Underground concrete frame structures subjected to fire loading: Part I – Large-scale fire tests

Fire events in enclosures (such as tunnels) can have severe influence on the safety of support structures, characterized by severe fire loading as regards both the speed of temperature rise and maximum temperatures. This paper contains results of real-scale fire tests, comprising temperatures within the tested concrete cross-section, deformations and rotations at various locations as well as the extent of spalling. Monitoring of cracks during and after fire loading completes the experimentally-obtained data. Based on the collected data, validation of numerical tools for the assessment of the safety of underground support structures, as presented in Part II of this paper, becomes possible.