Seismic performance factors for moment frames with steel‐concrete composite columns and steel beams

Summary Steel‐concrete composite moment frames have been shown to be an effective alternative for use as the primary seismic force‐resisting system of building structures. However, little data are available to justify the structural system performance factors (i.e.,R,Cd, and Ωo) given in codes to characterize the overstrength and ductility of these systems. Reasonable values for these factors are vital for successful seismic design. Based on a suite of new finite element formulations, this work investigates the behavior of composite special moment frames under seismic loading and develops rational system performance factors according to the Federal Emergency Management Agency P695 methodology. A set of archetype frames, selected to be representative of the range of frames seen in practice, were designed according to current design specifications. Nonlinear static pushover and dynamic response history analyses were performed on the frames to generate the statistical data on the seismic response from which the performance factors are quantified. The results from this investigation enable a better understanding of the variability in collapse performance of composite frame systems and will facilitate more effective designs of these systems. Copyright © 2016 John Wiley & Sons, Ltd.