EXPERIMENTAL INVESTIGATION ON THE BEHAVIOUR OF CONCRETE-FILLED STEEL COLUMNS

Steel sections with concrete infill are being increasingly used as structural members, since filling the steel section with concrete increases both its strength and ductility without increasing the section size. However, the limitations imposed by certain drawbacks of cement concrete are not alleviated or moderated by the encasing steel tube, like its high shrinkage, creep, brittleness, reactivity and low tensile strength, may be a hindrance to the rapid and diversified application of concrete filled steel tubes 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. In the present paper, experimental results of concrete–filled steel columns and polymer modified concrete filled steel columns under axial load combined with lateral cyclic loading are reported. Findings of these studies relating to the hysteresis response of filled steel composite columns subjected to axial compression combined with lateral cyclic load highlight the significant increase in ductility and energy absorption capacity of polymer modified concrete-filled steel columns.