Researches On Reasonable Stress Of Optimizing PC Cable-stayed Bridge From Its Construction To Completion

Cable-stayed bridge is a highly hyperstatic bridge with flexible feature, but its cable tension is changeable and adjustable from its construction into completion. Moreover, Cable force plays the distinct role in the stress and deformation, which has great troubles in designing cable-stayed bridge. Therefore, many researches have been done on its cable tension at home and abroad and also some approaches been put forward. Usually, due to the complicated calculation and one-sided method, it takes the workers lots of time to calculate the numbers. According to the existing theory, the thesis consists of five main points as follows:1.The thesis gives the general survey of the development, the international position of our cable-stayed bridge as well as the common methods taken by cable tension from the period of its construction into completion and then makes the comparative of these methods.2. Based on the previous theory, it proposes the method of inherent stress and cable tension which have an effect on PC cable-stayed bridge from its construction into the bridge. Meanwhile, under the guidance of the theory, the relative mathematical optimization model is established and then some technological methods are taken to cope with this model.3. It describes the optimization algorithm, namely, the development and application of the dual simplex method. It also elaborates on its basic principles and steps of the algorithm, and then illustrates its correctness and stability of the algorithm.4. It applies influence matrix method, instead of gravimetric analysis of the structure to calculate cable tension so that it can shorten the calculation time to improve the computational efficiency5. The theory is combined with practice. In other words, this method in the thesis is applied to double tower PC cable-stayed bridge. The author makes use of commercial software TDV to verify the calculation, and then makes the comparative analysis of the optimized calculation results. It turns out the fact that after optimizing the cable-stayed bridge, the cable tension of its components is more reasonable, and that the amount of presstressed reinforcing steel is greatly decreased to reduce the project cost. Consequently this method is correct and effective in solving the cable tension.