DYNAMIC RESPONSES OF RUBBER COMPOUNDS FOR ANTI-SEISMIC ISOLATORS

The mechanical properties of the elastomers used in the manufacture of seismic rubber isolators are sensitive to mechanical and environmental working conditions, therefore resulting in large variation ranges of the performance of seismic isolation systems installed in buildings and structures. The study investigates the cyclic stress–strain behavior of several elastomer compounds used in the manufacture of anti-seismic rubber bearings. The influence of mechanical and environmental factors, including strain amplitude, number of cycles, frequency, air temperature, and application of concurrent compressive and shear stresses, on the shear properties of the compounds is assessed. The results are analyzed and used to calculate modification factors of design properties for each compound. The variability of the mechanical properties is studied and compared to the requirements on production rubber bearings set in the current European standard on anti-seismic devices