رفتار غيرخطي قابهاي فولادي با اتصالات توام صلب و نيمه صلب شكل پذير تحت تاثير زلزله

Seismic Nonlinear Behavior of Moment Resisting Steel Frames With Mixed Rigid Ductile Connections

Seismic behavior of steel frames is affected by dynamic and static behavior of frames connections. One of the reasons for not using MR steel frames with semi-rigid connections in seismic areas has been the possibility of large displacements and instability of the structure. In this paper, seismic nonlinear behavior of moment resisting steel frames with mixed rigid and semi-rigid ductile connections is studied. For this purpose, the seismic nonlinear behavior of steel frames with 3, 4 and 6 spans, and 1, 3, 5, and 8 stories with 4 different forms of mixed rigid and semi-rigid connections and five different initial connection stiffness including zero and infinite stiffness. Under Naghan, Tahas and Elcentro earthquakes are analyzed. Maximum transverse displacements, framesmain period. Maximum base shear force, hysteresis behavior of connection, ductility demands of frames, and time history of transverse displacement are evaluated. The results show that it is possible to design moment resisting steel frames with particular forms of mixed use of rigid and semi-rigid connections so that under earthquake forces, resulting base shear and displacements be less than those in similar rigid frames.