Lateral-Torsional Buckling Resistance of Castellated Beams

Abstract

The existing design expressions for the lateral-torsional buckling behavior of castellated beams conflict. Furthermore, they do not take into account the detrimental effect of the residual stress modification attributable to the fabrication process, which was only recently demonstrated by the authors. This makes these design rules possibly unsafe. In this paper, the lateral-torsional buckling behavior of doubly symmetric castellated beams loaded by a constant bending moment is investigated numerically. The numerical model, including the modified residual stresses, was validated by comparing its results with experimental results. A preliminary design approach is proposed based on the current European guidelines for the calculation of the lateral-torsional buckling resistance of I-section beams. According to the proposed approach, the lateral-torsional buckling resistance of castellated beams can be determined using the cross-sectional properties calculated at the center of the web opening. The modification of the residual stresses during the fabrication process results in resistances that lie approximately one buckling curve lower.