To　study　the　seismic　performance　of　the　all-steel　buckling-restrained　brace　(BRB)　using　the　novel　soft　steel　LY315　for　core　member,　a　total　of　three　identical　BRBs　were　designed　and　a　series　of　experimental　and　numerical　studies　were　conducted.　First,　monotonic　and　cyclic　loading　tests　were　carried　out　to　obtain　the　mechanical　properties　of　LY315　steel.　In　addition,　the　parameters　of　the　Chaboche　model　were　calibrated　based　on　the　test　results　and　then　verified　using　ABAQUS.　Second,　three　BRB　specimens　were　tested　under　cyclic　loads　to　investigate　the　seismic　performance.　The　failure　modes　of　all　the　specimens　were　identified　and　discussed.　The　test　results　indicate　that　the　BRBs　exhibit　excellent　energy　dissipation　capacity,　good　ductility,　and　excellent　low-cycle　fatigue　performance.　Then,　a　finite　element　(FE)　model　was　established　and　verified　with　the　test　results.　Furthermore,　a　parametric　study　was　performed　to　further　investigate　the　effects　of　gap　size,　restraining　ratio,　slenderness　ratio　of　the　yielding　segment,　and　material　properties　of　the　core　member　on　the　load　capacity　and　energy　dissipation　capacity　of　BRBs.　Copyright　©　2022　Techno-Press,　Ltd.