Improving seismic performance using adaptive variable friction systems

Abstract Seismic isolation has been used to effectively protect buildings and bridges from earthquakes. One of the challenges in designing seismic isolation systems is that, many of them can only be designed to optimize their behavior to one targeted level of seismic hazard. When they are designed for rare events, their performance in more frequent events cannot be controlled, which may leads to non-optimal behavior. To address this issue, the Adaptive Variable Friction System (AVFS) was recently introduced, which can be designed to multiple levels of seismic hazard. This paper discusses, first, the mechanics of AVFSs, and a practical method for design. It then presents an extensive parametric study considering realistic structures and several ground motion intensities. It is shown that, when designed to the same performance target for rare events, compared to traditional friction pendulum systems, AVFSs are able to improve superstructure performance at more frequent events. The effect of design parameters on the performance of AVFS-isolated structures is also discussed.