Cable Force Optimization Under Finished State And Determining Of Reasonable Construction State Of Multi-Pylon Cable-Stayed Bridge

Multi-pylon cable-stayed bridge is a new type of cable-stayed bridge structure system, developing in recent years, which has complicate force and structure, and has significant spatial effect. Under determined loads, one key issue for the design and construction of multi-pylon cable-stayed bridge is the determination of its rational cable force in finished stage and rational construction state, so as to make the indicators reach optimal, which reflect one certain kind or several kinds of performance, Taking Jiashao River-Spanning Bridge—six pylons four cables and separated decks cable-stayed bridge as engineering background, this thesis systematically studies the method to determine the rational cable force in finished stage and rational construction state of this kind of cable-stayed bridge. The main contents are as follows:(1) The present various domestic and foreign methods, which have been used to determine cable force optimization in finished state and the reasonable construction state of cable-stayed bridge, are analyzed and discussed comprehensively, and the advantages and limitations are listed. This part provides the theoretical basis for the next research of this thesis.(2) The corresponding optimization model is established by the finite element software ANSYS, the principle is introduced to determine the reasonable bridge state of multi-pylon cable-stayed bridge, the cable force of Jiashao River-Spanning Bridge is optimized by using a method based on influence matrix, and the concrete implementation process is introduced. The results show that it is feasible to use influence matrix method to determine the rational cable force in finished stage for multi-pylon cable-stayed bridge with a large number of cables and significant spatial effect. Beside, using this method can get the satisfactory results quickly.(3) The implementation process, which has been used to determine the reasonable construction state of Jiashao River-Crossing Bridge by using the unstressed state control method, is introduced in detail. The results show that it can obtain satisfied results with only one step calculation, when calculate and analysis the construction process of steel box girder cable-stayed bridge by using unstressed state control method. Therefore, the method used in this article is feasible for the reasonable construction state determination, and has many advantages such as efficiency and simple.