Concrete-filled　double-tube　(CFDT)　columns,　which　are　a　new　type　of　composite　columns,　have　high　fire　resistance　and　the　potential　to　be　widely　used　in　high-rise　buildings.　It　is　expected　that　the　amount　of　steel　used　in　a　regular　CFDT　column　will　be　relatively　high　due　to　the　use　of　double　tubes.　To　reduce　the　steel　consumption,　a　thin-walled　steel　tube　with　longitudinal　stiffeners　may　be　adopted　for　the　outer　tube　in　a　CFDT　column.　This　paper　studies　the　behaviour　of　concrete-filled　stiffened　double-tube　(CFSDT)　stub　columns　under　axial　compression.　Tests　on　12　CFSDT　stub　columns　and　two　reference　columns　were　carried　out　accordingly,　and　the　test　results　confirm　that　the　stiffened　columns　have　high　strength　and　good　deformation　capacity.　A　finite　element　model　was　developed　to　analyse　the　interaction　between　the　steel　tubes　and　concrete.　Based　on　further　parametric　studies,　a　superposition　model　was　proposed　to　predict　the　axial　compressive　strength　of　CFSDT　stub　columns.　©　2017　Elsevier　Ltd