Experimental and numerical study on lateral-torsional buckling of singly symmetric Q460GJ steel I-shaped beams

Metallic thin-walled beams with continuously varying cross-sections loaded in compression are particularly sensitive to instability problems due to lateral-torsional buckling. Such a phenomenon depends on several parameters, including the cross-sectional properties along the entire length, material properties, load distribution, support, and restraint conditions. Due to the difficulty of obtaining analytic solutions for the problem under consideration, the present study takes a numerical approach based on a variational formulation of the lateral-torsional buckling problem of tapered C-beams. Numerical simulations are compared with experimental results on the buckling of a physical model of at thin-walled beam with uniformly varying cross-section, with the aim of assessing the accuracy of the proposed approach. The good agreement between numerical and experimental results and the reduced computational effort highlight that the proposed variational approach is a powerful tool, provided that the geometry of the structure and the boundary conditions are accurately modeled.

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Experimental and numerical study on the lateral torsional buckling of full-scale steel-timber composite beams

Advances in Structural Engineering ◽

10.1177/13694332211057263 ◽

2021 ◽

pp. 136943322110572

Author(s):

Ying Gao ◽

Feiyang Xu ◽

Xinmiao Meng ◽

Ye Zhang ◽

Hongda Yang

Keyword(s):

Composite Beam ◽

Numerical Study ◽

Shear Stiffness ◽

Composite Beams ◽

Full Scale ◽

Physical Parameters ◽

Lateral Torsional Buckling ◽

Torsional Buckling ◽

Interface Shear ◽

Composite Action

The lateral torsional buckling (LTB) of steel-timber composite (STC) beam with partial interaction was investigated in this paper. The composite beam is constructed by connecting the timber to both flanges of the H-shaped steel with bolts or screws. Twelve push-out specimens were designed to evaluate the shear performance of bolt or screw connectors. It was shown that the slip stiffness and the shear bearing capacity of the connectors increased with the thickness of timber increasing. Then, eight full-scale composite beams with lengths of 6000 mm were studied through bending tests and compared to a bare steel beam. The experimental behaviors of the specimens were identified, including the failure mode, load-deflection relationship and load-strain response. The LTB phenomenon and composite action were discussed by analyzing the strain distribution, stiffness and strength. The results demonstrated that the STC beams fastened with bolts or screws displayed partial composite action. Although the stiffness of the composite beam showed little augmentation, the maximum strength of the composite beam substantially increased by suppressing the LTB phenomenon. A finite element analysis was conducted to reveal the failure mechanism of the specimens with different geometric and physical parameters, including the number of timber layers, the interface shear stiffness and the initial imperfection. It was found that increasing the number of timber layers in the upper flange suppressed the lateral torsional buckling, and the interface shear stiffness was the key factor to control the stiffness and failure modes of STC beams.

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A Numerical Study on Inelastic lateral Torsional Buckling Strength of Doubly Stepped and Singly Symmetric I-Beam Subjected to Uniform Moment

Journal of the Korea Academia-Industrial cooperation Society ◽

10.5762/kais.2013.14.7.3495 ◽

2013 ◽

Vol 14 (7) ◽

pp. 3495-3501 ◽

Cited By ~ 1

Author(s):

Yi Seul Park ◽

Jong Sup Park

Keyword(s):

Numerical Study ◽

Lateral Torsional Buckling ◽

Torsional Buckling ◽

Buckling Strength

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PARAMETRIC STUDY ON THE LATERAL TORSIONAL BUCKLING OF STAINLESS STEEL I BEAMS WITH CLASS 4 CROSS-SECTIONS IN CASE OF FIRE

Applications of Structural Fire Engineering ◽

10.14311/asfe.2015.020 ◽

2016 ◽

Author(s):

Nuno Lopes ◽

Pedro Gamelas ◽

Paulo Vila Real

Keyword(s):

Stainless Steel ◽

Cross Sections ◽

Elevated Temperatures ◽

Numerical Study ◽

Design Guidelines ◽

Steel Grade ◽

Steel Beams ◽

Lateral Torsional Buckling ◽

Torsional Buckling ◽

Steel Members

For predicting the behaviour of beams with thin-walled I sections, named Class 4 in Eurocode 3 (EC3), it is necessary to account for the occurrence of both local and lateral torsional buckling (LTB). These instability phenomena, which are intensified at elevated temperatures, should be accurately considered in design rules. The fire design guidelines for stainless steel members, given in Part 1-2 of EC3, propose the use of the same formulae developed for carbon steel (CS) elements. However, these two materials have different constitutive laws, leading to believe that the use of those formulae should be validated. This work presents a parametric numerical study on the behaviour of stainless steel beams with Class 4 I sections at elevated temperatures. The influences of several parameters such as stainless steel grade, loading type and cross section slenderness are evaluated, and comparisons between the obtained numerical results and EC3 rules are presented.

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