EVALUATION ON DAMAGE AND RESIDUAL PERFORMANCE OF LEAD RUBBER BEARINGS AFTER THE SHAKING TABLE TEST

This paper presents damage and structural performance of lead rubber bearings which experienced shaking table tests on seismic isolation systems. During the shaking table tests, some of the bearings ruptured due to excessive shear deformation. After the tests, failure surfaces were observed to confirm that these failures started at not bond layers but rubber sheets. Static loading tests were conducted on bearings without rupturing to evaluate structural performance before and after the shaking table tests. Then these bearings were cut in the main loading direction to observe inner damage. In addition, test pieces were made from these bearings to perform shear material tests and peeling tests. It was found that, although inner damages of the rubber and steel were observed around lead plugs, fundamental performance of the bearings was less deteriorated even after the shake table tests.