ABSTRACT
In the 1990s, ventilation systems were extensively tested by the Massachusetts Highway Department at Memorial Tunnel in West Virginia. Test data on released smoke and heat influenced the design of the tunnel ventilation program on Boston’s massive Central Artery/Tunnel project (Massachusetts Highway Department 1995, Robena 1995). The focus of these tests, however, was on human safety, not structural safety or stability. Moreover, the tunnel structural members were heavily insulated so as to incur no damage during the 98 short duration tests (from 15 minutes to 30 minutes). The Memorial Tunnel in West Virginia was also utilized to simulate the Howard Street Tunnel Fire of Baltimore (McGrattan & Hamins 2003)
1.2 Tunnel fire rating curves
Tunnel fires are rare events and cannot be classified as service loads in structural design. For structural analysis or design check, different fire rating curves are developed for tunnels representing extreme fire events. These curves are mainly used for structural fire rating (PIARC 1999), and are not a function of the size of the tunnel or ventilation system, or represent the burning of a single vehicle. Furthermore, it was observed by Takekuni et al. (2003) that the smallsize tunnels have higher temperature readings on tunnel liners than the large-size tunnels when subjected to the same type of fire.
