Quantification of energy dissipation demand for buckling-restrained braces

Buckling-Restrained Braces (BRBs) have been frequently used as stable energy dissipation devices for seismic applications. Currently, the performance of the BRBs is validated using displacement-based loading protocol, which does not account for the energy dissipated by the BRBs. In this paper, a novel procedure is proposed to quantify the energy demand for BRBs at different stories and sites. Hence, the BRB can be tested in the laboratory to ensure that sufficient energy can be dissipated. The proposed method uses the site-specific target spectrum to quantify the earthquake energy for the structures equipped with BRBs. In addition, new quantification factors, including the rise time for the energy dissipation and story-wise modification factor are proposed. The proposed quantification factors are obtained from a large array of time history analyses for a range of structures. The proposed method was verified on a 5-story prototype model equipped with BRBs. The results show that the proposed procedure can estimate the energy demand of BRBs with a reasonable accuracy, and can be used as a reliable method to predict and quantify the energy dissipation demand for BRBs.