This　paper　investigates　the　axial　compressive　behavior　of　concrete-filled　steel　tube　(CFT)　columns　with　embedded　FRP　tubes　by　the　following　three　steps:　(i)　compiling　a　comprehensive　experimental　database　consisting　of　47　tests,　(ii)　conducting　294　parametric　analyses　using　benchmarked　FE　models　to　investigate　the　effect　of　relative　strength　factor　on　the　strength　enhancement　ratio,　and　(iii)　evaluating　current　design　equations　using　the　results　from　the　database　and　FE　parametric　analyses.　The　insufficiencies　of　current　equations　were　identified,　leading　to　the　development　of　a　new　unified　design　equation.　This　proposed　design　equation　explicitly　accounts　for　the　strength　enhancement　achieved　by　embedding　FRP　tubes　into　CFT　columns,　providing　improved　accuracy　in　estimating　the　axial　compressive　strength　of　SCFC　columns　over　a　wider　range　of　material　strength　and　geometric　parameters　(e.g.,　yield　strength　of　steel　and　compressive　strength　of　concrete　up　to　960　MPa　and　100　MPa,　respectively).　©　2024　Institution　of　Structural　Engineers