Details
| Original language | English |
|---|---|
| Pages (from-to) | 141-158 |
| Number of pages | 18 |
| Journal | Engineering journal |
| Volume | 61 |
| Issue number | 3 |
| Publication status | Published - 1 Jul 2024 |
Abstract
Lateral torsional buckling (LTB) is of concern in long-span flexural members, particularly in the negative flexure regions of continuous-span, steel I-shaped members and during construction. While the elastic critical LTB capacity of a simply supported I-shaped member subjected to uniform moment has a closed-form solution, most LTB modification factors for beams subjected to moment gradients in the literature are empirical and work well only for specific loading and boundary conditions. This paper investigates the suitability of the different LTB modification factors in literature and design specifications for various loading and boundary conditions, accomplished via comparisons with analytical solutions using the Rayleigh-Ritz method and numerical solutions from finite element analyses. The analytical LTB modification factors are derived for doubly symmetric I-shaped members with different combinations of ideal flexural and torsional boundary conditions (simply supported and fixed) and subjected to different loading scenarios. The validity of the LTB modification factors determined using the Rayleigh-Ritz method and other formulae in the literature are also assessed for realistic intermediate restraint conditions, which are neither fully pinned nor fixed, by examining laterally continuous beams. Demonstrating that current design specifications for elastic critical LTB modifications are overly conservative for beams with complete or partial warping fixity, the authors recommend practical and simple alternatives to design such beams.
Keywords
- continuous beams, lateral torsional buckling, LTB modification factor, Rayleigh-Ritz method, warping restraints
ASJC Scopus subject areas
- Engineering(all)
- Civil and Structural Engineering
- Engineering(all)
- Building and Construction
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In: Engineering journal, Vol. 61, No. 3, 01.07.2024, p. 141-158.
Research output: Contribution to journal › Article › Transfer › peer review
}
TY - JOUR
T1 - Lateral-Torsional Buckling Modification Factors in Steel I-Shaped Members
T2 - Recommendations Using Energy-Based Formulations
AU - Nayak, Namita
AU - Anilkumar, P. M.
AU - Subramanian, Lakshmi
N1 - Publisher Copyright: © 2024, American Institute of Steel Construction Inc.. All rights reserved.
PY - 2024/7/1
Y1 - 2024/7/1
N2 - Lateral torsional buckling (LTB) is of concern in long-span flexural members, particularly in the negative flexure regions of continuous-span, steel I-shaped members and during construction. While the elastic critical LTB capacity of a simply supported I-shaped member subjected to uniform moment has a closed-form solution, most LTB modification factors for beams subjected to moment gradients in the literature are empirical and work well only for specific loading and boundary conditions. This paper investigates the suitability of the different LTB modification factors in literature and design specifications for various loading and boundary conditions, accomplished via comparisons with analytical solutions using the Rayleigh-Ritz method and numerical solutions from finite element analyses. The analytical LTB modification factors are derived for doubly symmetric I-shaped members with different combinations of ideal flexural and torsional boundary conditions (simply supported and fixed) and subjected to different loading scenarios. The validity of the LTB modification factors determined using the Rayleigh-Ritz method and other formulae in the literature are also assessed for realistic intermediate restraint conditions, which are neither fully pinned nor fixed, by examining laterally continuous beams. Demonstrating that current design specifications for elastic critical LTB modifications are overly conservative for beams with complete or partial warping fixity, the authors recommend practical and simple alternatives to design such beams.
AB - Lateral torsional buckling (LTB) is of concern in long-span flexural members, particularly in the negative flexure regions of continuous-span, steel I-shaped members and during construction. While the elastic critical LTB capacity of a simply supported I-shaped member subjected to uniform moment has a closed-form solution, most LTB modification factors for beams subjected to moment gradients in the literature are empirical and work well only for specific loading and boundary conditions. This paper investigates the suitability of the different LTB modification factors in literature and design specifications for various loading and boundary conditions, accomplished via comparisons with analytical solutions using the Rayleigh-Ritz method and numerical solutions from finite element analyses. The analytical LTB modification factors are derived for doubly symmetric I-shaped members with different combinations of ideal flexural and torsional boundary conditions (simply supported and fixed) and subjected to different loading scenarios. The validity of the LTB modification factors determined using the Rayleigh-Ritz method and other formulae in the literature are also assessed for realistic intermediate restraint conditions, which are neither fully pinned nor fixed, by examining laterally continuous beams. Demonstrating that current design specifications for elastic critical LTB modifications are overly conservative for beams with complete or partial warping fixity, the authors recommend practical and simple alternatives to design such beams.
KW - continuous beams
KW - lateral torsional buckling
KW - LTB modification factor
KW - Rayleigh-Ritz method
KW - warping restraints
UR - http://www.scopus.com/inward/record.url?scp=85200248289&partnerID=8YFLogxK
U2 - 10.62913/engj.v61i3.1328
DO - 10.62913/engj.v61i3.1328
M3 - Article
AN - SCOPUS:85200248289
VL - 61
SP - 141
EP - 158
JO - Engineering journal
JF - Engineering journal
SN - 0013-8029
IS - 3
ER -