Theoretical Framework for Robustness Evaluation

This paper presents a theoretical framework for evaluation of robustness of structural systems, incl. bridges and buildings. Typically modern structural design codes require that ‘the consequence of damages to structures should not be disproportional to the causes of the damages’. However, although the importance of robustness for structural design is widely recognized the code requirements are not specified in detail, which makes the practical use difficult. This paper describes a theoretical and risk based framework to form the basis for quantification of robustness and for pre-normative guidelines. This includes different measures to quantify the level of robustness taking into account the reliability of the structural system and the consequences of failure. The robustness measures are: 1) risk-based, 2) reliability-based and 3) deterministic.