Generalized formula of moment gradient lateral torsional buckling factor for monosymmetric steel beams

• Published in: Port-Said Engineering Research Journal (Online) 2023-03, Vol.27 (1), p.35-53
• Main Authors: Sharaf, Tarek, Sayed, AMR, Elghandour, Mohamed, Elsabbagh, Ashraf
• Format: Article
• Language: English
• Subjects: finite element; lateral torsional buckling; moment gradient factor; monosymmetric sections; steel beams
• ISSN: 2536-9377; 1110-6603; 2536-9377
• DOI: 10.21608/pserj.2023.181357.1210

The lateral-torsional buckling (LTB) behavior of steel beams has been extensively reported. Most reports have been limited to study the doubly-symmetric beams besides a few other standard geometries. On the other hand, not so much research exists for monosymmetric steel beams, and LTB is one of the most critical design aspects for this type of beams. Codes allow the researchers to relate the critical moment to any in-plane loading to the standard uniform moment and members using the moment gradient factor. The moment gradient factor is an essential parameter in the design of steel cross-sections. Yet, it needs more to be applicable for cross-section shapes and boundary conditions. In this paper, a numerical model based on finite element analysis is presented, which is adopted to investigate the values of the moment gradient factor for different loading configurations. The model is developed to investigate the influence of load location with respect to the shear center of the beam section as well as the flange width ratio on the critical moment causing LTB. The numerical analysis results were validated, and new general equations for the moment gradient factor were developed to consider the effect of the different parameters.