Structural behavior of simple steel structures with non-uniform longitudinal temperature distributions under fire conditions

Abstract

The paper focuses on the effects of longitudinally non-uniform temperature distributions on structural fire response up to failure of thermally protected steel structures, composed of beams and columns in simple frame situations. The evolution of non-uniform longitudinal temperature distributions stems from the inherent continuity of the construction and was addressed in a previous paper. Structural analysis was accomplished by the existing program SAFIR. Stand-alone beams and columns, as well as simple frames were analyzed. Results demonstrate that the longitudinal non-uniform temperature distributions affect the patterns of structural behavior, causing a shift and delay in the formation of plastic hinges, and resulting in an increased period of structural stability. It is demonstrated that this increase is larger than that associated with using advanced tools for structural analysis. However, the improvement of the apparent fire resistance of beams is usually larger than that of columns.