基于区间模型的混凝土碳化耐久性非概率可靠度评估

Reliability assessment of non-probabilistic for concrete carbonation durability based on interval model and interval analysis

针对碳化耐久性概率可靠性评估需大量统计样本、实施中较为困难的问题,基于区间模型建立了钢筋混凝土碳化耐久性非概率可靠性评估模型,采用示例通过与规范中表达式结果对比,初步验证了所建模型及方法的有效性。基于碳化试验,发现概率与非概率可靠度指标临界值分别取1.25和1.0时,二者具有相同的碳化耐久期限。在相同计算精度条件下,与概率可靠性评估相比,非概率可靠性评估不确定参数取值易于确定,实用性强。进一步通过对不确定参数的区间特性进行灵敏度分析,发现与温度和湿度相比,保护层厚度的区间特征对钢筋混凝土结构碳化耐久年限影响最为明显。建议在钢筋混凝土结构所处环境人为无法干预的状况下,施工中严控保护层厚度可以有效提升结构碳化耐久年限。

In the light of the problem that a large number of statistical samples are required for the probabilistic reliability assessment of carbonation durability and these statistical samples are difficult to search for determination of parameters,non-probabilistic reliability assessment model for reinforced concrete carbonation durability based on interval model,the comparison between the results of the calculation and the formula in the specification shows that the model and the method is significant.Based on the carbonation test,it find that there are the same durability period when the probabilistic reliability index and non-probabilistic reliability index are 1.25 and 1.0 compared with the probability reliability assessment,the value of uncertain parameters in the non-probabilistic reliability assessment method are easier to determined and more fairly practical in the same conditions of calculation precision.Through uncertain parameters′sensitivity analysis of interval characteristics,it is found that compared with interval characteristics of temperature and humidity,the protective layer thickness have most obvious influence on the carbonation durability of reinforced concrete structures.