Moment Gradient Factor for Lateral--Torsional Buckling of T-Shaped Beams
Lateral--torsional buckling (LTB) is a potential limit state for steel beams. Particularly, T-shaped beams (referred to as beams with WT-sections) can be sensitive to this failure mode due to the presence of only a single flange. Current LTB capacity equations in both CSA Standard S16 and AISC 360 neglect the moment gradient effect by prescribing a moment gradient factor of 1.0 when determining the critical moment for T-shaped beams. This study aims to assess the adequacy of the current moment gradient factor (1.0) for LTB capacity of simply supported T-shaped beams through numerical studies. The elastic critical moments of thirteen representative T-shaped beams subjected to a constant moment, a point load, or a uniformly distributed load are determined numerically using LTBeam and ABAQUS, a free and commercial software, respectively. Numerical analyses using both tools led to the finding that the elastic critical moments of T-shaped beams are affected by moment distributions. This study implies that T-shaped beams should have approximately the same moment gradient factor as I-shaped beams when subjected to single-curvature loading. Further work is required to assess the adequacy of the current moment gradient factor (1.0) in predicting the inelastic critical moments for LTB of simply supported T-shaped beams.
This SSRC paper, available via the link below, is restricted to members only.
If you haven't already done so, please log in to your AISC member profile or review membership options at aisc.org/join.
- Date: 4/2/2019 - 4/5/2019
- PDH Credits: 0
Michael Manarin, Robert G. Driver amd Yong Li; University of Alberta; Edmonton, Canada