Year 1, 2 report Data

Extreme fire events in tunnels may have catastrophic consequences, which include loss of life, structural damage, and major socioeconomic impacts due to service disruptions. In this report, a traveling fire model for a railway tunnel is established to evaluate the evolution of temperatures considering fire spread between train cars. Uncertainties in the amount of fuel, ventilation velocity, tunnel slope, ignition point, and criteria for fire spread are incorporated to capture distributions of fire temperature and duration in the tunnel. The generated demand fire scenarios are used to quantify the potential damage to a concrete tunnel lining in terms of the volume of concrete that would require replacement after a fire event. A finite element modeling approach is developed to incorporate the effects of concrete spalling on the structural response. Further, realistic soil conditions and overburden pressures are modelled and verified using soil-specific simulation software and analytical solutions. The evolution of moments during the heating and cooling phases of a fire are modelled and the results demonstrate the importance of capturing the cooling phase during both simulation and experimental testing. Small-scale element testing of concrete spalling is performed at the New Jersey Institute of Technology, which considers concrete mixtures with polypropylene (PP) and steel fibers, and demonstrates the effectiveness of the PP fibers. Four large-scale concrete slabs are tested using the large furnace at the University at Buffalo. Three test specimens contain fiber reinforcement, which prevented spalling during testing. The last specimen did not contain fibers, and the specimen experienced significant spalling during the heating phase. Evolution of temperature within the cross section, displacements of the four concrete slabs, and damage in terms of cracking, spalling, and reduced strength are reported. The outcomes of this report provide insight on the likelihood of fire damage to the concrete liner of railway tunnels.