Basis of the Analysis and Design for Fire-Induced Collapses in Structures

This paper will present some simple ideas which form, in the authors' experience, the basis for dealing with structural design and analysis in case of fire actions. To this aim, the following aspects are discussed: 1) the characteristics of high probability-low consequences (HPLC) versus low probability-high consequences (LPHC) events; 2) the systemic nature of fire accidents; 3) the concept of risk and the related activities, as risk analysis, risk assessment, and risk management; 4) the identification and development of fire scenarios. Specific attention is devoted to the interactions among the different aspects that need to be modelled, which are fire development, heat transfer, structural response and human behaviour. In the last part, some considerations are developed considering the case of a tall building subjected to fire and few critical results of the structural analysis are discussed.