Mechanical behavior of a suite of elastomers used for seismic base isolation

Several practical systems have been developed to protect structures and their contents from the potential devastating consequences of earthquakes. The use of seismic isolation has recently proven to be an effective means to mitigate earthquake damage. With seismic isolation, the structures are decoupled from the strong horizontal ground accelerations. The use of high damping elastomer, steel lamiriated seismic isolation bearings has been proven to be an effective method for seismic base isolation. This paper describes recent research conducted at Argonne National Laboratory to find the mechanical response characteristics of a suite of elastomers compounded for use in elastomeric seismic isolation bearings. The response characteristics were obtained by testing small coupons of each elastomer in a high precision dynamic testing machine. Specifically, the paper reports on tests performed to find the variations in stiffness and energy dissipation with strain level, loading rate, and cycle number. The paper also reports on the effects that strain level has on stiffness recovery