Comprehensive Optimization Of Pc Cable-stayed Bridge Cable Stayed Area, Cable Tension, And Prestressing Tendons

In the design process of PC Cable-stayed Bridge,the relationship among the selection of stay-cables area, the adjustment of cable force and the usage of prestressed tendons in girders is interactional and coupled which decides the whole bridge's internal state and economic performance.Only after repeated adjustment and calculation can we get a better solution in the design process of large-span Cable-stayed Bridge, it's time-consuming and cumbersome.And the design solution depends on the designer's level.It's one of the difficulties of PC Cable-stayed Bridge design.Scholars both at home and abroad have done lots of researches and got satisfactory effect on how to decide finished dead state of bridge. But there is no precedent at home and abroad about taking the stay-cables area as variable into the whole optimization.This paper includes research achievements from former researchers, and also has completed the following work:1. Development situation of PC Cable-stayed Bridge, summarize and compare the features of methods of determining the finished dead state of bridge;2. This paper puts forward and develops optimization mathematical model on the basic of comprehensive consideration of cable force,cable area and prestressed tendon area and it takes both the finished dead state of bridge and economy into consideration;3. Expatiate on the Generalized Reduced Gradient Method used in the paper, reconstruct and expand the original program GRG-C, and verify the correctness and effectiveness of the program by example checking;4. Proceed the structure reanalysis of optimization process by the method of influence matrix which is time-saving and high-efficient;5. Compile the FORTRAN program on the basic of the optimization model,carry out the optimization calculation and stress checkup on a typical long-span PC Cable-stayed Bridge,the results show that after optimization the stresses in beam,tower and cable are more reasonable,and the total cost of prestressed tendons and cable is lower. And this states the effectiveness of the paper's method.