Abstract

The search for a bona fide robustness index to quantify the system performance upon unexpected disturbances has been a continuous research effort. Previous studies have largely neglected to reflect the damage evolution feature of a progressive collapse failure. To bridge this important knowledge gap, this paper presents a novel risk-based robustness index for structures prone to disproportionate progressive collapse. Defined on a new concept, referred to as damage evolution curve, the proposed index considers the full spectrum of risk due to initiating events, and rigorously quantifies the impact of intermediate partial damages on the robustness assessment. Examples using a Daniels system, a truss, and an idealised moment-resistant frame are presented to illustrate how the proposed index is applied for assessing the robustness of structures with increasing complexity. In addition, a comprehensive comparative study against four existing robustness indices is carried out. It is shown that the proposed index provides consistent results for different influencing factors, whereas the other indices either respond counter-intuitively or are insensitive to some of the factors. With consideration of intermediate damage and failure consequences, the development of the proposed robustness index represents an important step towards the performance-based design against progressive collapse.

摘要

寻找一个真诚的人用于量化系统在意外干扰下的性能的鲁棒性指数一直是一项持续的研究工作。以前的研究在很大程度上忽略了反映渐进式倒塌破坏的损伤演变特征。为了弥合这一重要的知识鸿沟，本文提出了一种新的基于风险的稳健性指数，用于容易发生不成比例的渐进式倒塌的结构。提出的指标定义在一个新的概念上，称为损伤演化曲线，考虑了由始发事件引起的全方位风险，并严格量化了中间部分损伤对稳健性评估的影响。给出了使用 Daniels 系统、桁架和理想化抗弯框架的示例，以说明如何应用所提出的指数来评估复杂性不断增加的结构的稳健性。此外，还对四个现有的稳健性指数进行了全面的比较研究。结果表明，所提出的指数为不同的影响因素提供了一致的结果，而其他指数要么反应反直觉，要么对某些因素不敏感。考虑到中间损坏和失效后果，提出的稳健性指数的发展代表了朝着基于性能的设计抗渐进式坍塌迈出的重要一步。