Numerical Investigation of Lateral–Torsional Buckling of T-shaped Steel Beams

• Author / Creator

  Manarin, Michael

• Lateral–torsional buckling (LTB) is a failure mode that is associated with simultaneous vertical displacement and twisting of a beam when subjected to flexural loading. LTB behaviour is generally well understood for I shaped steel beams; however, the LTB behaviour of T shaped steel beams is not as well understood. The aim of this study is to better understand the behaviour of T shaped steel beams in single curvature with the flange in compression through numerical finite element analysis, with a special focus on the moment gradient factor to consider the effect of varying moments along the beam axis. Eighteen T shaped beams were selected to represent the entire population cut from standard rolled wide-flange shapes in terms of various geometric properties (e.g., flange width and thickness, stem depth and thickness, second moment of area about the major and minor axes, and minimum slenderness ratio for elastic LTB to occur). Once validated, the finite element model was used to determine the elastic LTB behaviour, and consequently the moment gradient factor, for three loading scenarios with simply-supported end conditions: constant moment, point load, and uniformly distributed load. It was proposed that the CSA S16 14 moment gradient factor for doubly- and singly-symmetric I-shaped beams in single-curvature be utilized also for T shaped beams when in single-curvature with the flange in compression for the aforementioned loading cases.The finite element model was also used to investigate inelastic LTB behaviour. It was determined that class 1 and class 2 T shaped beams were able to achieve the plastic moment when they reached the cross-sectional capacity. The class 3 T-shaped beam also reached the plastic moment capacity when they reached the cross-sectional capacity; however, it may not be the case for all class 3 sections as they are susceptible to local buckling. Finally, the results were compared to CSA Standard S16 and changes were proposed to improve the estimation of the inelastic LTB critical moment.

• Subjects / Keywords

  • Lateral–Torsional Buckling
  • LTB
  • WT-sections

• Graduation date

  Fall 2019

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-abdf-5a50

• License

  Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.