Study On Optimization Designon The Auxiliary And The Combined Sectionof Hybrid Girder Cable-stayed Bridge

With the completion of a large number of large-span bridges, our country is changing from a big country to a powerful country in bridge construction.If we really want to achieve the dream of becoming a powerful country in bridge construction, we must start from the basic research work on long-span bridges. The research on the auxiliary and the combined section of Hybrid Girder Cable-Stayed Bridge is a part.Auxiliary pier on long span Cable-Stayed Bridge can make a significant improvement in the internal force distribution of side span girder. Different number and location of the auxiliary pier make it difference on the degree of improvement on the girder’s internal force. The location of the combined section will determine the length of the girder with different materials and so determine the distribution of the girder’s dead weight and then significantly affect the distribution of girder’s internal force. There for, it has a great impact on the design of long span hybrid girder cable-stayed bridge and research value how to constitute the location of the auxiliary pier, the number of the auxiliary pier and the location of the combined section.In this paper, the engineering background is the Hong Shui River Bridge, and author establishesthe model and research the number of the auxiliary pier and the location of the combined section withtwo sorts of different finite element software Midas/Civil and ANSYS. The main research contents are as follows:(1)This paper analyzes the current common method to determine reasonable finished dead state of cable-stayed bridge and based on actual research needs, identifiesthe method adopted in this paper.(2)Based on the original design, this paper establishes the model of the Hongshui River Bridge using Midas/Civil and establishes a series of comparative model by modifying the position of the auxiliary pier, the number of auxiliary pier and the position of combined section. By comparing the stress situation of girder under the dead load and live load, drawing some valuable conclusions, providing the basis for the next design model for structural optimization.(3)This paper introduces the building process of the Hongshui River Bridge ANSYS model as well as some simplifications for the structural optimization design calculations.(4)Through statistics of over two hundred of cable-stayed bridges have been built, combining with some theoretical analysis, identifying the parameters of design variables to optimize the design of the Hongshui River Bridge. Based on the previous study, identifies a number of objective functions and converts multi-objective function into a unified objective function.(5)Three parameters(auxiliary pier position, auxiliary pier number and combined section position) of Hongshui River Bridge are optimized and the optimization results are analyzed to obtain the optimum design.