To　investigate　the　influence　of　using　high-strength　steel　bars　in　columns　on　the　seismic　resistance　capacity　and　seismic　resilience　of　frame　structures,　seismic　fragility　evaluation　of　three　8-story　reinforced　concrete　(RC)　frame　structures　was　conducted　based　on　the　incremental　dynamic　analysis　(IDA)　using　11　ground　motion　records.　The　main　parameter　is　the　longitudinal　reinforcement　configuration　in　the　frame　columns,　where　the　first　structure　is　reinforced　with　HRB　600　grade　steel　bars　in　the　columns,　the　second　structure　is　replaced　with　equal　area　ultra-high-strength　(UHS)　steel　bars　(i.e.,　with　a　yield　strength　of　approximately　1425　MPa),　and　the　third　structure　is　replaced　with　equal　strength　UHS　steel　bars.　A　numerical　model　of　the　RC　frame　structure　was　developed　and　then　validated　using　previous　experimental　results.　The　exceeding　probabilities　at　various　performance　limit　states　were　calculated　based　on　two　typical　engineering　demand　parameters　(EDPs)　of　maximum　interstory　drift　and　residual　interstory　drift.　The　results　showed　that　using　UHS　longitudinal　steel　bars　instead　of　HRB　600　grade　steel　bars　in　frame　columns　could　reduce　the　energy　dissipation　capacity　of　the　structure,　inevitably　leading　to　an　increase　in　the　maximum　interstory　response　of　the　frame.　However,　much　lower　exceedance　probability　was　observed　in　the　UHS-enhanced　frame　under　the　repair　available　limit　state　based　on　the　residual　interstory　drift,　indicating　that　the　UHS-enhanced　RC　frame　had　higher　seismic　resilience.　In　addition,　compared　to　equal　area　substitution,　equal　strength　substitution　is　a　more　ideal　design　method　that　can　use　fewer　UHS　steel　bars　to　achieve　comparable　reparability　and　a　smaller　increase　in　maximum　interstory　drift.　©　2024　John　Wiley　&　Sons　Ltd.