Restrained Crooked Aluminum Columns

The strength of aluminum pinned crooked columns has been derived as the basis of a design column curve. The effective length factor concept has then been presented and a value for crooked columns introduced (K_crooked). This factor can only be numerically determined and has no direct theoretical relation with the classical effective length factor (K_el) derived from elastic buckling analyses. Many examples have, however, shown that K_crooked is less than K_el and that it is conservative to base a design on K_el and a column curve derived for pinned crooked columns. It has also been shown that the amount of restraint necessary to compensate the effect of initial imperfection is strongly dependent on the slenderness ratio of the member.