Stochastic Analysis Of Long-term Time Varying Effect Of Concrete Filled Steel Tube Stiffened Skeleton Arch Bridge

With the rapid development of bridge technology,the analysis and control of long-term effects of shrinkage and creep on high-speed railway bridges have been put forward with higher and higher requirements.However,due to all the discretization of concrete shrinkage and creep effect calculation model,the randomness of parameters,the uncertainty of measurement and other reasons,both the calculation of concrete shrinkage and creep effect and its structural effect have a great discreteness.The deterministic analysis of structures cannot satisfy the need of practice nowadays.In this thesis,the long-term effects of shrinkage and creep of concrete filled steel tube stiffened skeleton arch bridge are randomly analyzed based on the newly built Meixi River bridge on high-speed railway from Zhengzhou to Wanzhou.The following is the main content:(1)By consulting a large number of literatures,the main development model and calculation theory of concrete shrinkage and creep are briefly described.The random factors affecting the randomness of structural effects and their distribution characteristics are determined.(2)The stochastic analysis theory of structural shrinkage and creep is briefly reviewed.The Monte Carlo method based on response surface and the Monte Carlo method based on artificial neural network(ANN-MC)are emphatically introduced.(3)The accuracy of Monte Carlo method based on artificial neural network(ANN-MC)for stochastic analysis of shrinkage and creep effects of concrete is verified from two aspects.The results show that Monte Carlo method based on artificial neural network(ANN-MC)has a good performance in stochastic analysis of structural shrinkage and creep effect.(4)According to the Monte Carlo method based on artificial neural network(ANN-MC)and considering eight random factors,the long-term time-varying randomness of the structure is analyzed on the basis of Meixi River Bridge on Zhengzhou-Wanzhou high-speed railway.The results show that the long-term displacement,steel tube stress and stress of concrete filled in the steel tube for the structure are highly random after considering the effect of eight random factors,while the external concrete stress fluctuates less.