地震荷载作用下相关性对结构可靠度的影响

Effect of dependence on structural reliability for earthquake loading

当一个结构系统承受偶发的不确定地震荷载时，其结构单元或元素失效的相关性在系统可靠度评估中的作用十分重要。该相关性的产生，是由于结构系统同时受某一基本随机变量的影响，如地震峰值地面加速度、荷载效应转换或构件承载力等。本文分析了考虑该相关的必要性。此外，还给出了一个考虑相关性的简单方法，可用于估计一个等关联性和等可靠度单元的并联系统的失效概率。该方法由拉普拉斯渐进逼近积分法导出。

When a structural system is subjected to an infrequent uncertain seismic load, the dependence among the failures of structural components or elements plays an important role in the reliability assessment. The importance of taking the dependence into account is assessed based on the uncertainty in basic random variables such as the peak ground acceleration, transformation from load to load effects, and member resistance. Also, a simple to use approximation by considering such a dependence is given for estimating the probability of failure of an equicorrelated and equireliable parallel system. The approximation is derived using asymptotic approximations to integrals of Laplace type.