To　investigate　the　seismic　performance　of　prefabricated　steel　bridge　piers　with　partially　filled　concrete　(PS-PFC　bridge　piers)　under　reversed　horizontal　loading,　quasi-static　tests　were　conducted　on　four　large-scale　specimens,　with　the　column　base　form　and　concrete　filling　ratio　as　variables.　In　addition,　refined　finite　element　simulations　and　expanded　parametric　analysis　of　these　bridge　piers　were　performed　using　ABAQUS　software.　The　test　results　show　that　when　the　concrete　filling　ratio　is　25　%,　the　bridge　pier　EBD-25　(with　embedded　column　base)　exhibits　strong　hysteretic　performance,　but　suffers　significant　post-earthquake　damage,　rendering　it　difficult　to　repair.　In　contrast,　the　bridge　pier　EB-25　(with　end-bearing　column　base)　demonstrates　excellent　seismic　performance,　with　only　minor　post-seismic　damage,　including　tensile　deformation　of　the　anchor　rods　and　buckling　of　the　base　plate　at　the　ultimate　state,　which　is　easily　repairable.　Variations　in　the　concrete　filling　ratio　have　a　significant　impact　on　the　seismic　performance　of　end-bearing　PS-PFC　piers.　The　failure　of　pier　EB-0　(without　concrete-filled)　is　characterized　by　bulging　and　tearing　of　the　steel　tube　above　the　stiffeners,　whereas　the　failure　mode　of　pier　EB-50　is　comparable　to　that　of　EB-25.　The　parametric　analysis　reveals　that　when　the　concrete　filling　ratio　reaches　a　certain　threshold　(50　%　for　embedded　bridge　piers　and　25　%　for　end-bearing　piers),　further　concrete　infill　has　minimal　effect　on　seismic　performance.　Furthermore,　the　axial　compression　ratio,　steel　strength,　and　other　parameters　influence　the　seismic　behavior　of　PS-PFC　piers　to　varying　extents.　Finally,　theoretical　calculation　methods　for　the　lateral　load　capacity　of　end-bearing　PS-PFC　piers　were　proposed,　showing　good　agreement　with　finite　element　simulation　results.　©　2025　Institution　of　Structural　Engineers