POST-TENSIONED MOMENT CONNECTIONS WITH A BOTTOM FLANGE FRICTION DEVICE FOR SEISMIC RESISTANT SELF-

New earthquake-resistant structural steel moment resisting frame (MRF) systems are being developed by a research group led by Lehigh University in collaboration with Princeton and Purdue Universities under the NSF funded Network for Earthquake Engineering Simulation Research (NEESR) program. These innovative self-centering (SC) structural systems are designed to be damage-free under the design basis earthquake (DBE). This paper presents the results of experimental studies on a post-tensioned friction connection for a self-centering moment resisting frame (SC-MRF). The connection consists of a friction device placed below the beam bottom flange, in order to avoid interference with the composite slab, with post-tensioned high strength strands running parallel to the beam. Tests on the connection show it to possess excellent deformation capacity, minimize inelastic deformations in other elements of the connection, and return the structure to its pre-earthquake position. The results of the experimental studies are presented. Based on the experimental results, analytical models were developed in OpenSees. The formulation for these and a comparison with the experimental behavior of the connection are presented