ABSTRACT
New and existing civil structures can be exposed during their life to extreme actions deriving from either artificial or natural risks not considered in the design phase. Such risks are earthquakes in non-seismic areas, unforeseeable fires, exceptional storms, heavy snow, explosions, terrorist attacks and so on. The capacity of structures to resist these actions is identified as “robustness”. In particular, the most common meaning of this word in the field of Structural Engineering is the capacity of structures to not suffer a damage disproportional to the action (exposure) which has generated it. This definition, incorporated within several codes, such as the new technical Italian one (M.D. 2008), is not accomplished by effective criteria either in measuring robustness or determining whether the robustness level of a system is acceptable.
