Performance Of Long-span Composite Girder Cable-stayed Bridge With Three-tower Under Shrinkage And Creep

Rencent years,steel-concrete composite girder was widely used owing to its light weight, high intensity and high rigidity. Erqi Yangtze River Bridge is composite girder cable-stayed bridge with three towers with the longest span in the world,which is connected with steel girder and concrete slab. Steel-concrete composite is made of two different materials.It will lead interaction force between steel and concrete, internal force redistribution and lots of additional deformation because of concrete shrinkage and creep.As the change of shrinkage and creep for concrete is with the time, lead huge differences in the effects caused by concrete at different ages. In order to prevent producing the deflection,variation of stresses and the prestress loss caused by the shrinkage and creep of concrete, many composite bridges placed the precast concrete panels for some time and then set up.It could provide reference for design and construction of same kind of bridge through studying the performance of composite girder cable-stayed bridge under the concrete shrinkage and creep at different ages.Taking Erqi Yangtze River Bridge as an example, establish dimensional finite element mode with the bridge professional software MIDAS/CIVIL; study the performance of composite girder cable-stayed bridge under concrete shrinkage and creep; based on the age-adjusted effective modulus method,analyse the deflection and stress changes of composite girder cable-stayed bridge with three-tower under the influence of shrinkage and creep at different ages. Specifically speaking, this paper has dealt with the following respects:1,Taking Erqi Yangtze River Bridge as an example, establish finite element mode with the bridge professional software MIDAS. It proved that the bridge design is suitable, the deflection of main girder,compressive stress of concrete members and lasso both meet regulatory requirements;2,Analyse the performance of composite girder cable-stayed bridge with three-tower under the influence of shrinkage and creep, the analytical results indicate that, concrete shrinkage and creep can not be ignored for the deflection of composite girder cable-stayed bridge with three towers, the deflection of main girders increased 7.6cm; the stress of concrete slab has little change under concrete shrinkage and creep,just decreased 1.0MPa;but significantly for steel girders as an 10.9MPa increase; give full consideration to concrete shrinkage and creep for 47.89% of total loss.3,Based on the age-adjusted effective modulus method,analyse the deflection and stress changes of composite girder cable-stayed bridge with three-tower under the influence of shrinkage and creep at different ages, the analytical results indicate that:the longer the age of concrete is,the smaller the deflection and the stress change on composite girder cable-stayed bridge with three-tower,however, this trend in the age of concrete up to 180 days has stabilized.