SLIDING ISOLATION BEARINGS WITH HIGH DAMPING CAPACITY

A key element in the design of seismic isolation systems employing sliding bearings is the choice of the optimal value of the coefficient of friction. Large values of friction provide high damping capacity, but promote huge generation of heat and increase in temperature at the sliding interface, which in turn affect the properties of the friction materials. The performance of a pendulum isolation system employing a composite material made of a PTFE matrix with metal fillers to enhance thermal conductibility and mechanical strength is assessed in the present study. The sliding behavior of the material is investigated in small scale tests and the coefficient of friction is determined at velocities between 100 and 400 mm/s. Finally the wear endurance of the material is evaluated with respect to international codes’ prescriptions. Prototype tests performed on real scale devices show a fair flexibility to accommodate slow movements and confirm the high damping capacity and good stability of dynamic properties of the isolation system over prolonged times of loading at velocities in the seismic range. The composite material is able to withstand repeated loading and high temperatures without failure