Experimental Behavior of Rigid and Semirigid Steel Frames under Cyclic Loading

In order to investigate the influence of connection initial rotation stiffness on the hysteretic behavior of rigid and semirigid steel frames, six one-bay two-story frame models with three types of beam-to-column connections were tested under cyclic loads. Test results showed that frames with higher connection rotation stiffness, such as welded connections, or extended end-plate connections, exhibited sufficient ductility, better load carrying capacity, and more stable hysteretic behavior. The plastic deformation was mainly resulted from the shear deformation of panel zones and the bending deflections at beam end adjacent to column. For frames with lower connection stiffness, such as bolted angle connection, the load carrying capacity and the ductility were much lower than the former. The plastic deformation mainly resulted from the column feet and the top-seat angles of connections. So it is necessary to ensure adequate connection stiffness to obtain good seismic performance of steel frames.