Abstract
The use of laminated rubber bearings for bridges have been recommended to employ after the 1995 Kobe Earthquake, and the number of bridges designed with the laminated rubber bearings by a design earthquake (Level 2) has been increasing. It was observed during the 2011 Great East Japan Earthquake that some of those laminated rubber bearings in exiting bridges suffered intensive damage including rupture and cracking. Because these laminated rubber bearings were uninstalled from the bridges for the replacement, authors conducted a series of tests for uninstalled bearings to examine the effect of the seismic damage or the aging on properties of the bearings or the material. Test results show that the stiffness of the uninstalled bearings with the damage was increased and the damping property was reduced. Stable hysteresis loop was observed in some rubber bearings, while premature rupture was observed in some rubber bearings at the shear strain of less than 250%.
