Structural steel special moment frames often are used as part of the seismic force-resisting systems in buildings designed to resist earthquakes with substantial inelastic energy dissipation. They are one of a few select systems that U.S. building codes permit without restriction in buildings exceeding 160 ft in height, even in the most critical occupancies and in areas mapped as having the highest ground motions. Beams, columns, and beam-column connections in steel special moment frames are proportioned and detailed to resist flexural, axial, and shearing actions that result as a building sways through multiple inelastic displacement cycles during strong earthquake ground shaking. Special proportioning and detailing requirements are therefore essential in resisting strong earthquake shaking with substantial inelastic behavior. These moment-resisting frames are called Special Moment Frames because of these additional requirements, which improve the inelastic response characteristics of these frames in comparison with less stringently detailed intermediate and Ordinary Moment Frames.
Seismic Design of Steel Special Moment Frames: A Guide for Practicing Engineers
December 30, 2009
Publication: NEHRP Seismic Design Technical Brief No. 2, National Institute of Standards and Technology, Gaithersburg, MD
Services: Structural Design