Behavior of ductile SMRFs at various seismic hazard levels

A summary is presented of a comprehensive study on the seismic behavior of ductile steel moment resisting frame (SMRF) structures with fully restrained connections. The study focuses on the seismic behavior of code compliant structures of different heights (3-, 9-, and 20-stories), located in regions of different seismicity (Los Angeles, Seattle, and Boston), and subjected to sets of ground motions representative of various hazard levels (return periods of 72, 475, and 2,475 years). Structural behavior characteristics are illustrated by means of inelastic static (pushover) analysis results. Dynamic performance characteristics are evaluated from story drift demand predictions obtained through nonlinear time history analysis. The sensitivity of the response to analytical modeling is appraised. The performance of the model structures is found to be in fair agreement with general expectations for conventional design events and more frequent earthquake events. For rate events larger than expected inelastic deformations may be experienced and the potential for unacceptable performance is not negligible.