抄録
The rubber bearings to be used for an isolation floor which is effective not only for strong earthquakes but also for weak earthquakes and even ambient micro-vibration, must be able to provide the rated masses of 1 5003 000 kg per bearing with horizontal stiffnesses corresponding to natural frequencies of 0.40.5 Hz and to undergo a horizontal displacement of 20 cm or so. Such performance cannot be achieved by rubber bearings of normal structure because the rated masses are too small. As a solution to this problem, multi-stage rubber bearings were developed, which consisted of 8 stages (each stage comprising 4 rubber bearing elements) piled up with 7 stabilizing plates between the stages. Through static and dynamic tests, it was confirmed that the multi-stage rubber bearings satisfied the requirements and were effective even for micro-vibration.
