Determination Of Cable Tension And Optimization Cable Of A Cable-stayed Bridge With Single Inclined Tower And Concrete Girder Based On Forward Iteration Method

The number and scale of bridges with long span increase daily, with the fast development of the national economy and the increasingly rise of the traffic. The cable- stayed bridge is an advanced bridge type of bridge with long span or super span. The distribution of the internal force of the cable-stayed bridge is one of the important criterions to assess the designing quality. As for the bridges at terminative stage, the distribution of the internal force is determined by the cable tension to a great degree. So the main purpose of this paper is to research the optimization of cable tension.Currently, there are a great number of methods to optimize the cable tension. The methods to optimize the cable tension can be sorted into optimization of cable tension with specified stress condition unconstrained condition and constrained condition. As an example of force balance method,minimal bending energy method,rigid support continuous beam method,minimal cable usage method and influence matrix method. In practice, we should select the suitable optimization method according to actual situation.Although there are a lot of acknowledged theories and methods to optimize the cable tension, and each has its advantages and limitations. This Paper uses large finite element software MIDAS to found a model, and after verifying the correctness of the model to carry out the zero derivative optimization analyzing with reasonable variables, and then carry out the first derivative optimization. The deformation of the main beam under the reasonable cable tension meets the requirements after comparing the two internal force state.By reading amount of literatures, whether the result of optimization is reasonable can be judged by analyzing them.Then the unreasonable cable tension is revised to make them to meet the basic requirements.At last, the paper considers how to define the reasonable cable force of Siyang Bridge, and summarizes the determination of the reasonable designing cable force.