基于初始缺陷的混凝土锈裂模型时变可靠度

Time-Varying Reliability of Rust Cracking Model Based on Initial Defect

根据断裂力学理论,建立了考虑初始缺陷的混凝土结构锈胀时间预测模型,以此为基础建立了结构寿命预测极限状态函数,并发展了基于三阶矩法的时变可靠度分析方法.研究结果表明:与Monte-Carlo方法对比,在计算结果较为吻合的情况下,本文方法减少了计算次数,提高了分析效率;在混凝土材料参数中,混凝土结构失效概率对保护层厚度的随机性和不确定性最为敏感,失效概率对随机变量概率分布类型敏感性较差.

In this paper,the prediction model of rust expansion time of concrete structures with the consideration of initial defects is established based on the theory of fracture mechanics.The limit state function of structure life prediction is established and an analysis method of time-dependent reliability based on three-order moment method is developed.The results show that compared with Monte-Carlo method,this method reduces the calculation time and improves the analysis efficiency when the calculated results are more consistent with each other.Among the parameters of concrete materials,the failure probability of concrete structure is the most sensitive to the randomness and uncertainty of cover thickness and less sensitive to the probability distribution type of random variables.