Behaviour of rectangular concrete-filled steel tubular slender column with unequal wall thickness

Abstract

Concrete-filled steel tubular (CFST) components have been widely adopted in engineering applications. Recently, an optimised configuration of rectangular CFST column, e.g., unequal-walled cross-section, has been proposed to replace the traditional section with an equal wall thickness under eccentrically compression. Application advantages of CFST column with unequal wall thickness in terms of load-bearing behaviour have been revealed by experimental and numerical studies. A series of compressive tests were carried out on rectangular CFST columns with varying slenderness, eccentricities and wall thicknesses. Test results show that the rectangular CFST column with unequal wall thickness possesses higher post-peak load ductility than the column with an equal wall thickness under the same configuration. Numerical simulations were proposed to predict the performance of the test specimens and a good agreement can be obtained between numerical and experimental results. Based on the validated numerical model, parametric studies were conducted to investigate the effect of the wall thickness, slenderness and eccentricity on the load-bearing capacity of the CFST column. It suggests that the ultimate load-bearing capacity of the unequal-walled columns can be optimised with proper flange thickness ratio and slenderness.