The Fire Resistance of R.C. Tunnels: New Design and Verification Challenges

The basis of a possible design and verification approach to the linings of RC tunnels in fire is presented and discussed. Five damage states are identified for the linings, based on the consequences of several real fires occurred in the past. Back analyses are carried out to define the main parameters controlling each damage state, whose temperature range is determined via fluid-dynamic analyses based on fire zone models and Computational Fluid Dynamic Modelling to identify temperature value ranges for the different damage states. Finally, the proposed approach appears to be appropriate for the in-fire analysis of both railway/road tunnels and underground infrastructures for complex researches.