Flexural buckling behaviour of concrete-filled double skin aluminium alloy columns: Fid-Bau Portal

Flexural buckling behaviour of concrete-filled double skin aluminium alloy columns

Bin Ali, Shafayat / Kamaris, George S. / Gkantou, Michaela

Highlights • The flexural buckling behaviour of concrete-filled double skin aluminium alloy columns is studied. • 8 columns are tested under axial compressive load. • A numerical parametric study including 81 columns is conducted. • A design methodology is proposed on the basis of Eurocode 4. • A design buckling curve is suggested.

Abstract Concrete-filled double skin steel tubular columns consisting of two hollow steel tubes and concrete infill between their interspace, have become popular in modern construction owing to their high ultimate load, less self-weight and good ductility. The weight of these columns can be reduced further by using lightweight aluminium alloy hollow tubes instead of steel ones. This paper experimentally and numerically studied the flexural buckling behaviour of the concrete-filled double skin aluminium tubular (CFDSAT) columns subjected to axial compression. A total of 8 CFDSAT columns were tested using a pin-ended set-up. The test results are presented in terms of failure modes, ultimate load and load versus mid-height lateral displacement curves. Non-linear finite element (FE) models of the specimens were developed and their accuracy was evaluated by comparing the FE and test results. A numerical parametric investigation was conducted to study the influence of the hollow ratio, the member slenderness, the cross-sectional slenderness of the hollow tubes and the concrete strength on the structural behaviour of CFDSAT columns. The parametric study results revealed that the cross-sectional dimensions of outer section, the member slenderness and the concrete compressive strength have a significant effect on the flexural buckling response of the columns, while the influence of the cross-sectional dimensions of inner section is less prominent. In the absence of design standards for CFDSAT members, a design methodology is proposed with a design buckling curve to predict the ultimate load of CFDSAT columns based on the Eurocode 4 framework. Moreover, a revised concrete correction factor is suggested to determine the effective flexural rigidity of CFDSAT columns according to Eurocode 4.