Experimental Investigation of Reduced Beam Section Connections by Use of Web Openings

Since the 1994 Northridge Earthquake, a wide variety of different moment connections have been developed to provide high ductility and reliable performance. Most of these moment connections incorporate the reinforcement at the connection using cover plates, ribs or haunches (Engelhardt, Sabol, Aboutaha, and Frank, 1995; Engelhardt and Sabol, 1998; Uang and Bondad, 1996; Uang, Bondad, and Lee, 1998; Whittaker and Gilani, 1996). The purpose of the reinforcement at the connection was to force the plastic hinge away from the face of the column, where premature fractures can occur due to potential weld defects, stress concentrations, etc. The reinforced connections generally showed good performance. However, reinforcing the connection may increase its fabrication costs. Moreover, there were some concerns with respect to reliability resulting from the very large weld for reinforcement. A total of six large-scale tests were performed on single cantilever type test specimens. The specimens were subjected to slowly applied cycles of loads. A test program was conducted on Reduced Beam Section connections by use of beam web openings. The test specimens showed good performance overall, although yielding occurred at lower levels of rotation and strength degradation was worse than for reduced beam flange type connections (dogbone connections).