Establishment of Capacity Design Requirements for Cold-Formed Steel — Special Bolted Moment Frames

Design provisions of the Cold-Formed Steel—Special Bolted Moment Frame (CFS—SBMF) system in the proposed AISI Seismic Standard (AISI S110) are developed such that energy dissipation in the form of bolt slippage and bearing in the bolted beam-to-column moment connections would occur during a major seismic event. Beams and columns are then designed following the capacity design principles to remain elastic. Based on the instantaneous center of rotation concept, this paper presents background information for the design provisions in the AISI standard for calculating the expected maximum seismic force in the beams and columns at the design story drift. This requires that the resistance from both the bolt slippage and bearing actions in the moment connection be computed. Design tables are provided to facilitate the design. The recommended seismic design procedure is also provided.