Research On Pre-stress Cable-stayed Bridge With Ground Anchor In Rational Complete And Its Cable Force Control

The superstructures of cable-stayed bridge mainly include three parts:tower, main girder and stay cable. As the structure that connects tower and main girder, cable's main function is to pass the load, which come from dead load and vehicle loads, to towers and towers finally pass the load to the base. Cable-stayed bridge is a high degree statically indeterminate structure, whether or not the cable force is reasonable decides the safety and internal force distribution of cable-stayed bridge directly. Thus, a reasonable cable force control could make the process of building or reinforcement faster, simpler and safer. Based on the reinforcement of Hubei Yunyang Hanjiang Bridge, finite element analysis program MIDAS/CIVIL is used to simulate, analyze and calculate it. This paper focuses on the control of cable force. Main jobs of this paper are as following:(1)Simply introduced and summarized the calculating and optimizing methods of stay cable force. By comparing their advantages and finding out their disadvantages, one way should be chosen to complete the calculation when the controlling object function is decided.(2)Cable force control methods are introduced.By comparing the advantages and disadvantages of method of once tensioning, which based on the theory of backward analysis, and method of multi-time tensioning, which based on the theory of forward analysis, method of two-time tensioning are developed.(3)Discussed the influences of no-linear factors which exist in the process of calculating the final cable force and how to deal with them in simulating.(4)Briefly introduced the methods of cable force measuring and mainly described the frequency method, which applied in the program of reinforcement frequently. Also, to get more precise value, elimination method is applied to eliminate the affection of bending rigidity.