The effects of reduced beam section connections on seismic displacement demands in steel moment frames

Following extensive damage to welded steel beam-to-column moment connections during the 1994 Northridge and the 1995 Kobe earthquakes, analytical studies showed that Brittle fracture is one of the problems of connections in steel structures. Reduced beam section (RBS) moment resisting connections are among the most economical and practical rigid steel connections developed in the aftermath of the 1994 Northridge and the 1995 Kobe earthquakes. Using this type of connection, the plastic hinge will be placed, in a conducted mode, in a specific area in the beam. Among the types ofRBSconnections, is theRBSconnection with reduced by radius section which will be analyzed in this research. Regarding the high impact of drift on building’s damages, we have proceeded with analyzing the effect of reducing the stiffness ofRBSconnections on the increase or decrease of the frame drift. So we have proceeded with a comparison between this type of connection with cover plate. The results of analysis indicated that the fabrication ofRBSconnection will increase the global story drift angle, in comparison with cover plates connections, but as for the inter story drift angle the trend will not be the same and in different stories different behaviours will be observed. For analysis the SAP 2000 software were used and time history analyses were used for investigation.