Simplified LRFD Design of Steel Members for Fire

This paper proposes a simplified design methodology for steel members under fire in accordance with LRFD provisions. The fire design criterion compares the required design strength ratio with the design strength reduction ratio. Design strength ratios are derived from the required strength factor and the overstrength factor. Simplified formulas for member strength at elevated temperatures, as well as their corresponding critical temperatures, are derived for steel members under tension, compression and flexure, for unrestrained boundary conditions. An illustrative example is presented and comparisons are made with experimental data.