The newly-developed electromagnetic inertial mass damper (EIMD) consisting of an inerter element and a damping element can significantly enhance the seismic performance of frame structures. However, whether an EIMD can enhance the seismic performance of a base-isolated structure (BIS) remains largely unknown. This paper presents a comprehensive theoretical study of the BIS with an EIMD, stressing on the dynamic behavior, parameter optimization, and seismic performance. Based on a simplified two-degree-of-freedom model, we derive the closed-form solutions of the dynamic characteristic parameters, modal participation factors, and dynamic amplification factors. A parametric study is conducted to investigate the effects of the EIMD parameters on the dynamic behavior of the system, through which the seismic response control mechanism of the EIMD in BIS is comprehensively analyzed. When the BIS subjected to a total of 20 earthquake records, the parameters of the EIMD are optimized for minimizing the interstory drift of the superstructure, the absolute acceleration response of the superstructure, and the relative displacement response of the base floor, individually. The effectiveness of the EIMD in enhancing the seismic performance of base-isolated structures is validated via numerical simulation of a five-story isolated building structure. Under a typical earthquake ground motion, the peak relative displacement of the base floor is reduced by up to 56.57% in comparison to traditional BIS; whereas the peak relative displacement and the absolute acceleration of the superstructure are reduced by up to 60.00% and 52.11%, respectively. Both analytical and numerical results demonstrate that the EIMD can significantly reduce the dynamic responses of both the base floor and the superstructure.
- Base-isolated structure
- Dynamic amplification factor
- Electromagnetic inertial mass damper
- Parameter optimization
- Seismic performance
ASJC Scopus subject areas
- Civil and Structural Engineering