Distortional-Global Buckling Interaction Relevance in Cold-Formed Steel Lipped Channel Columns

Lazzari, João Alfredo de; Batista, Eduardo de Miranda

doi:10.1590/1679-78256264

Cited by 3 publications

(3 citation statements)

References 39 publications

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“…Figure 18 presents the results of the comparison between FEM and design proposal versus the global-local or distortional slenderness ratio, PFEM/PnLD vs. G/maxLD. The FEM results are related to CFS lipped channel columns [10,13,14,16,21,23,25,26], for which the previous restriction of λG/λmaxLD ≤ 0.40 was released. The effect of the global buckling is clear in this figure , showing the tendency of lower strength ratio for G/maxLD>0.40, because PnLD equations does not take into account neither flexural or flexural-torsional buckling modes.…”

Section: Assessment Of the Global Buckling Modementioning

confidence: 99%

“…Beyond the cited DSM rules for CFS columns, it could be argued if other than LG interaction modes should be considered: LD, DG and LDG. Actually, LD and DG interaction modes have been investigated, as reported by many authors [7][8][9][10][11][12][13][14][15][16][17][18][19] for the case of LD and [20,21] for DG. LDG triple buckling modes interaction have been also investigated [22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

“…Figure21 Result of the calibration of coefficients C, D, E and F, for RλDL = 0.90 and λG/λmaxLD equal to 0.80, 0,90 and 1,00, according with the FEM results submitted to the minimum square method.…”

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confidence: 99%

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CFS Columns Under Buckling Interaction: Direct Strength Method Generalised Approach

Masubara

Batista

2022

ce papers

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Cold‐Formed Steel (CFS) members are highly susceptible to several structural instability phenomena, involving either individual (Local – L, Distortional – D and Global – G) or interaction (LD, LG, DG, and LDG) buckling modes. The buckling mode interaction of CFS columns and beams may lead to strength erosion compared to isolated modes and must be considered in structural design. The North American, Australian/New Zealand and Brazilian standards incorporated the Direct Strength Method (DSM) that provides accurate design approach for columns and beams affected by L, D, G, and LG buckling modes. Moreover, the coupled LD, DG, and LDG buckling modes are not currently considered in the DSM and many research projects have been focused on these topics. The procedure adopted by DSM estimates the CFS member strength through experimentally calibrated design strength curves, considering the relationship between the member elastic stability and the steel yielding property. In this context, the present paper presents the main results of the investigation, based on both experimental and finite element method numerical results, that conducted to calibrated Winter‐type strength curves for CFS columns covering LD, DG, and LDG buckling modes. To take into account the effect of the buckling modes interaction, the proposed procedure for design purposes incorporates the slenderness factors ratio RλDL = λD/λL and λG/ λmaxLD, with λmaxLD = max {λL, λD} and λL, λD, λG as the local, distortional and global slenderness factors, respectively.

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Section: Assessment Of the Global Buckling Modementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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CFS Columns Under Buckling Interaction: Direct Strength Method Generalised Approach

Masubara

Batista

2022

ce papers

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Distortional–Global Interactive Buckling of Thin-Walled Columns with Complex Lips

2023

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Structural behaviour of built-up I-shaped CFS columns

Hussein

2024

Sci Rep

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The utilization of cold-formed thin-walled members as structural members has gained significant popularity due to their advantages in fabrication, cost-effectiveness, and transportation convenience. However, the reduced thickness of the used sections poses challenges such as global, local, and distortional member buckling, leading to a decrease in their axial strength. This study focuses on addressing these challenges by connecting the channels together using screws as an alternative to welding, considering the cost, time, and ease of implementation. Conducting finite element analysis on structural columns built-up from cold-formed double C steel channels and subjected to axial loads, this paper verifies the numerical models used against experimental tests known from the literature. A comparison of experimental results with nonlinear FEA and AISI & AS/NZ standards reveals commendable agreement, particularly in predicting the buckling behavior of the built-up I-shaped CFS columns. While the results of the finite element analysis show an overestimation of approximately 3.6% compared to the experimental tests, the AISI and AS/NZS standards demonstrate a conservatism of about 3.0%. Furthermore, the current study investigates the influence of screw spacing on axial strength of built-up cold-formed steel columns. The findings are derived from 175 finite element experiments, evaluating seven different cross-sectional profiles with twelve distinct screw spacings. These spacings correspond to the half-wavelength of local, distortional, and global buckling, divided by values ranging from one to four. The screw spacing determined by half the local buckling half-wavelength along the webs’ centerline resulted in enhancements of 22%, 7%, 13%, and 11% in the critical elastic local, distortional, and global column buckling loads, as well as the nominal axial strength, respectively. These increases were even more pronounced for double-lane fasteners with the same spacing, yielding improvements of 25%, 46%, 17%, and 12%, respectively. For economic considerations, it is advisable to utilize single-lane fasteners with a half-wavelength equal to half the local buckling half-wavelength.

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Distortional-Global Buckling Interaction Relevance in Cold-Formed Steel Lipped Channel Columns

Cited by 3 publications

References 39 publications

CFS Columns Under Buckling Interaction: Direct Strength Method Generalised Approach

CFS Columns Under Buckling Interaction: Direct Strength Method Generalised Approach

Distortional–Global Interactive Buckling of Thin-Walled Columns with Complex Lips

Structural behaviour of built-up I-shaped CFS columns

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