Seismic performance of post-tensioned steel moment resisting frames with friction devices

A post-tensioned friction damped connection (PFDC) for earthquake resistant steel moment resisting frames (MRFs) is introduced. The connection includes friction devices on the beam flanges with post-tensioned high strength strands running parallel to the beam. The connection minimizes inelastic deformation to the components of the connection as well as the beams and columns, and requires no field welding. Inelastic analyses were performed on a six-story, four-bay steel MRF with PFDCs to study its response to strong ground motions. The PFDC-MRF was designed using a performance based design approach. Results show the MRF with PFDCs has good energy dissipation, self-centering capability, and strength. Variability in the maximum friction forces that develop in the friction devices was determined not to have a significant effect on the MRF performance. The analyses indicate that the seismic performance of a MRF with PFDCs can exceed that of a MRF with conventional moment resisting connections.