High damping curved surface sliding isolators for bridges

n this study, material characterization and full-scale assessment of a curved surface sliding isolator with high damping capacity for a viaduct structure have been conducted to investigate its effectiveness and durability. Characterization tests conducted on the PTFE composite used as the sliding surface confirm the durability of the material with no significant deterioration of the coefficient of friction after more than 2400 m of sliding. Prototype tests performed on the isolator show its ability to provide high damping capacity at seismic velocities, and to accommodate slow service movements of the structure with minimum resistance. Despite of the large energy dissipation and relevant temperature increase, the isolator behaves stably during cyclic loading, with variations of stiffness within 10% and damping within 20% with respect to the design values. The proposed design and the advanced PTFE composite are promising in terms of upgrading the seismic resistibility of bridge structures under near-fault motion.