水工钢闸门主梁失效模式间相关性分析  

Evaluation of correlation between multiple failure modes for main girders of hydraulic gates

作　　者：吴帅兵[1] 李典庆[1] 唐小松[1] 

机构地区：[1]武汉大学水资源与水电工程科学国家重点实验室,湖北武汉430072

出　　处：《武汉大学学报（工学版）》2009年第3期317-321,325,共6页Engineering Journal of Wuhan University

基　　金：国家自然科学基金项目(编号:50609016);高等学校全国优秀博士学位论文作者专项资金项目(编号:2007B50);水利部水工程安全与病害防治工程技术研究中心开放基金(编号:S0701)

摘　　要：分析了主梁受弯、受剪和弯剪复合破坏3种主要的失效模式.推导了不同失效模式中含有不完全独立亦不完全相关的随机变量时失效模式间相关系数的计算公式.采用JC法计算了主梁不同失效模式的可靠指标及其敏感性因子.在此基础上,采用Ditlevsen窄界限公式计算了水工钢闸门主梁的体系可靠指标.结果表明所提出的失效模式间相关系数计算公式更具有一般性,它既可以考虑不同失效模式中含有相同随机变量时的相关性,也可以分析不同失效模式间包含相关随机变量的相关性.该公式为Ditlevsen窄界限公式计算结构体系可靠度提供了有益的补充.如果忽略了失效模式间的相关性,水工钢闸门主梁的体系可靠度水平将会被低估.Ditlevsen窄界限公式计算的主梁体系可靠度范围非常小,它完全可以满足一般情况下主梁体系可靠度计算精度的要求.Three failure modes of main girders of hydraulic gates, namely bending failure, shear failure, and combination of bending and shear failure, are discussed. Formulae of correlation coefficients between different failure modes including different correlated random variables are derived. JC method is employed to calculate the reliability indexes and sensitivity coefficients for different failure modes of main girders. The formula for lower and upper bounds of system reliability proposed by Ditlevsen is adopted to perform the system reliability analysis of main girders with multiple correlated failure modes. The results indicate that the proposed formulae of correlation coefficients between different failure modes can consider the correlated failure modes including different correlated random variables effectively, which can facilitate the system reliability evaluation using the Ditlevsen formula. If the correlations between different failure modes are not taken into account, the system reliability level of main girders will be underestimated. The Ditlevsen formula can obtain very narrow bounds of system reliability for main girders.

关 键 词：平面钢闸门 主梁 多失效模式 体系可靠度 相关系数 

分 类 号：TV311.2[水利工程—水工结构工程]