History of Special Moment Frame Development

Traditionally, special steel moment frames are designed so that the beam will yield under large displacement. The yielding of the beam section provides energy dissipation and is designed to ensure the beam-to-column connection is not compromised. The current design philosophy is the product of extensive testing of SMF connections from the findings of the 1989 Loma Prieta and 1994 Northridge earthquakes in California. Figures 1, 2 and 3 are test specimens showing yielding at designated areas of the beam.

Figure 1 — Formation of Plastic Hinge at RBS Connection
(Reference: Gilton, Chi and Uang, UCSD SSRP-2000/03)

Figure 2 — Fracture of Beam Flange Plate Moment Connection
(Reference: Sato, Newell and Uang, UCSD SSRP-2007)

Figure 3 — End Plate Specimen at Failure
(Reference: Sumner et al. 2000)