Abstract
Rupture of isolators should be prevented in view of post-earthquake repair time and cost. In this study, effects of strength ratio variation between isolators and reinforced concrete columns due to deterioration of isolators on the seismic failure modes of isolated bridges were investigated considering uncertainties in the material and mechanical properties of isolated bridges. As a result, it was shown that it is important to set the strength at hardening initiation of the isolator to be larger than the ultimate strength of the column in the seismic design to maintain seismic safety of bridges with deteriorated isolators. It was also indicated that rupture strain of isolators is a major uncertainty in evaluating the ultimate failure modes of bridges with deteriorated isolators.
