Experimental investigation of concrete-filled and bare 6082-T6 aluminium alloy tubes under in-plane bending

The application of aluminium alloys in construction sector is increasing owing to their excellent corrosion resistance, light weight and attractive appearance. However, one of the main disadvantages of aluminium alloys is the low elastic modulus, which may cause a stability issue in aluminium structural members. The performance of aluminium tubes can be improved by filling concrete within them. Research on the flexural behaviour of concrete-filled aluminium alloy tubes is limited. This paper presents an experimental study on the behaviour of square and rectangular concrete-filled and bare aluminium tubular sections subjected to in-plane bending. Total 20 beams were tested, including 10 concrete-filled aluminium tubes (CFAT) and 10 bare aluminium tubes (BAT). The hollow aluminium tubes were fabricated using 6082-T6 alloy and filled with 25 MPa cylinder compressive strength concrete. The material properties of aluminium were measured by tensile test of coupons. It is shown that the flexural strength, stiffness and ductility of square and rectangular BAT flexural members was remarkably improved by the infilled concrete and the improvement is more pronounced for the thinner aluminium sections. Due to absence of design standards for CFAT beams, in this study the design rules available for concrete-filled steel tubular flexural members in the Eurocode 4 are considered by substituting the mechanical properties of steel with those of aluminium alloy. It is demonstrated that the proposed design rules provide good predictions of the flexural capacity of CFAT. KEYWORDS: 6082-T6 Aluminium alloy, Concrete-filled sections, Bare sections, Four-point bending, Flexural behaviour.