Analysis Of Shrinkage And Creep Effect Of Long-Span Concrete Arch Bridge With CFST Stiffening Frame

The rigid skeleton construction method solves the problem of self-erection in the construction of long-span arch bridges and is widely used in the construction of long-span arch bridges.However,it causes complex shrinkage and creep effects of the concrete arch bridge with CFST stiffening frame.Therefore,it is of great significance to study the shrinkage and creep response of the concrete arch bridge with CFST stiffening frame.At present,the popular shrinkage and creep model can not accurately reflect the shrinkage and creep phenomena of concrete.Therefore,this thesis adopts reliability theory,regards the main factors affecting shrinkage and creep as random variables,and analyses the influence of shrinkage and creep effect on the concrete arch bridge with CFST stiffening frame from the perspective of probability.Taking Wushan Daning River Bridge on Zhengzhou-Wanzhou High-speed Railway as the engineering background,this thesis has done the following research work:1.Using Midas Civil software and CSBNLA finite element software,the beam-slab model and the spatial degraded beam model of Wushan Daning River bridge on ZhengzhouWanzhou high-speed railway are established respectively.The deformation of two different model in construction stage is compared,and the stress of the concrete arch bridge with CFST stiffening frame in construction stage and operation stage is analyzed.2.Using the degenerated beam model established by CSBNLA finite element software,the influence of material nonlinearity and geometric nonlinearity on the structural response of the concrete arch bridge with CFST stiffening frame is discussed.3.Based on the theory of response surface and FORM method,the random variables affecting the shrinkage and creep effects of concrete are introduced to calculate the reliability of the arch instability of concrete arch bridge with CFST stiffening frame and the sensitivity of random variables.