NUMERICAL INVESTIGATION AND PARAMETRIC STUDY ON THE BEHAVIOUR OF
AXIALLY LOADED BACK-TO-BACK GAPPED BUILT-UP COLD-FORMED STEEL CHANNELS
Krishanu Roy 1*, Tina Chui Huon Ting 2, Hieng Ho Lau3 and James B.P. Lim 1
1 Department of Civil and Environmental Engineering, The University of Auckland, New Zealand
2 Faculty of Engineering and Science, Curtin University Malaysia, Miri, Sarawak, Malaysia
3 Faculty of Engineering, Computing and Science, Swinburne University of Technology, Sarawak Campus, Kuching, Sarawak, Malaysia
This paper presents a ﬁnite element investigation to investigate the axial capacity of CFS channels, connected back-to-back with a gap. A ﬁnite element model was ﬁrstly developed and veriﬁed against test results, currently conducted on CFS built-up gapped columns by the authors. Initial imperfections and material properties of the test specimens were included in the FE model. The column strengths, buckling modes, load verses displacement and load verses strain relationships were predicted from the FEA and compared against the test results. The veriﬁed FE was used for an extensive parametric study, comprising 84 models to investigate the effect of the gap between the back-to-back channels, link channel spacing, different column lengths and cross-sectional geometries. The FE results together with the test results were compared against the design strength, calculated in accordance with the AISI and AS/NZ Standard, which showed that the design standards can be conservative by only 5% when non-dimensional slenderness that considers the gap, is used to calculate the design strength of such columns.
Gap, Cold-formed steel, Back-to-back gapped sections, Buckling, Finite element analysis, Axial capacity.