Rotational viscoelastic dampers for steel buckling-restrained braced frames: Concept, validation, and evaluation

A new type of rotational viscoelastic damper (RVED) was proposed to effectively increase the levels of inherent damping of the steel buckling-restrained braced frame (SBRBF). The proposed RVEDs are installed in lieu of the existing beam-column connections, which requires no additional architectural space. Moreover, different from the buckling-restrained braces, energy dissipation of the RVEDs are immediately activated against all levels of wind-and/or earthquake-induced ex-citations. In this paper, the proposed RVED was experimentally evaluated after a detailed introduction of the damper mechanism. The performance of the proposed RVED was experi-mentally validated in the first part of the study. Then, verifications of the damper effectiveness within the SBRBFs were presented. Numerically, for six different four-story SBRBFs with and without the RVEDs, large rotated angles at the beam-column joint level were observed when the inter-story drift ratio of the SBRBFs was close to 2%. The RVEDs could provide an added system damping of approximately 3%, whose benefits were demonstrated in the study. Furthermore, one of the six SBRBFs was selected as a case study to reveal the structural performance with the RVEDs against earthquakes. With the added damping, the average peak story displacement, story acceleration, and story shear against the frequent earthquakes were reduced by 34.56%, 27.96% and 43.35%, respectively. When against the rare earthquakes, the three average peak responses were reduced by 9.68%, 12.15% and 14.90%, respectively.

Automated summary

A new type of rotational viscoelastic damper (RVED) was proposed to effectively increase the levels of inherent damping of the steel buckling-restrained braced frame (SBRBF). The proposed RVEDs are installed in lieu of the existing beam-column connections, which requires no additional architectural space. Moreover, different from the buckling-restrained braces, energy dissipation of the RVEDs are immediately activated against all levels of wind-and/or earthquake-induced ex-citations.