This　paper　proposes　a　novel　seismic　resilient　knee　braced　frame　(KBF)　and　focuses　on　seismic　performance　evaluation　and　design.　In　this　novel　system,　the　shape　memory　alloy　(SMA)　knee　braces　(KBs)　and　replaceable　energy-dissipating　(RED)　connections　are　the　key　components.　The　SMA　KBs　mainly　provide　self-centering　ca-pacity,　and　the　RED　connections　mainly　offer　energy-dissipating　capacity.　To　reveal　the　seismic　performance　characteristics,　the　3-and　6-story　KBFs　are　selected　as　the　example　structures.　The　proposed　systems　are　designed　by　a　modified　performance-based　plastic　design　method,　which　distributes　the　seismic　energy　to　the　SMA　KBs　and　the　RED　connections　by　defining　an　energy　distribution　factor　p.　In　what　followed,　nonlinear　static　and　nonlinear　time　history　analysis　are　conducted.　It　indicates　that　these　systems　could　well　meet　the　prescribed　performance　targets,　although　they　are　designed　using　different　p　values.　In　current　work,　the　potentially　optimal　p　value　is　found　to　be　0.1,　which　represents　the　case　where　10%　of　seismic　energy　is　allocated　to　the　SMA　KBs.　The　advantages　of　the　novel　KBF　are　twofold:　1)　the　consumption　of　SMA　material　is　significantly　reduced,　because　the　RED　connections　are　the　major　damping　source;　2)　the　damaged　RED　connections　can　be　conve-niently　repaired　or　replaced,　because　the　frames　could　nearly　return　to　original　position,　owing　to　the　SMA　KBs.