The Simpson Strong-Tie® (SST) Strong Frame® moment connection is a partially restrained (Type PR) connection that uses a modified shear plate connection (single-plate shear connection) for shear transfer and a modified T-stub or end-plate connection (the Yield-Link® structural fuse) for moment transfer, as shown in Figures 12.1(a) and 12.1(b). The central bolt in the vertical line of bolts in the shear plate uses a standard bolt hole and defines the center of rotation for the joint, while the rest of the bolt holes are slotted to allow rotation of the beam around the central bolt. Matching holes in the beam web are all standard holes. This prevents moment transfer through the shear plate connection. The central bolt and all horizontally slotted shear plate bolts participate in shear resistance. The central bolt is also designed, together with the additional horizontally aligned bolts, to resist the axial force in the beam at the connection. The modified T-stub and end-plate link connections, which bolt to both the beam flange and column flange, are configured as yielding links and contain a reduced yielding area in the stem of the link that is prevented from buckling in compression via a separate buckling restraint plate. The connection is based on a capacity-based design approach, wherein connection response remains elastic under factored load combinations, and seismic inelastic rotation demand is confined predominantly within the connection with little, if any, inelastic behavior expected from the members.
Loading…