Modeling strategies for the lateral response of curved surface slider devices under extreme displacement demands

Base isolation represents one of the most efficient strategy for the reduction of the structural vulnerability of buildings and bridges. Design procedures generally aim to provide the proper period shift, in order to reduce spectral acceleration values and, consequently, the base shear and internal forces. On the other hand, high displacement demands can be achieved, which can be partially limited by providing dissipative capacity through hysteretic behaviors. Although design procedures allow to fairly estimate the design displacement of the adopted devices, extreme seismic event can occur, and displacement higher than the design value can be experienced. Especially for Curved Surface Slider devices, if the displacement demand exceeds a certain geometrical limit, non-negligible damage can occur at the sliding pad, and variations in the force response are consequently noticed. In this work modeling strategies for the computation of the seismic response of base-isolated buildings are presented, by considering extreme earthquake loading conditions. Analytical models are reported for Curved Surface Slider devices, calibrated through the experimental outcomes of tests performed at the Laboratory of EUCENTRE Foundation in Pavia (Italy). In addition, simplified dynamic systems are defined, which allow fast assessments of the global response of a base-isolated structure, even though extreme seismic events are applied. Results have been compared to the response returned by an experimental hybrid simulation, in order to evaluate the accuracy of the presented dynamic systems.