The　probability　of　bridge　piers,　particularly　cast-in-place　hollow　ultra-high　piers　(CIPUHPs)　and　precast　hollow　ultra-high　piers　connected　with　grouted　sleeves　(PCUHP-GSs),　being　impacted　by　falling　rocks　has　increased　significantly　in　mountainous　areas.　In　this　study,　two　1/20-scale　hollow　ultra-high　pier　(UHP)　specimens　were　designed　and　manufactured　to　conduct　impact　tests　using　a　pendulum　system.　The　UHPs　under　longitudinal　impact　were　compared　and　analysed　in　terms　of　the　failure　mode　and　dynamic　response.　On　this　basis,　a　numerical　study　was　conducted　on　continuous　rigid-frame　bridges　with　hollow　ultra-high　piers　(CRFB-UHPs).　The　results　show　that　both　the　CIPUHP　and　PCUHP-GS　exhibit　flexural　failure　at　the　impact　point,　but　the　grouted　layer　and　grouted　sleeve　joints　in　the　PCUHP-GS　remain　as　weak　interfaces　under　impact.　Under　the　same　impact　velocity,　the　CIPUHP　and　PCUHP-GS　exhibit　the　same　impact　force,　owing　to　the　unchanged　local　stiffness　at　the　impact　point.　However,　the　PCUHP-GS　exhibits　greater　deformation　than　the　CIPUHP.　Moreover,　the　energy-dissipation　ratios　are　smaller　for　the　CIPUHP　bridge　(69.3　%)　than　for　the　PCUHP-GS　bridge　(75.3　%),　owing　to　cracking　in　the　grouted　layer.　The　bending　moment　at　the　grouted　layer　in　the　PCUHP-GS　bridge　is　also　smaller.　In　addition,　the　proposed　simplified　numerical　model　of　the　CRFB-UHP　can　achieve　an　87.5　%　improvement　in　computational　efficiency　and　can　be　used　in　a　parametric　study　on　the　impact　performance　of　CRFB-UHPs.　The　parametric　study　results　show　that　increasing　the　longitudinal　reinforcement　and　stirrup　ratios　can　effectively　reduce　deflection　and　local　damage　at　the　impact　point.　An　excessively　large　axial　load　ratio　may　aggravate　reinforcement　buckling　and　increase　deformation　at　the　impact　point,　whereas　increasing　the　interface　failure　strength　of　the　PCUHP-GS　can　reduce　residual　displacements　at　the　impact　point.　©　2024