To　advance　the　application　of　sustainable　recycled　aggregate　concrete　(RAC)　in　bridge　engineering,　this　study　introduces　a　novel　reinforced　RAC-filled　circular　steel　tubular　(RRACFCST)　column,　leveraging　the　dual　confinement　of　an　external　steel　tube　and　an　internal　reinforcement　cage.　Its　primary　novelty　is　a　comprehensive　analytical　framework　integrating　a　new　theoretical　model　by　using　limit　analysis,　ferrule　theory,　and　the　twin　shear　unified　strength　theory.　Then,　a　rigorously　validated　nonlinear　finite　element　model　that　incorporated　material　nonlinearity　and　interface　effects　was　used　to　validate　the　proposed　theoretical　model.　The　results　demonstrate　the　significant　performance　of　the　steel　reinforcement　cage,　which　enhanced　the　axial　bearing　capacity　by　17.86%,　and　an　optimal　recycled　aggregate　replacement　rate　of　70%　yielded　the　bearing　capacity,　with　100%　replacement　still　achieving　a　13.3%　higher　capacity　than　unconfined　conventional　concrete,　demonstrating　how　effective　confinement　can　compensate　for　and　overcome　the　inherent　deficiencies　of　RCA.　Conversely,　larger　diameter–thickness　ratios　would　reduce　the　strength　by　33.7%.　These　quantifiable　findings　provide　critical　design　insights　and　a　validated　predictive　tool,　establishing　the　RRACFCST　column　as　a　promising　and　high-performance　sustainable　solution　for　bridge　structures.　©　2025　by　the　authors.