An experimental study was conducted to investigate the seismic behavior of an innovative moment connection for steel moment resisting frames. The connection consists of bolted top and seat angles with post-tensioning strands. The experimental program involved the testing of nine large-scale specimens. Each specimen represented an interior connection, consisting of two wide flange (WF) steel beams attached to a column. Several parameters were investigated in the study. These include the angle leg thickness, angle gage length, beam flange reinforcement plates, connection shim plates, and post-tensioning force. The results of the test program demonstrate that post-tensioned connections possess exceptional cyclic strength and ductility, where yielding occurs in the angles while other structural members remain essentially elastic. The initial elastic stiffness of the connection is comparable to that of a conventional fully restrained connection, with no permanent deformation occurring in the specimen following the application of several inelastic cycles of drift. The angle geometry is shown to influence the connection moment capacity and energy dissipation. Simple design models for estimating connection behavior are presented and compared to the test results.
