Applicable equivalent bow imperfections in GMNIA for Eurocode buckling curves – SHS, RHS and welded box sections. (May 2023)

• Record Type: Journal Article
• Authors: Somodi, B.; Bärnkopf, E.; Kövesdi, B.
• Is Part Of: Journal of constructional steel research. Volume 204(2023)
• Publication Date: 2023-05
• Subjects: Flexural buckling -- GMNIA -- Closed section -- Equivalent imperfection -- High strength steel; Steel, Structural -- Periodicals; Building, Iron and steel -- Periodicals; Acier de construction -- Périodiques; Construction métallique -- Périodiques; 624.1821
• DOI: 10.1016/j.jcsr.2023.107860
• Languages: English
• ISSNs: 0143-974X

Abstract

Abstract: The direct resistance check using advanced numerical models is spreading among designers nowadays. Therefore, the development of accurate and up-to-date design rules supporting the FEM-based design of slender steel structures is an important task and prospective research field. Using the direct resistance check, the load carrying capacity of the steel structure under investigation is obtained as a result of geometrical and material nonlinear analysis using imperfections (GMNIA). The present paper investigates the imperfection magnitudes of slender steel columns and specifies the accurate value of the equivalent geometric imperfection to be applied for welded square, cold-formed and hot-rolled square (with rounded corners), and rectangular sections. Using the proposed imperfection magnitude, the load carrying capacities can be determined by GMNI analysis and the obtained results will be identical or very close to the buckling resistances calculated by the buckling curves of the Eurocode. The developed imperfection magnitude is given in closed form as a function of relative slenderness, steel strength and buckling curve parameter (imperfection factor α). Details on the determination of the necessary equivalent geometric imperfection and the obtained trends on the flexural buckling resistance are presented in the current paper. Highlights: Flexural buckling of steel closed sections analysed using numerical GMNIA. Equivalent imperfection is calculated to reach load-capacity level of Eurocode. Square welded box sections and hollow sections are analysed from S235 up to S960. Rectangular welded box sections are analysed having S355 steel grade. Imperfection magnitude is developed in closed form for each analysed scenario.