Sudip Chowdhury, Sondipon Adhikari
This paper introduces advanced stiffened amplifier friction sliding isolators (SAFSIs) designed to enhance seismic performance through simultaneous amplification of effective mass and stiffness. These isolators address key limitations of conventional base isolation systems, including high static mass requirements, limited adaptability to varying ground-motion profiles, reduced effectiveness in high-rise structures, inadequate dynamic response attenuation, and the lack of optimal closed-form design guidelines. They also overcome the inability of existing amplifier designs to simultaneously enhance effective mass and stiffness across a broad frequency range, critical for maintaining performance under unpredictable dynamic conditions. The proposed isolators are implemented at the base of both single- and multi-degree-of-freedom systems, i.e., SDOF and MDOF, to effectively suppress structural vibrations. The governing equations of motion are formulated using Newton’s second law, and optimal design parameters are obtained through an H2 optimization technique. Frequency-domain responses, derived using transfer matrix formulations, are validated via time-domain simulations using the Newmark-beta method under near-field earthquake excitations. The results demonstrate substantial vibration reduction, with displacement attenuation of 35.29% for SDOF systems and 55.64% for MDOF systems, highlighting the superior adaptability, energy dissipation capability, and seismic resilience of these novel isolators.