Abstarct: After the 1994 Northridge earthquake many common connections beam to column were brittle failures. Connection is reduced to improve the performance of these connections was proposed. RBS connections with local reduction in cross section in the vicinity of the focus column prevent the stress concentration at the junction block and place a plastic hinge near the connection point of the column in taken from beam. RBS type of connection known as connection bone (Dogbone) where the arc of circle to cut the wings of beam has been a very good performance against seismic loads is shown. The study examined various aspects of cutting the connection and according to the criteria considered optimal binding geometry was chosen as the best cutting geometry.