Seismic demand-oriented design of hybrid base-isolated building with the tuned inerter eddy current damper

A novel tuned inerter eddy current damper (TIECD) is proposed to mitigate isolator deformation in a base isolation (BI) system subjected to earthquake ground motions. Considering the topological similarity and damping equivalent criteria, the design formulations of the tuned inerter damper are extended to determine the optimal parameters of the TIECD. A combination of iterative updating, response-spectrum analysis, and complex complete quadratic-combination measures is established to realize the seismic demand-oriented design framework of the TIECD. Furthermore, the proposed design framework incorporates the equivalent stiffness and damping of a lead rubber bearing to approximate the design parameters of the TIECD in a nonlinear BI system. Finally, the feasibility and effectiveness of the designed TIECD are validated using a nine-story base isolated benchmark model with lead rubber bearings. Numerical simulation results indicate that the designed TIECD can significantly suppress the displacement, acceleration, and base shear demands of the hybrid BI system. Compared with the viscous damping in the tuned inerter damper, the designed TIECD exhibits a significantly enhanced level of damping owing to the combination of a lower damping force and a larger deformation.