Modeling and seismic collapse resistance study of a steel SC-MRF

A self-centering (SC) moment resisting frame (MRF) is an alternative to a conventional steel special moment resisting frame (SMRF) with welded beam-to-column connections for seismic-resistant steel frame buildings. The beams in an SC-MRF are post-tensioned to the columns by high strength post-tensioning (PT) strands that are oriented parallel to the beams, providing restoring forces to control gap opening at the beam-column interface. Little is known about the collapse resistance of SC-MRFs under extreme seismic ground motions. Incremental Dynamic Analyses (IDA) are performed to determine the collapse margin ratio of a 4-story low-rise steel building with perimeter SC-MRFs. The structural model for the SC-MRF for the IDA includes shell finite elements to enable important limit states, including local buckling in the beams, to be included in the analyses. The results from the IDA show that the collapse resistance of an SC-MRF system is comparable to that of a conventional steel SMRF.