The Analysis And Numerical Simulation Study On Large-Span Prestressed Concrete Cable-Stayed Brdige

The cable-stayed bridge is an indeterminate structure with high degrees, and the structure analysis of the cable-stayed bridge is complicated. Construction method is closely related to the internal forces and deformation of the bridge. During construction course, in order to keep the bridge safe and the deformation of the bridge reasonable, the construction control of large-span prestressed concrete cable-stayed bridges becomes an important research subject. The accurate model should be constructed and the effective structural analysis method should be taken to analyze and study the structural behavior in the construction stage and service stage of cable-stayed bridges.The thesis, taking the Yongjiang Bridge on the highway around Ningbo city as background example, establishes a spatial finite element model by using large scale finite element analysis software Midas/Civil, and analyzes the structure behavior, based on the fininte element theory of bridge.Determining the reasonable design state is the precondition of the design and computing of the cable-stayed bridge. Firstly, the reasonable design state of Yongjiang Bridge is determined by the minimum bending energy method, and some unreasonable cable forces are optimized and adjusted. The results show that the method is effective.Secondly, the model simulating the construction process is established according to the actural construction process, and the initial cable force in construction stage is determined by using forward method, which is a simple method to use by simulating forward construction process. The initial forces of cables gained by the forwarding method may approach reasonable forces easily and ensure the shape of structure.Thirdly,.the thesis studies the structure behaviors in construction process of the bridge, and various effects, including dead load, concrete creep and shrinkage, prestressing forces etc., on the structure behavior are considered. Through the analysis on the deformation of the bridge, the theoretical values of elevation of main beam segments are gained, which are the targets of construction control. The analysis of stress and deformation shows that the bridge is safe in construction stage, and that the strength is enough, the deformation is reasonable.Finally, the thesis studies the structure behaviors of the bridge in service stage under various condictions. In a word, this thesis helps me deeply understand the structure behaviors of cable-stayed bridges, and the method to compute and analyze large-span concrete cable-stayed bridges can be learned. Meanwhile, this thesis may be helpful for the construction and design of large-span prestressed concrete cable-stayed bridges.