Fire impact and passive fire protection of infrastructure: State of the Art

Built infrastructure in the United States is generally susceptible to damage or collapse if subjected to severe fire conditions, such as those associated with the burning of a fully loaded gasoline tanker truck. Because of the importance and heavy use of transportation systems within the United States, it is critical that susceptibilities to fire damage are investigated and mitigated to reduce the potential for substantial life-safety and economic losses. The need for infrastructure fire protection is heightened by the frequency of collapse of infrastructure components (e.g., bridge superstructures) as part of severe fire incidents. However, fire protection of infrastructure remains a developing area. Presented in this paper is the state of the art in passive fire protection of transportation structures. More specifically, the impacts of high-intensity fires on existing infrastructure and commonly used structural materials are reviewed. Additionally, design standards that provide means of assessing fire safety levels for passively protected transportation structures are reviewed, and the capabilities of existing fire protection materials available for use in transportation structures are assessed. Given the diverse nature of transportation structures located within the United States, this paper is organized such that state-of-the-art fire safety aspects are emphasized for two major types of transportation systems, namely, tunnels and bridges.