Experimental testing of a friction damped aseismic base isolation system with fail-safe characteristics

An experimental study of a Coulomb friction damped aseismic base isolation system with fail-safe characteristics is described. The base isolation system utilized commercially made natural rubber bearings and a skid system which comes into operation at preset levels of relative horizontal displacement between the structure and the foundations. The fail-safe skid provides hysteretic damping and prevents failure of the isolation system in the event of displacements larger than those assumed in the original design. The isolation system can be designed for an earthquake which can be reasonably expected within the lifetime of the structure; in the event of an earthquake of unanticipated intensity the fail-safe system will prevent collapse of the structure. The implementation of the system in full scale structures poses no technical or construction problems.