Piers　are　key　components　in　a　lateral　force　resisting　system　of　bridge　structures.　To　implement　the　multiple　performance　objectives　of　probability-based　and　performance-based　seismic　design　for　bridge　structures,　the　probabilistic　capacity　of　piers　need　to　be　calculated　at　various　performance　limit　states.　Based　on　previous　research　works,　5　seismic　performance　levels　and　4　corresponding　performance　limit　states　are　defined　for　RC　bridge　columns.　The　deterministic　formula　for　deformation　capacities　of　RC　bridge　columns　at　each　performance　limit　state　is　derived　from　equivalent　plastic　hinge　theory.　On　the　basis　of　quasi-static　test　results　of　183　rectangular　flexure　dominant　RC　bridge　columns,　the　coefficients　associated　with　the　axial-load　ratio,　aspect　ratio　and　stirrup　characteristic　value　in　the　formula　are　determined　by　a　multiple　regression　analysis.　Considering　the　epistemic　uncertainty　of　the　deterministic　formula,　a　probabilistic　deformation　capacity　model　for　rectangular　RC　bridge　columns　is　developed　based　on　both　the　deterministic　formula　and　the　quasi-static　test　results.　A　case　study　for　a　typical　RC　bridge　column　shows　that　the　probabilistic　model　can　be　applied　to　the　probability-based　and　performance-based　seismic　design　and　the　evaluation　of　bridge　structures.　©,　2015,　Tsinghua　University.　All　right　reserved.