Historical development of friction-based seismic isolation systems

Base isolation has emerged as one of the most effective high-tech strategies for protecting infrastructure under seismic loading. This review paper discusses the historical development of friction-based seismic isolation systems, focusing on systems that have successfully been deployed and used as seismic safety measures for structures located in Europe. The conception and implementation of the Friction Pendulum system, the development of low friction materials and the effects of heating, contact pressure and velocity are discussed in light of past and recent numerical and experimental evidence. The merits of multiple surface devices, namely the Double Curvature Friction Pendulum and the Triple Friction Pendulum are also discussed, along with current knowledge and research gaps. Two European case studies, the Bolu Viaduct and the C.A.S.E. Project, are presented to illustrate that sliding base isolators can be used to meet otherwise unachievable design objectives. Finally, existing problems such as the response to high vertical accelerations, the potential for bearing uplift and the relevance of residual displacement are analyzed.