Lateral torsional buckling of an I‐shaped hoisting spreader beam

Abstract

AbstractI‐shaped hoisting spreader beams are widely used in practice when lifting heavy objects by crane. In general, I‐shaped beams that are subjected to a bending moment may be sensitive to lateral torsional buckling. Eurocode 3 (1993‐1‐1 [1]) provides a calculation method to determine the lateral torsional buckling resistance using buckling curves. The method requires the elastic critical moment to calculate the relative slenderness. Different solutions for elastic critical moments are available which usually require fork end conditions. However, hoisting spreader beams do not have fork end conditions nor do they have lateral supports. Thus, the available calculation methods cannot be used and a new method is developed. A numerical model is validated against an experiment and subsequently used to investigate different types of spreader beam configurations. First a method to determine the elastic critical moment of a hoisting spreader beam is developed. Then the lateral torsional buckling resistance is evaluated using the buckling curves. The applicable buckling curve is determined by choosing the least conservative curve that can be used with a partial factor of 1.0. This results in buckling curve d to evaluate the lateral torsional buckling resistance of hoisting spreader beams.