Article: Strength and stability requirements of lateral bracing for compression flange in I-shaped beams Journal: International Journal of Structural Engineering (IJSTRUCTE) 2011 Vol.2 No.3 pp.273 - 302 Abstract: Lateral-torsional buckling is a limit state that can reduce the full benefit of beam capacity, especially for long elastic beams according to the big lateral deflection and cross-section twist of un-braced compression flange. Lateral-torsional buckling can be avoided by proper designed braces. These braces require not only adequate stiffness but sufficient strength as well. In this paper three dimensional, 3-D, finite element models, for I-shaped girders, are developed using a finite element programme and utilising it to investigate braces requirements and the geometrical parameters that may affect these requirements. These parameters are outstanding flange width-to-thickness ratio |cfl/tfl|, web height-to-thickness ratio |hw/tw|, flange width-to-web height ratio |bfl/hw|, multiple braces |n| and un-supported length-to-beam span |Lu/Lt|. Using the available finite element analysis results of the studied parameters, some design equations are proposed for the design of lateral braces of simply supported I-shaped beams subjected to any type of loading and restrained laterally by any number of braces. Inderscience Publishers - linking academia, business and industry through research

Title: Strength and stability requirements of lateral bracing for compression flange in I-shaped beams

Authors: Hany Esam Shabana, Sherif Abdel-Basset Ibrahim, Abdelrahim Khalil Dessouki

Addresses: Faculty of Engineering, Ain Shams University, 17 Tal El-hesn Street, Mataria, Cairo 11321, Egypt. ' Department of Civil Engineering, Faculty of Engineering, Ain Shams University, 1 El-sarayat Street, Abasis, Cairo 11517, Egypt. ' Steel Structures Division, Department of Civil Engineering, Faculty of Engineering, Ain Shams University, 1 El-sarayat Street, Abasis, Cairo, 11517, Egypt

Abstract: Lateral-torsional buckling is a limit state that can reduce the full benefit of beam capacity, especially for long elastic beams according to the big lateral deflection and cross-section twist of un-braced compression flange. Lateral-torsional buckling can be avoided by proper designed braces. These braces require not only adequate stiffness but sufficient strength as well. In this paper three dimensional, 3-D, finite element models, for I-shaped girders, are developed using a finite element programme and utilising it to investigate braces requirements and the geometrical parameters that may affect these requirements. These parameters are outstanding flange width-to-thickness ratio |c_fl/t_fl|, web height-to-thickness ratio |h_w/t_w|, flange width-to-web height ratio |b_fl/h_w|, multiple braces |n| and un-supported length-to-beam span |L_u/L_t|. Using the available finite element analysis results of the studied parameters, some design equations are proposed for the design of lateral braces of simply supported I-shaped beams subjected to any type of loading and restrained laterally by any number of braces.

Keywords: beam bracing; lateral bracing; stability requirements; compression flange; lateral-torsional buckling; finite element method; FEM; I-shaped beams; lateral deflection; cross-section twist; I-shaped girders; lateral braces; brace design.

DOI: 10.1504/IJSTRUCTE.2011.040784

International Journal of Structural Engineering, 2011 Vol.2 No.3, pp.273 - 302

Published online: 30 Sep 2014 *

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Title: Strength and stability requirements of lateral bracing for compression flange in I-shaped beams

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