1. Department of Civil Engineering, Kobe City College of Technology, Gakuenhigashimachi 8-3, Nishi, Kobe 651-2194, Japan;2. Department of Urban Engineering, Osaka City University, Japan;3. Osaka City University, Japan
Abstract:
Concrete filled double skin tubular (CFDST in abbreviation) stub columns consist of double concentric thin steel tubes and filled concrete between them. Their mechanical behaviors under axial compression were investigated experimentally. Two testing parameters considered were inner-to-outer diameters ratio and diameter-to-thickness ratio. Observed failure modes were controlled by the local buckling of both the tubes associated with shearing failure of the filled concrete. Main discussion is given on confinement effect by the outer tube to the filled concrete strength. Equations to estimate their ultimate strengths under compression were proposed based upon the yielding strengths of the tubes and the filled concrete cylinder strength.