The Lateral Instability of Unsymmetrical I Beams

Abstract

An expression is derived for calculating the critical bending moment at which lateral buckling will occur in an I beam which is unsymmetrical about the principal axis normal to the web. The expression is derived for the case in which the beam is subjected to pure bending. This problem differs from the similar problem involving the buckling of beams of symmetrical I crosssection in that the shear center of the section does not. coincide with the center of gravity. Experimental verification of the expression is obtained from the results of tests made to study the lateral buckling of unsymmetrical aluminum alloy I beams under pure bending.