Numerical assessment of the seismic performance of sliding pendulum isolators

The dynamic properties of sliding pendulum isolators employed for the seismic protection of building and structures are governed by the radius of curvature and the coefficient of friction of the sliding surfaces. A major issue concerns the heat generation occurring at the sliding interface during repeated cycles and the effects of the consequent temperature rise on the properties of the sliding materials. Typically, the coefficient of friction reduces with the increasing of temperature causing a deviation of the stiffness and damping characteristics of the isolation unit from their design value. A finite element model of sliding pendulum isolators is now presented; both its thermal and mechanical outputs have already been validated through comparison with experimental tests. The aim of this work is to show the potentialities of this design tool in predicting the isolator behaviour during qualification tests according to principal codes (EN 15129 and AASHTO).