A Numerical Investigation on the Effect of Panel Zones on Cyclic Lateral Capacity of Steel Moment Frames

The seismic response of a steel moment frame (SMF) highly depends on the characteristics of structural members and detailing of connections. It is believed that proper performance of the panel zone significantly contributes to the ductile behavior of special and intermediate moment frames subjected to seismic loads. The main objective of this paper is to study the effect of panel zone on the behavior of moment frames and to investigate whether or not one can ignore panel zones in a finite element model of a steel frame. Through a vast investigation, two models for representing a panel zone were selected. The paper studies the impact of either of these two selected models on the simulated behavior of the same structure. Consequently, a nonlinear rotational spring is used for modeling the behavior of the panel zone. Finally, as a case study, the effects of modeling panel zones in SMFs are investigated. By studying the behaviors of two specific frames, a comparison between computed results obtained by considering different analytical models for the panel zone is presented. It is concluded that the effect of strong panel zones on the overall behavior of a structure is limited.