Seismic Performance of Steel Self-Centering, Moment-Resisting Frame: Hybrid Simulations under Design Basis Earthquake

The behavior of a self-centering moment-resisting frame (SC-MRF) is characterized by the connection gap opening and closing at beam-column interfaces under earthquake loading. A SC-MRF uses high-strength posttensioning strands to precompress the beams to the columns and to close the gaps that develop under earthquake loading, returning the frame to its initial position (i.e., the frame is self-centering). In this study, a beam web friction device is included in each beam-column connection to dissipate energy under seismic loading. Unlike a special steel moment-resisting frame with welded connections (W-SMRF), a SC-MRF can be designed to survive the design basis earthquake (DBE) without structural damage, leading to the potential for immediate occupancy performance, and to suffer only modest damage under the maximum considered earthquake, leading to collapse prevention performance. A 7-bay, 4-story SC-MRF prototype building was designed for a location in the Los Angeles area. A 0.6-scale model of two bays of the SC-MRF building was constructed in the laboratory and subjected to simulated earthquakes using the hybrid simulation method. This paper focuses on the DBE-level performance of this SC-MRF. DBE-level simulation results and performance evaluations are presented. The behavior of the SC-MRF is compared with that of a W-SMRF using nonlinear pushover analysis results.