Experimental investigation on axial compressive behavior of novel FRP-ECC-HSC composite short column

Abstract

A novel composite column, consisting of an outer fiber reinforced polymer (FRP) tube, an engineered cementitious composite (ECC) ring and an inner high strength concrete (HSC) core, has been proposed and experimentally investigated in this study. Due to the high brittleness of HSC, localized cracks may occur and lead to premature failure for conventional FRP-confined HSC columns. With the excellent tensile and cracking behavior, ECC ring is used to redistribute the hoop stress and strain from HSC core to FRP tube in the proposed novel FRP-ECC-HSC composite column. A total of 12 stub columns with different HSC core strengths and ECC ring thicknesses were tested under axial compression. It is found that FRP-ECC-HSC composite columns can develop larger FRP confining efficiency with more uniform hoop strain distribution in comparison to the corresponding normal FRP-confined HSC columns. The ultimate axial strain is obviously enhanced as well for this composite column, leading to an improved ductile compressive behavior. Based on the test results obtained from this study, design equations are proposed to predict the ultimate loading capacity and ultimate axial strain for the FRP-ECC-HSC composite column.