Integrity of Structural Steel After Exposure to Fire

Perceptions of fire vary depending on the circumstance to which the individual is exposed. Controlled fires are rarely given much thought in our daily experiences. Uncontrolled fires, with the specter of buildings collapsing, the implied damage, potential injury and loss of life have created a very negative image. A negative connotation often exists that anything exposed to fire and heated to a high temperature must be damaged, regardless of the appearance of the structural members. Exposure to fire will subject structural steel to thermally induced environmental conditions that may alter its properties. Assessing these altered properties requires a combined knowledge of metallurgical and structural behavior as the fire raises the steel temperature and the steel later cools. Knowledge of steel properties and behavior developed from basic steel production, thermal cutting, thermal or mechanical straightening (or curving), heat-treating and welding provides the requisite information.