Experimental research on the bearing capacity of axially loaded composite columns with concrete core encased by steel tube

Abstract

The chapter explores fundamental characteristics of concrete columns reinforced with concrete-filled steel tube subjected to axial compressive loading. The use of composite steel-concrete columns has become widespread in recent decades. A composite column is a concrete column reinforced with a structural steel shape or tubing, in addition to reinforcing bars. Composite columns combine beneficial qualities of both steel and concrete, namely, high strength, excellent ductility, large energy absorption capacity, and convenience of erection. Consequently, a composite section is generally smaller than alternative designs to sustain the same load, thus resulting in the saving of material, weight, and headroom or construction depth. A steel-concrete composite column may be a concrete-encased column or a concrete-filled steel tubular column. The chapter studies effects of parameters, such as steel ratio of concrete-filled steel tube and volumetric ratio of transverse ties on the strength and deformation characteristics of composite columns, and proposes formulas to predict the ultimate strength of a composite section.