An　innovative　type　of　bolted　beam-to-column　connection　by　means　of　a　-shaped　connector　welded　by　two　flanges,　one　web　and　one　end-plate　is　put　forward　in　this　study.　Besides　standard　bolt　holes,　short-slotted　bolt　holes　are　considered　in　the　flanges　and　web　of　the　connector　for　the　-shaped　bolted　connections.　An　experimental　investigation　of　six　-shaped　bolted　connections　with　the　parameters　of　slotted　bolt-hole　sizes　and　treatment　methods　of　the　faying　surfaces　between　the　-shaped　connector　and　the　beam　and　two　comparative　connections　under　cyclic　load　was　undertaken　to　provide　insight　into　the　cyclic　behavior　of　this　joint　type.　The　results　demonstrate　that　the　presented　-shaped　connections　are　characteristic　of　large　plastic　rotation,　good　ductility,　and　high　energy　dissipation,　meeting　the　seismic　design　provisions　for　stiffness,　resistance,　rotation,　and　ductility.　A　slightly　slotted　size　of　the　bolt　holes　in　the　connectors　can　greatly　improve　the　seismic　performance　of　connections　in　terms　of　the　rotation　capacity,　ductility,　and　energy　dissipation,　and　consequently　prevent　or　reduce　the　risk　of　local　damage　progression　in　the　beam　flanges　and　web　through　the　small　movement　allowed　for　the　beam　end.　This　can　increase　the　postearthquake　reparability　of　steel　structures　with　such　connections.　Treatment　methods　of　the　surfaces　just　affect　the　slip　resistance,　the　corresponding　displacement,　and　therefore　the　ductility　of　connections.　Observations　of　test　connection　specimens　show　that　the　-shaped　bolted　connections　have　multiple　failure　modes　and　can　be　viewed　as　a　combination　of　end-plate　and　T-stub　connections.　Based　on　this,　a　reliable　and　conservative　formula　for　prediction　of　rotation　capacity　of　this　joint　type　is　proposed.　©　2019　American　Society　of　Civil　Engineers.