FIRE HAZARD IN TUNNELS: REVIEW, ASSESSMENT, AND MITIGATION STRATEGIES

Fire in a tunnel is a rare probability, but it represents a severe hazard to the tunnel structure and can lead to significant loss of life, property damage, and traffic disruptions. At present, tunnel design codes and standards, unlike building codes, do not provide specific fire resistance provisions for the design of tunnel structure. However, the fire incidents in the last few decades have opened a debate on the need for fire resistance provisions to structural members in tunnels. This paper presents an overview of fire hazard in tunnels. The magnitude of fire hazard in tunnels is highlighted through tunnel fire incidents in the past few decades. The fire scenario in tunnel is characterized and the factors influencing the performance of tunnels under fire conditions are presented. Various strategies for mitigating fire hazard in tunnels are outlined. Further, a strategy to undertake post-fire assessment of tunnels is outlined. Finally, Knowledge gaps relating to fire problem in tunnels, together with research needs for enhancing the fire safety in tunnels, are discussed.