable-stayed bridges under the effect of their own dead weight and a set of initial cable tensions is formulated. All sources of geometric nonlinearity, such as cable sag, axial force-bending moment interaction in the bridge deck and towers, and change of the bridge geometry due to large displacement, are considered in the analysis. The thesis presents a method for modeling cable-stayed bridge for nonlinear finite element analysis. That is to adopt space truss-beam model to simulate the whole structure system. The system equation of cable-stayed bridges including all of the nonlinearities is first set up and then solved using the Newton-Raphson method on increment-iterationwise. This thesis presents a more effective convergence criterion and dichotomy to solve this problem. The examples in the thesis have shown the use of the new convergence criterion and dichotomy. And the results of the examples are very reasonable.On the other hand, the investigation about the reasonable cable tensions and the control force in the construction is presented in the thesis. An optimization method for determining the initial cable tensions due to dead load is presented in the thesis. This method is based on the minimum of bending energy under dead load. And it is probably a better method to determine the reasonable cable tensions in the optimization methods. The idealized nonlinear back-running analysis is also discussed in order to calculate the cable-stayed bridges' construction. By this analysis method, the optimization results of the structure can be finally achieved in construction. In order to keep the integration of the construction control, the principles, processes and methods are also presented.From this study, the following conclusions may be made: It is accu-ate and reasonable to use a rather simpler space truss element to model the cables in cable-stayed bridges. The method to solve the convergence in the nonlinear analysis is reasonable and effective. And we got very ideal results in the construction control analysis by the methods put out in the thesis.