Effective Modeling of Special Steel Moment Frames for the Evaluation of Seismically Induced Floor Accelerations

Nonlinear time-history analysis is becoming a standard procedure for evaluating the seismic performance of structures. The current ASCE 7-16 allows practitioners to perform it when the acceleration demands of nonstructural components (NSCs) are required. However, the code in this version omits any suggestion regarding the methodology that should or could be used to represent the structure as a mathematical model. This investigation evaluated the acceleration demands in rigid and flexible nonstructural components using five different assessment methodologies that vary from a detailed concentrated and distributed plasticity model to a very simple model. Nonlinear static and dynamic analyses were performed on 2-, 4-, 8-, 12- and 20-story special steel moment frames to evaluate the effects that mathematical models have on the structurés seismic response and acceleration demands on NSCs. Although results showed that detailed models are the only ones that adequately can capture structure drift deformations, it was found that even the simplest nonlinear model evaluated the acceleration demands correctly in NSCs.