Posttensioned energy dissipating connections for moment-resisting steel frames

The seismic performance of a posttensioned energy dissipating (PTED) connection for steel frames is investigated analytically and experimentally. The PTED connection incorporates posttensioned high-strength bars to provide a self-centering response along with energy dissipating bars that are able to yield in axial tension and compression. The analytical study involves the development of an equivalent iterative sectional analysis procedure to predict the moment-rotation relationship of the PTED connection. Based on this analytical model, a simple design procedure for PTED connections is described. In the experimental study, a cyclic component test was performed on two energy dissipating bars and a cyclic test was conducted on a large-scale exterior beam-to-column PTED connection. The results of the tests show that the PTED test specimen was able to undergo large inelastic deformations without any damage in the beam or column and without residual drift. The proposed analytical model and design procedure were also validated against the experimental results.