Earthquake isolator with progressive nonlinear deformability

To protect buildings against strong earthquakes isolating devices, which are introduced between the building and the foundation, can be used. The devices act under external forces as rigid connections and under earthquakes as shock absorbers. A base isolator with hardening behaviour under increasing loading has been developed for medium-rise buildings (up to four storeys) and sites with moderate earthquake risk. Following the construction of the isolator, the behaviour of a prototype has been investigated in the laboratory under dynamic loads. Based on the experimental results the linear equivalent stiffness and damping properties of the device are determined in this paper and a preliminary numerical analysis of the dynamic behaviour of the isolator is investigated for ten actual earthquake motions of the Greek Mediterranean region.