Polymer concrete-filled steel tubes under axial compression

Concrete-filled steel tubular (CFT) structures are rapidly emerging as one of the inevitable structural systems for earthquake resistance, as they have been known to exploit the best attributes of both steel and concrete, resulting in higher stiffness, strength and ductility. However, the limitations imposed by certain drawbacks of cement concrete and which are not alleviated or moderated by the encasing steel tube, e.g. its high shrinkage, creep, brittleness, reactivity and low tensile strength, may be a hindrance to the rapid and diversified application of CFTs, in line with current emphasis on ductility-based seismic design. In this context, studies are presently being conducted on filled steel composite members, employing lighter, more ductile, high tensile strength and inert polymer-based fill materials for the steel tube. Findings of these studies relating to the elasto-plastic response of filled steel composite stub columns subjected to axial compression highlight the significant increase in strength and/or ductility of epoxy polymer concrete-filled steel columns.