The theory of structural robustness has only recently emerged in the field of structural civil engineering, as a consequence of both minor and major collapses, one of which being the World Trade Centre terrorist attack (New York, 11th September 2001). Normally, buildings are designed to withstand normal actions, whose types and intensities are defined according to the building’s importance. In reality, structures are not always able to withstand exceptional events, such as impacts, explosions, and fires; these scenarios have a low probability of occurring, but can have catastrophic results in terms of loss of life, environmental and economic damage, as well as disruptions to public utility services.