Fire Protection of Steel Bridges and the Case of the MacArthur Maze Fire Collapse

Abstract

Both steel and reinforced concrete bridges are vulnerable to fire caused by a multitude of events such as tanker truck accidents, wildfires, arson or terrorism. This paper addresses bridges with steel super-structure and steel reinforced concrete or composite piers. After a brief summary of fire effects on bridges, the paper discusses the fire-induced collapse of two spans of the MacArthur Maze, a steel elevated freeway in Oakland, California. The two spans collapsed on April 29th, 2007 due to a fire caused by a tanker truck that overturned on the bridge. This paper discusses solutions and technologies that can mitigate the fire hazard in steel bridges. Based on the field investigation and analysis of collected data as well as fire analysis results, the following conclusions were reached: (1) the collapse could be prevented if the bridge was studies for the fire risk which would have led to recognition of high fire hazard at this intersection and vulnerability of the exposed steel girders,(2) the steel bridges and overpasses can be fire-protected using a variety of technologies and products successfully used in buildings; and (3) the current analytical tools could predict the time of the collapse accurately.