A Novel Three-Dimensional Isolation Bearing for Buildings Subject to Metro- and Earthquake-Induced Vibrations: Laboratory Test and Application

The implementation of three-dimensional (3D) isolation technology effectively enhances the structural seismic resilience and mitigates the impact of vibrations induced by metro trains. However, the challenge remains to increase the vertical loading capacity of 3D isolation bearings while reducing their vertical stiffness and guaranteeing excellent stability. The 3D isolation bearing (3DIB) consisting of an improved laminated natural rubber bearing (LNR-400-imp) and spring bearings (SBs) built vertically in series were proposed in this study. Its design principle and working mechanism were introduced, and prototype specimens were designed and manufactured. The 3D mechanical performance of the 3DIB was investigated through horizontal and vertical tests. Furthermore, the earthquake and metro vibration isolation performances of the building installed with the 3DIB were analyzed using a case study. The results demonstrated that the 3DIB exhibited horizontal energy dissipation effect, and had stable vertical performance, higher vertical loading capacity, and lower vertical stiffness attributing to the improved LNR-400-imp and SBs. Specifically, the vertical stiffness of the 3DIB was about 1/14 of that of the traditional LNR-400-tra. The case study demonstrated that the 3DIB had remarkable earthquake and metro vibration isolation effects, behaving huge potentials in enhancing the seismic resilience of structures and mitigating the impact of metro vibrations. This study offers valuable insight and practical guidance for future research on 3DIB in the field of vibration isolation, contributing to the advancement of 3D isolation technology.