Lateral Buckling Approximations for Elastic Beams

A simple hand method of calculating very good estimates of the elastic lateral buckling loads of laterally continuous beams is developed in this paper. The method uses an equivalent uniform moment concept to allow for the type of loading on the beam, and an effective length concept to allow for the interactions at the brace points between adjacent segments. Few additionalcomputations are required over and above those necessary to determine the commonly calculated lower bound estimate of the buckling load, since the additional calculations of the new method are made only for the most critical segment. Comparisons of the predictions of the proposed method and of the lower bound method with the accurate finite element results show that the proposed method consistently leads to far more accurate predictions.

D.A. Nethercot and N.S. Trahair