Structural safety-issues and progress

摘要

A major aspect of ensuring safe structures is the management of uncertainty. The nature of safety, risk and uncertainty is discussed. Three types of uncertainty are considered: aleatoric, epistemic and ontological. The first is readily described in terms of probability distributions, so within this type of uncertainty, safety involves achieving less than a particular failure probability. The second cannot so easily be described by probability distributions, though the uncertainty can be estimated. The third type of uncertainty is essentially unknown. The different kinds of uncertainty call for different strategies. Probabilistic structural analysis deals with aleatoric uncertainty and to some extent epistemic uncertainty. Ontological uncertainty requires different strategies such as quality assurance or indicator methods. In addition, the traditional narrow focus on structural analysis is now broadening to include economic analysis and the social and environmental context of safety. This requires a different way of looking at safety. There is a shift from a narrow technical focus to the broader systemic viewpoint required for modern problems. The paper ends with a summary of problems needing to be addressed.