Buckling Behaviors of Cold-Formed Steel Built-Up Columns under Axial Compression Tests: Review Paper

Cold-formed steel (CFS) sections constructed with high-strength steel have gained prominence in construction owing to their advantages, including a high strength-to-weight ratio, shape flexibility, availability in long spans, portability, cost-effectiveness, and design versatility. However, the thin thickness of CFS members makes them susceptible to various forms of buckling. This study focuses on addressing and mitigating different types of buckling in columns and beams by manipulating the lip length (d) and the ratio of inside radius to thickness (Ri/t) in CFS C-sections. To achieve this objective, a comprehensive analysis involving 176 models was conducted through the Finite Element Method (FEM). The findings reveal that an increase in lip length leads to a corresponding increase in critical elastic buckling load and moment (Pcrl, Pcrd, Pcre, Mcrl, Mcrd, and Mcre). It is recommended to utilize a lip length greater than or equal to 15 mm for both columns and beams to mitigate various buckling types effectively. Conversely, an increase in the ratio of inside radius to thickness (Ri/t) results in an increase in critical elastic local buckling load (Pcrl) and moment (Mcrl). Thus, lip length (d) significantly influences column and beam buckling, whereas Ri/t exhibits a relatively impactful effect. Subsequently, the experimental test results were used to verify finite element models. These insights contribute significant knowledge for optimizing the design and performance of CFS C-sections in structural applications.

Section: Impacts Of End Fastener Groups (Efgs) and End Conditions On ...mentioning

confidence: 99%

Effects of Lip Length and Inside Radius-to-Thickness Ratio on Buckling Behavior of Cold-Formed Steel C-Sections

Hussein,

Hussein

2024

“…However, "MPC constraints" are not suitable for simpler FE models [23]. According to one study [24], face-to-face built-up box sections with end plates are more effective than those without end plates. Additionally, the influence of the boundary condition on the members is negligible.…”

Section: The Influence Of Boundary Conditions On the Behavior Of Cfsmentioning

confidence: 99%

Investigating the Factors Influencing the Strength of Cold-Formed Steel (CFS) Sections

Hussein,

Hussein

2024

The utilization of cold-formed steel (CFS) sections in construction has become widespread due to their favorable attributes, including their lightweight properties, high strength, recyclability, and ease of assembly. To ensure their continued safe and efficient utilization, this review provides a comprehensive investigation into the factors influencing the strength of CFS members. This analysis encompasses design codes, prediction methodologies, material properties, and various structural configurations. This review uncovers discrepancies among existing design codes, particularly noting conservative predictions in AISI and AS/NZS standards for composite and built-up sections. Additionally, the effectiveness of prediction methods such as the direct strength method and effective width method varies based on specific structural configurations and loading conditions. Furthermore, this review delves into recent advancements aimed at enhancing fire resistance, connection design, and the composite behavior of CFS structures. The influence of factors such as eccentricity, sheathing materials, and bolt spacing on structural performance is also examined. This study underscores the crucial role of accurate prediction methods and robust design standards in ensuring the structural integrity and safety of CFS constructions. Through a comparative analysis, it is revealed that AISI and AS/NZS standards exhibit conservatism in predicting nominal buckling loads compared to experimental data. Conversely, a non-linear finite element analysis demonstrates a strong correlation with laboratory tests, offering a more accurate prediction of nominal buckling capacity. Overall, this review offers comprehensive insights aimed at optimizing CFS structural design practices. By identifying key areas for future research and development, this work contributes to the ongoing advancement of safe and efficient CFS construction applications.

“…In the case of applying EFGs on CFS columns, it is ineffective for local buckling and only works for flexural buckling mode, especially for built-up back-to-back steel columns [46]. Furthermore, when fastener groups are inserted in flexure elements at the sites of the highest shear slip, the slide between the webs is significantly decreased [39].…”

Section: Influence Of End Conditions and End Fastener Groups (Efgs)mentioning

confidence: 99%

“…Insufficient and accurate design standards, guidelines, and specifications are available for built-up CFS members, particularly when utilizing screws, bolts, and blind bolts [46]. Previous research has demonstrated that for members with a predominance of distortional and/or local buckling modes, the DSM design principles given by certain research are inappropriate, while the design standards currently in place exhibit a conservative approach [66].…”

Section: Challenges Of Inadequate Guidelines For Cfs Composite Elementsmentioning

confidence: 99%

See 1 more Smart Citation

State-of-the-Art: Integrating Fastener Technology and Design Guidelines for Enhanced Performance of Cold-Formed Steel Sections

Hussein,

Papp

2023

Cold-formed steel (CFS) elements have gained significant attention in the field of structural engineering due to their numerous advantages, including high strength-to-weight ratio, cost-effectiveness, and ease of assembly and prefabrication. This review paper presents a comprehensive state-of-the-art analysis of the design and analysis of CFS structures, with a specific focus on columns and beams. The primary objectives and aims of this review paper are to provide a detailed assessment of the factors influencing the behavior and performance of CFS elements, including partial composite action, fastener spacing, bolt arrangement, web aperture, stiffeners, and connection spacing, to propose and present various formulas and methodologies that accurately estimate critical buckling loads, strength, and moment resistance for CFS members, and to emphasize the significance of proper screw and bolt placement in preventing premature failure and enhancing the overall load-carrying capacity of CFS structures. Additionally, the impact of temperature on the mechanical properties and performance of CFS members is discussed. The review paper proposes different formulas and methodologies to accurately estimate critical buckling loads, strength, and moment resistance for CFS members. Moreover, the paper highlights the importance of proper screw and bolt placement to prevent early failure and improve the overall load-carrying capacity of CFS structures. The discussion also emphasizes the need for revisions in existing standards and codes to provide more practical guidelines for designers and engineers. Overall, this state-of-the-art review paper provides valuable insights and recommendations for researchers and practitioners involved in the design and analysis of CFS elements.