Influential Factor in Improving the Seismic Performance of the Kaiser Bolted Bracket Moment Connection

Following the Northridge earthquake of 1994, a significant number of steel moment resisting structural systems were damaged. Several studies have been conducted to improve the seismic performance of steel structures and specially their beam-to-column connections. One of the proposed connections for special moment-resisting frames included AISC-358 is Kaiser bolted bracket moment connection, briefly named, KBB. The brackets in these connections are precast steel elements. In this study, the seismic behavior of moment connection KBB has been examined under standard loading history and near-fault loading history according to ATC and FEMA codes. The results show that KBB connection has acceptable seismic performance except for deep beams. In deep beams a high prying force may occurs in upper rows of the bolts. the main reason for such phenomenon is rigidity of the bracket. Moreover use of Tapered Wedge Shims reduces pre-tensioned force in bolts and increases pinch in hysteresis curve of specimens.