It　is　generally　expected　that　inner-welded　longitudinal　stiffeners　can　be　used　to　improve　the　structural　performance　of　thin-walled　hollow　steel　structural　stub　columns　filled　with　concrete.　Thirty-six　specimens,　including　30　stiffened　stub　columns　and　six　unstiffened　ones,　were　tested　to　investigate　the　improvement　of　ductile　behaviour　of　such　stiffened　composite　stub　columns　with　various　methods.　The　involved　methods　include　increasing　stiffener　height,　increasing　stiffener　number　on　each　tube　face,　using　saw-shaped　stiffeners,　welding　binding　or　anchor　bars　on　stiffeners,　and　adding　steel　fibres　to　concrete.　It　has　been　found　that　adding　steel　fibres　to　concrete　is　the　most　effective　method　in　enhancing　the　ductility　capacity,　while　the　construction　cost　and　difficulty　will　not　be　increased　significantly.　©　2008　Elsevier　Ltd.　All　rights　reserved.