On torsional stability of cruciform columns

Abstract

Elastic bifurcation load of torsional buckling of centrally loaded thin-walled columns with a (basic) cruciform cross-section and a built-up cross-section formed by four equal-leg angles is considered first. For the latter cross-section, diagrams of equivalent slenderness in torsional buckling as a function of span length are shown. In the second part an empirical formula for the ultimate load of basic cruciform columns is given—accounting for the beneficial effect of restraint at the loading platens at large rates of twist. The formula is compared with the test results of another author.