Characterisation of the fire decay phase and its effects on structural elements


  • Andrea Lucherini
  • Balša Jovanović
  • Bart Merci (supervisor)
  • Ruben Van Coile (supervisor)


Modern societies should ensure that load-bearing structures are designed to maintain their stability and integrity until complete fuel burnout. This represents a core aspect of the fire safety strategy and enables the safe evacuation of the building occupants and fire brigade intervention. Also, a robust fire-safe design can limit the potential catastrophic socio-economic consequences of a fire, reducing the disruption of critical infrastructures and facilitating the post-fire rehabilitation. Consequently, design approaches should focus on analysing the structural behaviour of load-bearing systems during all the typical phases of a natural fire in an enclosure: growing, fully-developed and decay. The fire decay phase is typically largely simplified, for example by assuming linear cooling rates. However, delayed failure can occur during or after the fire decay phase, as demonstrated by the Gretzenbach car park collapse (Switzerland, 2004) which caused 7 firefighters casualties. The main aim of this research project is to understand the impact of the fire decay phase on fire-exposed structural elements and propose engineering tools to promote performance-based design methodologies for fire-safe structures. Different engineering approaches and experimental results are first employed to characterise the fire dynamics during the fire decay phase within a certain enclosure, with varying compartment and fuel characteristics. The obtained thermal exposures are then implemented in numerical methods to analyse the performance of typical structural elements exposed to fire. The parameters governing the fire decay phase are examined and their influence on the structural integrity is quantified.

Graphical abstract Andrea Lucherini