Structural Optimization Of Extradosed Cable-Stayed Bridge With Steel And Concrete Composite Beams

Extradosed cable-stayed bridges are hybrid structures, whose mechanic characteristic lies between continuous beam bridges and cable-stayed bridges. In recent yearsf extradosed cable-stayed bridges have rapidly developed in the foreign and domestic because of its economy and beauty. Steel-concrete composite beam was widely used in cable-stayed bridges but in the extradosed cable-stayed bridges. The paper tries to simulate the working estate of steel-concrete composite beam in the extradosed cable-stayed bridge through finite element method and MIDAS software. By optimizing the cable, the length of non-cable area and the tall of girder exert the speciality of steel-concrete composite beam, getting the purpose of optimizing of extradosed cable-stayed bridge with steel-concrete composite beam. The main contents that this paper study is as follows:1. In this paper, it is used that the configuration of "Xiao Xi Hu Ai Ta Xie La Qiao" and the girder of’"Qing Zhou Min Jing Da Qiao" as the original model. By which adopting finite element method and making use of MIDAS finite element method,the model of extradosed cable-stayed bridge with steel-concrete composite beam is built.2. Built the matrix of cable’s strength of extradosed cable-stayed bridge. Aim at strength of cable and moment and displacement, optimizing the strength of cable of extradosed cable-stayed bridge in order to fit the necessary of girder.3. Modulate the length of non-cable area and built the model which is corresponded to. Comparing the changes of moment of different models in different length of cable. Summing up the changing rules. Get the range of length of non-cable area in steel-concrete composite beam.4. Choosing the different height of tower, built the proper model. Get the target of optimizing the tower’s height through the method of optimizing of cable strength. Increasing the strength of cable in average of20%and lower the height of tower to12m. Lower the difficultness of real project,shorten the time limit and save the chargeIn this paper,the research of optimizing of extradosed cable-stayed bridge will give some reference to the using of steel-concrete composite beam in this kind of bridge and accelerate the development of extradosed cable-stayed bridge with steel-concrete composite beam.