Studies　have　consistently　identified　a　recurring　issue　of　debonding　at　the　interface　between　the　steel　tube　and　the　concrete　core　in　CFST　truss　arch　bridges.　To　address　this　challenge,　the　authors　propose　the　incorporation　of　inner　studs　along　the　inner　surface　of　the　steel　tube　at　the　joint　of　the　truss　arch　ribs.　Five　innovative　CFST　joint　specimens　were　fabricated　and　tested,　incorporating　key　variables　such　as　steel-concrete　interface　debonding,　the　presence　of　inner　studs　welded　to　the　internal　surface　of　the　steel　tube,　and　variations　in　web　member　diameter.　The　results　revealed　that　the　predominant　failure　mode　was　weld　tearing.　Furthermore,　the　initial　stiffness　of　the　CFST　joints　improved　with　the　introduction　of　inner　studs　and　an　increase　in　web　member　diameter.　The　presence　of　inner　studs　resulted　in　an　enhancement　of　shear　force　transmission　by　more　than　30　%.　To　further　explore　this　phenomenon,　detailed　finite　element　(FE)　model　were　developed　to　examine　the　underlying　force　transmission　mechanism.　The　length　and　angle　of　force　transmission　within　the　CFST　joint　were　quantitatively　characterized,　providing　insights　into　the　optimal　positioning　of　inner　studs　in　the　region　where　shear　forces　are　transferred.　©　2025　Elsevier　Ltd