考虑空间变异性的在役钢筋混凝土梁桥失效概率评估

摘要

It was pointed out that the uncertainty and spatial variability are the core issues of RC material degradation. A probabilistic assessment method was proposed for existing RC bridges considering spatial variability. Correlation matrix was employed to quantify spatial variability. An efficient method was established to obtain the correlation matrix of material parameters from non-destructive testing data. The calculation method was deducted for resistance correlation and cell function-failure correlation. The main influence factor of existing RC structure resistance was studied by correlation analysis. The relationship between material parameter correlation and function-failure correlation was studied through sensitivity analysis. The results show that spatial variability has to be considered for probabilistic assessment of existing RC bridges, and steel bar corrosion ratio is the main influence factor of function-failure correlation. For structures with low reliability index ( β <4.0) , safety evaluation should adopt the failure probability.%钢筋混凝土材料退化的两个核心问题为不确定性和空间变异性,首先架构了考虑空间变异性的在役梁桥概率评估方法.采用相关矩阵方法量化空间变异度,建立由无损检测数据确定纵桥向各测区材料参数相关系数矩阵的实用方法,且给出抗力相关性与单元(测区)功能失效相关性的计算方法.通过相关性分析研究在役结构抗力的主要影响因素,通过敏感性分析研究材料参数相关性与功能失效相关性的关系.结果表明评估在役钢筋混凝土梁桥需要考虑空间变异性,钢筋锈蚀率是功能失效相关性的主要影响因素;对于低可靠指标的结构(β＜4.0),可靠指标不能灵敏地反映安全程度,建议直接采用失效概率来表达.