Concrete-filled　steel　tubular　(CFST)　structures　have　been　widely　used　in　high-rise　buildings　and　long-span　bridges　for　the　high　strength　and　ductility　due　to　the　confinement　effect　of　the　concrete　core　provided　by　the　steel　tube.　This　beneficial　composite　action　could　be　damaged　by　circumferential　debonding　gap　(CDG),　which　is　nearly　unavoidable　in　real　CFST　structures.　Reliable　formulations　to　predict　the　influence　of　CDG　on　the　mechanical　performance　of　compressed　circular　CFST　columns　are　needed.　In　this　paper,　the　experimental　parameters　and　results　of　compressed　circular　CFST　columns　with　CDG　are　summarized　to　discuss　the　deficiencies　of　the　parameters　chosen　in　the　tests.　Detailed　finite　element　simulation　procedures　for　compressed　circular　CFST　columns　with　CDG,　based　on　ABAQUS,　are　then　introduced,　verifying　their　accuracy　by　test　results.　Based　on　the　validated　finite　element　models,　a　database　of　compressed　circular　CFST　columns　with　and　without　CDG,　including　strength,　ductility　and　stiffness　of　specimens　is　established;　it　is　obtained　by　covering　suitable　parameter　ranges　for　CDG　and　CFST　structures,　in　accordance　with　real　applications.　Successively,　new　formulations　able　to　predict　the　ultimate　load　capacity,　the　reduction　factor,　the　ductility　and　the　stiffness　of　specimens　are　derived　by　the　Evolutionary　Polynomial　Regression　(EPR)　methodology,　demonstrating　good　accuracy　and　low　complexity.