Feasibility study of vibration reduction device for vertical direction

Abstract

Earthquakes frequently occur in Japan so far. Therefore, seismic isolator is attracting attention to protect buildings. In order to reduce all direction of shakings, three-dimensional (3D) seismic isolator is needed. 3D seismic isolator is composed of isolator for horizontal direction and vertical direction. Because 3D seismic isolator can effectively reduce all shaking, it can protect people and objects in the building. If 3D seismic isolator is established, we will be closer to achieving sustainable society. However, there are not many studies on seismic isolation for vertical direction. In this study, to develop an effective vibration reduction device for vertical direction. A vibration reduction device using a nonlinear spring was invented in the past. According to experiment, devices with this mechanism were reducing vertical vibration. Analysis model is based on the device. To reduce vibration more effectively, analysis was conducted with different parameters such as spring constant or range of motion for vertical direction. Then, the differences in behavior and the effect of seismic isolation are examined from resonance curves obtained from analysis results. In addition, the experimental and analytical results will be compared to investigate the conditions necessary to improve the seismic isolation effect.