Reduced-Scale Dynamic Loading Tests on Seismic Isolation Bearing Excluding Friction and Inertia Forces

Seismic isolation bearing test facilities typically consist of moving horizontal platens under high compression. However, these dynamic moving platens inevitably lead to friction and inertial forces generated by large vertical loads and inertial forces due to the dynamic mass action of the moving platen, which ultimately affects the accuracy of the measured force. To solve this problem, the authors have proposed a direct reaction force measurement system (horizontal-vertical separated type), which can eliminate the contamination of friction and inertial forces. The measurement of pure reaction forces without the contamination of friction and inertia is crucial for the reliability of test results. In this paper, prior to the construction of the large-scale facility of E-Isolation, which was completed in March 2023, reduced-scale mock-up dynamic tests were conducted using the proposed measurement concept, and its validity and accuracy were discussed. This system was also applied to hybrid simulation tests, and the significant improvement of the proposed measurement system was obtained.