Experimental Evaluation of Various Dependencies in the Reduced and Full-Scale Natural Rubber Bearing

The full-scale dynamic seismic isolation testing facility (E-Isolation) newly constructed in March 2023 at Hyogo prefecture, Japan. This testing facility employs a system that is possible to conduct experiments on full-scale specimens that subject them to large deformations dynamically. In this paper, the analysis is based on natural rubber bearings with a wide range of comparative studies ranging from 300 mm to 1200 mm rubber diameter. In conducting the experiments, the reduced-scale specimens with 300 mm diameter and the full-scale specimens with 650 mm diameter are tested using a two-stage loading apparatus, and the full-scale specimens with 800 mm and 1200 mm diameter are subjected to horizontal loading experiments in E-Isolation. It was found that natural rubber bearings show highly linear structural behavior including extremely small amplitude region of less than 10% shear strain and dependence of compressive stress, deformation amplitude and frequency on horizontal stiffness in reduced-scale to full-scale specimens.