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The self-centering energy-dissipative (SCED) brace is an innovative cross brace for buildings that provides a nonlinear response with good energy dissipation and postyield stiffness while minimizing residual drift after an earthquake. This provides a high level of seismic performance by allowing structures to remain operational even after major seismic events. Recently, the SCED brace has been improved through the design and experimental evaluation of a high-capacity SCED (HC-SCED) that has an axial capacity similar to some of the largest available conventional cross braces for buildings. This prototype HC-SCED satisfied testing protocols for buckling-restrained braces and exhibited full self-centering behavior during cycles up to 1.5% drift. To characterize the hysteretic response of the brace in detail, a new analytical approach is developed. This new approach is necessary because simplified stiffness estimates do not provide good predictions of the low-amplitude displacement response and initial effective stiffness that was measured in the full-scale experiments. The proposed analytical approach includes the effects of fabrication tolerances, which have been identified as the main reason for incorrect low-amplitude displacement predictions that result from the simplified stiffness estimates. Using the results from the HC-SCED tests, the new analytical approach provided good estimates of the initial stiffness of the braces and also was able to predict the behavior of the brace well under a larger fabrication tolerance scenario. These improved predictions may be used to improve the characterization of the effective hysteretic behavior of actual SCED braces for use in nonlinear time history analyses.
Erochko et al. (Mon,) studied this question.