Experimental Studies on a Combined Damper for Repairable Steel Moment Connections

Steel structures are among the building systems extensively used in most countries. They have been the subject of numerous studies with the aim of optimizing their performance under vertical and lateral loads. One important issue in this regard is reparability of connection areas under severe earthquakes, i.e., developing connections easy to be restored to their initial state. In this paper a passive control system recently developed by the authors is studied further and enhanced in configuration and behavior. The developed system is a repairable part of the connection zone in a steel moment frame absorbing the seismic damage and producing hysteretic damping. This damper is a rubber-steel core added beneath the beam-to-column connection. The steel bolts core provide for the hysteretic damping and the rubber layer contributes the restoring force. Results of several cyclic tests by varying different parameters of the damper are presented and discussed in this paper.