ABSTRACT
Concrete-filled tubes (CFT) are widely used in civil engineering and building construction and consist of a steel tube with a concrete core casted inside. The behavior of CFT has been widely studied and hundreds of tests on CFT subjected to axial and flexural loads are nowadays available in the literature (Goode 2008).Most of the studies have pointed out the beneficial effects of CFTwhen subjected to different types of loading by comparing their cross-sectional resistance and ductility to pure steel or pure concrete elements. Consensus concerning this matter has been achieved among researchers: due to an enhancement of the confined concrete strength, the resistance of CFT is quite higher than the addition of the resistances of each material when considered separately.The compressive strength is increased due to tri-axial confinement of the concrete core. The susceptibility to local buckling of the steel tube is decreased since the concrete core provides to the steel plate an additional constraint. This constraint prevents the plate to undergo inwards buckling and thus, the critical buckling load of the plate is increased.
