Analysis Of Structure Parameters And The Main Girder Mechanical Characteristics For Extradosed Cable-stayed Bridges

Extradosed cable-stayed bridge is a new bridge-type between continuous bridge and cable-stayed bridge.It possesses the characteristics both of each other, which makes its superior performance. Recently, it shows great development potential home and abroad. In terms of its structure, the main beam, cables and the main tower work together to resist load. The cables shares part of the load, the main beam bears most of the load, so the stress state of extradosed cable-stayed bridge is more complicated than general cable-stayed bridge and beam bridge. The phenomenon of stress uniformity is more serious, so it is essential to analyze structure parameters and the main girder mechanical characteristics for extradosed cable-stayed bridges.The cantilever construction method is usually adopted when extradosed cable-stayed bridge is built, this method exists many structure system conversion. This article is based on the construction of Shi Wan Extradosed Cable-stayed Bridge, using the Midas Civil software to establish the whole bridge model to simulate the whole construction process. The influence for main beam stress is considered under concrete shrinkage, creep, and temperature effect, the stress distribution regularities is obtained by the stress analysis under construction stage and finished stage for Shi Wan Extradosed Cable-stayed Bridge. The result shows that the most unfavorable phase is the maximum cantilever construction phase,the most unfavorable position is the root, and the phenomenon of stress concentration appears among the calculation. The structural system changes after closure. Overall force of main beam is uniformity. After secondary dead load, the stress begins to increase.In this paper the impact of the structure characteristic parameters. for girder force is discussed. Corresponding finite element models are established by simulating different boundary conditions, different tower heights and different non-cable-stayed lengths. Then, the stress distribution regularities of main beam under different parameters are got by calculating force and deformation for structure. The result shows that cable-force of hinged connection is higher than that of rigid connection, and the distortion of rigid connection is small. As the ratio of tower and span increases, the cable-force decreases, meanwhile, the stress of the main girder and distortion increases, the steel volumes increase, these influences should be considered. As the length of non-stayed cable segment increases, the cable-force and the deflection crease at the same time. The stress change of main girder is complex, which makes all these factors should be taken into consideration.