Effects of Random Occurrence of Brittle Failure on Seismic Reliability of Structural Systems

本文旨在探讨脆性破坏的随机发生对结构体系抗震可靠性的影响。本研究由以下两部分组成。随机脆性破坏对结构体系最大响应位移的影响。考虑构件延性不确定性的钢结构抗弯框架吸能能力的统计评估。在本研究的第一部分，得到了以下结果：-随着脆性破坏发生概率的增加，体系在动荷载作用下的可靠度降低。在脆性失效发生概率较低的范围内，系统可靠性的递减率更为敏感。-结构体系由敏感构件和非敏感构件组成。敏感构件对体系可靠度影响较大，非敏感构件不受影响。研究的第二部分结果如下。-本研究提出了一个评价钢框架抗弯构件吸能能力下限的常规指标。-安全极限吸收的能量对构件延性的敏感性远大于失效极限吸收的能量。

The purpose of this study is to discuss effects of random occurrence of brittle failure on seismic reliability of structural systems. The present study consists of the following two parts.1. Effects of random occurrence of brittle failure on maximum response displacement of structural systems.2. Statistical evaluation of energy absorption capacity of steel moment resisting frames considering uncertainties of member ductility.In the first part of this study, the following results are obtained.-System reliability under dynamic load decreases with increasing the occurrence probability of brittle failure. The decreasing rate of system reliability is more sensitive in the range of lower occurrence probability of brittle failure.-The structural system consists of both sensitive members and non-sensitive members. The sensitive member has large influence on system reliability, and non-sensitive member is not affectable.The results for the second part of this study are as follows.-This study proposes a conventional index for evaluating the lower limit of energy absorption capacity for the moment resisting steel frames.-The absorbed energy for safety limit is much sensitive to the member ductility than the absorbed energy for failure limit.