APPROXIMATE INELASTIC BUCKLING MOMENTS FOR DETERMINATE I-BEAMS

A method for estimating the inelastic buckling moment of a simply supported I-Beam under a moment gradient is proposed. The concept of the stiffness modification factor j, is introduced. The moment capacity is obtained from the elastic buckling moment and from the stiffness modification factor, the latter being related to the reduced lateral bending stiffness at the maximum moment or critical end of the partially yielded beam. Comparison of results with accurate computer curves shows that the proposed method gives good estimates of inelastic buckling moments. /Author/TRRL/