Friction　dampers　are　widely　used　energy　dissipators　for　the　seismic　fortification　of　engineering　structures,　due　to　their　efficiency,　reliability,　and　cost-effectiveness.　Since　the　friction　force　is　proportional　to　the　normal　load　applied　on　the　sliding　interfaces　for　given　friction　materials,　increasing　the　applied　normal　load　is　always　the　only　approach　to　enhance　the　energy　dissipation　capacity　of　friction　dampers.　However,　a　large　applied　normal　load　may　result　in　serious　wear　problems　at　the　interfaces,　which　in　turn　affects　the　functionality　of　the　damper.　To　address　the　above　issue,　a　novel　rotary　amplification　friction　damper　(RAFD)　is　proposed　in　the　present　study,　which　can　realize　several　times　amplified　friction　force　for　a　given　normal　load　due　to　the　adopted　amplification　system.　The　conceptual　design　and　working　mechanism　of　the　proposed　RAFD　are　first　introduced.　Subsequently,　a　damper　prototype　was　manufactured　and　experimental　studies　were　carried　out　to　examine　the　behaviors　of　RAFD.　Then,　a　nonlinear　mechanical　model　considering　the　gap　between　the　gear　and　rack　is　developed　based　on　the　experimental　results.　Finally,　an　analytical　model　of　a　single-degree-of-freedom　(SDOF)　system　equipped　with　RAFD　is　established　to　investigate　the　control　performance　of　RAFD　in　reducing　the　structural　seismic　responses　and　evaluate　the　influences　of　various　parameters　including　gap　and　earthquake　types　(far-field　and　near-field　ground　motions).　The　analytical　and　experimental　results　demonstrate　that　the　proposed　RAFD　showcases　superior　seismic　control　effectiveness　compared　to　the　traditional　friction　damper;　the　presence　of　a　gap　would　reduce　the　control　effectiveness　of　RAFD　to　some　extent,　while　earthquake　types　have　minimal　impact.　©　2024