Recent developments in robustness and relation with risk

Structural engineering is a mature discipline, but in practice the nature of demands or actions on a structure remains uncertain. It is difficult to foresee where damage, for example resulting from an accident or material degradation, might occur. A structure that is robust will be able to cope with such unexpected demands without disproportionate consequences. There is, however, no satisfactory measure of robustness: not even a widely agreed definition. In this paper an overview of the current guidelines and methodologies to achieve a robust structure is provided. Most of the analytical studies assume a model of loading, but to achieve robustness there is a need to identify potential weaknesses in the form of a structure. In this respect, structural vulnerability theory can be an effective tool to reduce the risk of propagation of failure owing to unforeseen damage or actions. Similar models are already used in the insurance industry to determine the risk to natural and man-made hazards.