FE modeling of a seismic isolator made of HDR and regenerated EPDM

Abstract

Losses and damages induced by strong earthquakes are a dramatic reality worldwide. As a consequence, the implementation of innovative protection strategies for both existing and new constructions is of key societal importance. Elastomeric isolators are special devices for seismic isolation of structures. Typically, they are made of alternate layers of steel or fiber reinforced laminas and rubber and they are interposed between the ground and the foundation in order to increase the natural period of the structure and reduce the inertia forces to apply in case of an earthquake. This study proposes a detailed 3D FE modelling of isolators conceived for low-rise masonry buildings in developing countries, carried out through the FE software code Abaqus. The isolator under study consists of an energy dissipation core made by relatively High Damping Rubber and an external EPDM ring. In addition, in order to reduce the production cost and allow its applicability in developing countries, it presents unbonded boundary conditions. In fact, the upper and lower edges do not exhibit any bond with the supports. The main feature of such a device is the large deformability thanks to the rollover deformation and the favorably lower lateral stiffness compared to the bonded isolator.