Vulnerability assessment of major urban tunnel subjected to fire induced by traffic incidents - a case study

Abstract As a type of critical transportation infrastructures, safety of major tunnels in urban transportation corridors has become unprecedentedly crucial. In various fire incidents with high temperature environment, the ceiling and wall of a tunnel would risk spalling, strength reduction, and even structural failure. In addition to risks of structural damage, high temperature and thick smoke in fire incidents will increase the risk of severe injury and even death due to burning, lack of oxygen, inhaling smoke and reduced visibility for people inside the tunnel. Limited mobility of evacuees would delay the evacuation process by endangering the safety of both evacuees and first responders. A comprehensive simulation-based case study is conducted to look into the fire and smoke simulation as well as potential threats to structural integrity and human health caused by fire in typical traffic incidents of three types of vehicles. Fire and smoke simulation are conducted using the Fire Dynamics Simulator (FDS), followed by the thermal and structural analyses with ANSYS. The comprehensive parametric study provides insights in terms of the impacts of different parameters including various typical traffic fire incidents on the structural performance and potential threats to evacuees.