Experimental study and analysis on the collapse behavior of an interior column in a steel structure under local fire

This article describes the experimental and analytical results of tests on two medium-scale steel frames to investigate the collapse behavior of a heated interior column in steel-framed structures and the fire-induced collapse mechanism of the structures. Because the heated column in the structure was under realistic inelastic end constraints (inelastic effects from the surrounding cool structures) as opposed to an idealized column in a furnace, the tests were designed to investigate the effect of inelastic end constraints and different load ratios. The interior column subjected to fire in the first story was connected with a force-measuring bearing, which was developed to measure the axial force in the heated column. This article presents the observations and analysis results of structural fire behavior, including the temperature distribution of the column, the development of deflection and axial forces, and the column failure modes. The results show that the effect of realistic inelastic end constraint ...