Testing and FE simulation of lightweight CFS composite built-up columns: Axial strength and deformation behaviour.

The limited past research on light-weight cold-formed steel (CFS) composite sections have indicated their success in addressing the buckling instabilities, but have been confined to flexural members. Thus, there is a need to extend this research to columns as well. In the first part of this study, an experimental investigation was carried out on lightweight CFS composite built-up battened columns composed of channel sections, connected in the face-to-face configuration. Two series of tests were performed to evaluate the axial compression capacity and stability response of built-up sections formed using various light-weight materials like GFRP and timber, as composites with CFS channels. The structural performance of these composite built-up battened columns was assessed in terms of their peak loads resisted, load–displacement response, axial stiffness, failure modes and strength-to-weight comparison. The second part deals with the theoretical analysis of the lightweight CFS composite built-up sections using the current codes for checking their adequacy. The third part presents the finite element simulation of the lightweight CFS composite built-up sections for validating the test results. • Light-weight CFS composite built-up columns are developed using GFRP and timber. • Monotonic tests performed to explore the structural behaviour of composite columns. • FE simulation of the behaviour of such composite built-up columns is carried out. • Theoretical strengths were determined and compared with the test strengths. • Large improvement in the strength, stiffness & strength-to-weight ratio is achieved. [ABSTRACT FROM AUTHOR]