Probabilistic interpretation of robustness for structural systems

Authors

Marc A. Maes and Michael H. Faber

Abstract

The term robustness is used rather loosely in the context of structural engineering. Some consider it to be synonymous to redundancy and reserve system capacity, others consider it to be the opposite of vulnerability (which it self is also subject to various interpretations) to specific hazards, and yet others point out that robustness is critically related to the chain of consequences and decisions triggered by changes or deviations of the system characteristics. In this paper, we identify and examine the essential attributes of a robustness analysis: the careful system definition, definition of a set of desirable system characteristics and risk analysis taking into account all consequences. In the context of systems subject to exceptional hazards, the uncertainty associated with systems, hazards and consequences plays a prominent role and therefore indicators of robustness must express probabilistically the system performance subject to external disturbances. We review, propose, and validate risk based measures that can serve as indicators of the robustness of critical structural systems. The frameworks presented here for measuring robustness are widely applicable and implications for system modelling and acceptable levels of robustness are discussed. Robustness is interpreted here as damage tolerance, but the assessment procedure can be broadened to consider other aspects of robustness such as tolerance to human error in design or construction.

Published in/by

Proceedings PSAM8, International Conference on Probabilistic Safety Assessment and Management, New Orleans, USA, May 14-19, 2006, Paper 0324.