Assessment of the robustness of structures subjected to fire followingearthquake through a performance-based approach

The analysis of the behaviour of structures under the effect of fires following an earthquake is a significant research field, which is not yet fully explored. The high probability of occurrence of fires in civil and industrial buildings after being struck by a seismic shake justifies the need to investigate the response to high temperatures of the structural systems, they being already in a state of irreversible deformed configuration due to earthquake. In order to preliminary take into account in the design phases the effect of the combination of the seism and fire accidental loads, the paper presents a proposal for a methodology aimed at the robustness assessment under fire of structures already damaged to different extent by the earthquake, through a performance-based approach. The procedure should be valuable as a design tool in all seismic prone area, as it is envisaged for buildings of high strategic importance. In this paper the methodology will be exemplified with reference to steel structures.