Experimental modeling of stability of single bay single storey frames

Rigid frames subjected to critical loads are assumed to fail when the columns fail. The attached beams act as partial elastic restraints to the columns while the base supports are assumed to be pinned or fixed. This study presents the results of extensive laboratory investigation of the critical load of steel frames models of various stiffness values (K = 0.5, 0.75, 1.0, 1.25 and 1.5) with fixed and pinned supports respectively. The critical load values and lateral deflection obtained from experiments are plotted against the beam column stiffness ratios kb/kc. Based on the test results, a linear relationship between the critical load and the selected stiffness ratios of the frame models was established within the elastic range. The results were used to validate the works of some recently proposed approximate formulae and empirical model for stability of frame. These results deviate from the selected approximate method approach by approximately ± 10%.