The Randomness Of Creep And Reliability Of Concrete Filled Steel Tubular Arch Bridge

Creep is an inherent characteristic of concrete that has important effect on concrete structures and more important effect on some complex structures. Therefore, the accurate prediction of concrete creep and its effect is very significant. For solving engineering problems, scholars from all over the world have established a number of concrete creep models on the basis of large number of experiments and theory analysis. However, as lack of consensus understanding on the complex mechanism of concrete creep, these models still cannot make an accurate prediction for concrete creep and its effects on structures. But there is a phenomenon that results from creep models are always waved around test results and this phenomenon has characteristics meeting to the rules of statistics theory. So, by using the reliability theory, the paper considers the creep as a random process, and regards the influential factors on the concrete creep as random variables. In the process of calculating creep effects on structures, there are two aspects needed to be considered. The first one is to get statistical characteristic of random variables including their mean value and coefficients of variation. In the paper, there are four influential factors which have important effects on the concrete creep, are i.e. Water-Cement Ratio, Cement Volume, Aggregate-Cement Ratio, as well as Temperature. By dealing with the series of data from Japanese laboratories, variation coefficients are regressed. The second is to get method for calculating the creep effects. By using finite element method, the paper builds up finite element model and uses Monte Carlo method and Latin Cube Sampling method for reducing sample amount to calculate the reliability of a concrete column considering the creep effect.At last, the paper analyzes the reliability of CFST arch bridge on the basis of creep stochastic research. According to the method above-mentioned, the paper builds up finite element model of YAJISHA Arch Bridge to investigate creep effect on the structural, and regards its arch middle span deflection and arch capacity as indexes to get influence causing by concrete creep. The calculation results reveal that reliability of CFST Arch Bridge is declining caused by concrete creep. Then the paper makes sensitivity analysis of creep random variables and some suggestions are proposed.