Application Of Unstressed State Method: Construstion Monitoring Of Cable-Stayed Bridge

Due to the large spanning capacity, the less limited clearance of the deck elevation and the under the bridge, and the good stability of wind, the cable-stayed bridge is widely used in a range of modern bridge structure. Because of complicated structure, high statically indeterminate and complicated construction process, the quality of the construction process, which is vitally important to determine the reasonable structure of a bridge state. In my study the application of Unstressed Stage Control Method are researched in bridge construction control. The dissertation is divided into four parts below according to its content:PartⅠ: It introduces the development process and the important progress achieved of the cable-stayed bridge, then the purpose, the methods, and the need for construction control and main cable-stayed bridge construction control tasks are summarized. In a simple example of a zero displacement method, the minimum bending energy method and the Influence Matrix Method the impact on Rational Bridging Cable Force status, it was analyzed and compared, the calculated results show that: the different varieties of methods can achieve a reasonable bridge state at the state of not shrinkage of concrete creep effect. Finally, common reasonable cable force issues are summarized and explained;Part Ⅱ : It introduces the theory of Unstressed Stage Control. In order to calculate unstressed cable length divided the effects of the two calculation methods sag different situations, and the tower beam element unstressed curvature determined; At the same time, the two basic principles of Unstressed Stage Control was introduced.Part Ⅲ: Taking a steel box girder bridge when no excluding the creep effect of the concrete as an engineering example, it describes the process of solving the calculation of reasonable length to bridge unstressed state in detail, discusses the Unstressed Stage Control method for modeling cable-stayed bridge in stages the construction process. As the calculated results show that: the state of Unstressed Stage is a contrast, it does not vary with changes in the structure formation process changed, thus it verifies the correctness of the theory of Unstressed Stage Control method. Finally, comparing the differences between General closure method and Forced closure method to the effects of internal forces.PartⅥ: Taking a prestressed concrete cable-stayed bridge of Ying De of Guangdong Province as an engineering example, Stress-free method of construction of the bridge was monitored. In order to verify iterative analysis closed divided the effects of the two situations of the effects of concrete creep. Then it discusses on the application of Iterative Method in Bridge Construction Control: the determination of construction force, the extraction of the geometry Precamber, the bridge Construction Monitoring Instruction, and the monitoration to the ultimate goal. Finally, the important bridge control parameters(such as the girde displacement and stress; the tagen stress and the pylon stress) are sensitivity analysised. The outcome of Beijiang Bridge’s monitor is the validity and reliability of this method...