Modeling and characterization of seismic isolation bearings

A coordinated experimental and analytical research program sponsored by the California Department of Transportation is underway to improve knowledge about seismic isolation and supplemental damping for highway bridges. The first phhase of the study is to characterize the bidirectional response of elastomeric and sliding isolation bearings for static and dynamic excitation in a thorough static and dynamic testing program. Analytical models based on classical plasticity and smoothed plasticity (Bouc-Wen) are used for representing bearing behavior. Static biderectional load histories and eartrhquake response studies show the effect of bi-directional coupling in these models compared with independent uni-directional models.(AU)