Progress over the last decade on how fire affects the structural behavior of tunnel linings

Tunnel fires are relatively rare, but the consequences of damage can be large. This paper addresses the influence of tunnel fires on the ensuing damage to the concrete lining. To address this question, the existing literature is reviewed. This review focuses on different methodologies to get a well-rounded insight into the problem: relevant aspects of tunnel fire dynamics, theoretical considerations on the relation between the fire source and the resulting damage to the concrete, experimental evidences from testing concrete elements subjected to fire as well as data from tunnel fires that have taken place in the past, and insights from numerical analysis. The result is a comprehensive overview of what is currently known about the relation between a tunnel fire and the ensuing damage in the concrete, as well as guidance for the assessment of concrete tunnel linings under fire hazard and recommendations for future research to address the remaining open questions on this topic. To conclude, this paper gives a valuable overview based on different methodologies from the literature to give researchers, engineers, and asset owners a better insight in how fires can affect the concrete tunnel structure. • The link between fire source and ensuing damage to a concrete tunnel lining is clearly explained. • The combined effect of spalling, reduction of material properties, and thermal-induced deformations is discussed. • Ample experimental, numerical, and real fire cases’ evidence is provided. • An assessment strategy for tunnel lining under fire loading is developed. • Research needs to complement the assessment strategy are highlighted.