The collapse of steel model columns

Abstract An analytical study is made of the complete collapse behaviour of axially loaded Shanley model columns with steel flanges. The steel is assumed to be elastic-perfectly-plastic. The analysis includes the effect of one type of imperfection, namely an initial out-of-straightness of the column. Results are presented which illustrate the imperfection-sensitivity both of column strength and of pre-ultimate stiffness. The violence of collapse (post-ultimate stiffness) is also examined. Columns of intermediate slenderness and small imperfection, even if loaded in a stiff testing machine, exhibit a particularly dramatic, snap-through type of collapse behaviour.