<scp>T</scp> heory and experiment of an adaptive sliding isolator with a long-stroke passive variable friction damper

Many studies have shown that friction dampers with adjustable forces are more effective at reducing seismic responses in buildings compared to those with constant forces. However, applying such dampers to seismic isolation systems is challenging due to the large displacement demands of isolation layers. This study proposes a novel adaptive isolation system that combines a sliding isolator with a long-stroke passive variable friction damper. The frictional force of the damper is adjusted passively by the geometry of the friction rod, designed using a cosine function to provide displacement-dependent damping. A theoretical model of the system was developed, and a prototype was fabricated and tested on a shaking table. The experimental results validate the theoretical predictions, demonstrating that the system achieves the desired hysteretic behavior and effectively controls both displacement and acceleration under high-intensity earthquakes. Compared to conventional sliding isolators, the proposed system exhibits superior performance in mitigating seismic responses.