Effects of Deformation Softening on Seismic Behavior of Steel Moment Frames

Abstract eng:
Engineers have become increasingly concerned about the potential effects of various forms of deterioration that may be experienced by moment-resisting frame structures during severe seismic excitations. The brittle connection fractures experienced by a number of welded steel moment-resisting frame structures during recent earthquakes have been the most extensively studied to date. However, recent cyclic testing of beam-column connections into the inelastic range demonstrates that connections may suffer other, more ductile forms of deterioration. Negative post-yield tangent stiffness, hereafter referred to as deformation softening, is of particular interest due to its potentially adverse effects on system behavior. The effects of deformation softening were examined as part of an integrated experimental and analytical investigation of the effects of various forms of hysteretic deterioration on steel moment frame system behavior. The experimental portion of this study consisted of a series of shaking table tests performed on a one-third scale, two-story, one bay, steel moment frame with idealized, mechanical connections. These tests and subsequent analytical studies show that, in general, significant loss of connection strength capacity, whether from deformation softening or other types of deterioration, leads to large peak and residual drifts and, for large pulse excitations with durations longer than the fundamental period of the structure, may cause collapse. Deformation softening was found to have substantial adverse effects on system behavior in many cases.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket