Influential Factors in Pinch Effect and Energy Dissipation of the Kaiser Bolted Bracket Moment Connection

In the aftermath of the 1994 Northridge، California، earthquake. A significant number of steel moment resisting structural systems were damaged. Many studies and researches have been conducted to improve the seismic performance of structures after the catastrophe. One of the proposed connections for special moment-resisting frames included AISC-358 is Kaiser bolted bracket moment connection، briefly named، KBB، this brackets produced as high steel cast. In this study، the seismic behavior of moment connection، KBB is examined under standard loading history and near-fault loading history according to ATC and FEMA codes. The results show that the connection has suitable seismic performance. But in beams with high depth due to the bracket rigidity، there is high lever force in top row bolts. Moreover use of Finger shims with variable thickness، reduce pre-tensioned force in bolts and increase pinch in hysteresis curve specimens.