Equivalent sway imperfections for use in structural steel design by GNIA
Year: 2024
Type: article
Abstract: Typically, sway imperfections refer to the out-of-plumbness of structural frames and are a key modelling requirement in design by geometrically nonlinear analyses with imperfections (GNIA). Equivalent geometric imperfections, accounting for the combined influence of initial geometric imperfections , the spread of plasticity and residual stresses, are used for modelling convenience. In EN 1993-1-1, the equivalent member bow imperfection amplitudes for use in design by GNIA e 0 , GNIA are dependent on the imperfection factor α ( i.e. the assigned buckling curve), the material parameter ε , the axis of buckling and the type of cross-section resistance check to be performed. By contrast, for equivalent sway imperfections ϕ 0 , GNIA , two constant values – one for elastic and one for plastic cross-section checks – are provided. The dependency of e 0 , GNIA on the imperfection factor α and the material parameter ε rightly reflects the varying influence of residual stresses and material grade on member buckling. However, sway buckling is also influenced by residual stresses and material grade; the suitability of the current EN 1993-1-1 provisions for ϕ 0 , GNIA is therefore questioned. In the present paper, new equivalent sway imperfections suitable for use in the design of steel and stainless steel structures by GNIA ϕ 0 , GNIA are proposed. The new proposals are shown to be able to provide improved capacity predictions, particularly for stainless steel structures , and are recommended for inclusion into future revisions of Eurocode 3.
Authors: H.U. Chan, F. Walport, L. Gardner
Institutions: Imperial College London, University College London
Language: English
Subfield: Civil and Structural Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,180
OpenAlex ID: W4403462707