This　paper　studies　the　behavior　of　concrete-encased　concrete-filled　steel　tube　(CFST)　members　under　axial　tension.　Experimental　results　of　thirteen　specimens　were　reported.　The　variables　in　the　test　were　the　diameter　of　the　steel　tube,　bond　condition　between　the　inner　CFST　and　outer　reinforced　concrete　(RC)　components.　Push-out　tests　were　conducted　to　investigate　the　bond　performance　between　the　inner　CFST　and　outer　RC　components.　A　finite　element　model　(FEM)　was　then　developed　to　perform　further　analysis　on　the　tensile　behavior　of　the　concrete-encased　CFST　member.　The　internal　load　distribution　between　the　inner　CFST　and　outer　RC　components,　the　interaction　between　the　core　concrete　and　steel　tube,　and　the　interaction　between　the　outer　concrete　and　steel　tube　were　investigated.　The　core　concrete　and　steel　tube　worked　together　well,　and　the　tensile　strength　of　the　steel　tube　was　enhanced　because　of　the　＂composite　effect,＂while　the　outer　RC　component　was　separated　from　the　inner　CFST　and　thus　worked　independently.　In　addition,　the　bond　strength　between　the　steel　tube　and　outer　concrete　is　larger　than　that　between　the　steel　tube　and　core　concrete.　Based　on　the　full　range　analysis　and　parametric　analysis,　a　simplified　model　was　proposed　to　predict　the　tensile　strength　of　concrete-encased　CFST　members,　and　generally　good　agreement　was　achieved　between　the　predictions　and　test　results.　(C)　2015　American　Society　of　Civil　Engineers.