Experimental Investigation on Large-scale Slender FRP-Concrete-Steel Double-Skin Tubular Columns Subjected to Eccentric Compression

FRP-Concrete-Steel Double-Skin Tubular Columns (DSTCs) are a new form of hybrid columns which effectively combines the advantages of the constituent materials. A DSTC consists of an outer fibre-reinforced polymer (FRP) tube and an inner steel tube with the gap between filled with concrete. This paper presents the first-ever large-scale tests on slender DSTCs subjected to eccentric compression. The major parameters examined include the load eccentricity and the confinement stiffness of the FRP tube. Test results show that slender DSTCs possess good ductility under eccentric compression. Larger load eccentricity results in lower axial load capacity and higher deformability; larger confinement stiffness of the FRP tube results in larger axial load capacity and deformability. The axial strain distribution of a DSTC section subjected to eccentric compression generally conforms to the plane section assumption, but the ultimate axial strain of concrete is increased as a result of eccentric compression.