Evaluation of FEMA-350 Seismic Provisions for Steel Panel Zones

Steel panel zone design provisions have undergone large changes in the past four decades. The recently introduced FEMA-350 (2000) guidelines are substantially different from previous provisions, and are no longer a function of the plastic strengths of the panel zone and adjoining beams. Rather, they are based on the premise that the framing beams and the panel zone both yield simultaneously to promote controlled inelastic participation of both components. This paper evaluates and discusses the new provisions based on an examination of published test data and the results of transient analyses of buildings with four-, eight-, and sixteenstory moment resisting steel frames. The limited test results reviewed do not confirm the adequacy of the new panel zone provisions and furthermore suggest that panel zone deformation demands could be affected by connection detailing. The frame analysis results show that the FEMA-350 provisions lead to a rather low level of panel zone participation. A discussion of design implications and research needs is provided.