EVALUATION OF RESIDUAL SEISMIC PERFORMANCE OF RUBBER BEARINGS EXPERIENCED LARGE DEFORMATIONS BASED ON CYCLIC LOADING TESTS

Abstract

 Couple of rubber bearings on highway bridges were damaged by 2011 Tohoku Pacific Offshore Earthquake. Even though the seismic design using the rubber bearings has been widened since 1995 Kobe Earthquake, the residual seismic performance of the rubber bearing which were experienced great earthquakes as like the above great earthquakes has not been identified. In this study, in order to investigate the residual seismic performances of Rubber Bearings (RB), Lead Rubber Bearings (LRB) and High Damping Rubber-super (HDR-S), load-displacement hysteresis, equivalent stiffness, equivalent damping, cyclic loading tests using 3 test pieces per each type of rubber bearing were conducted. No. 1 was subjected to axial force with 6MPa and 100 cycles lateral loadings with shear strain of 250%. No. 2 was subjected to the axial force with 1MPa and 100 cycles lateral loadings with the shear strain of 250%. No. 3 was subjected to the axial force with 6MPa and 100 cycles lateral loadings with the shear strain of 150% and the axial force with 6MPa and 10 cycles lateral loadings with the shear strain of 250%.