In situ tests of building structures isolated by innovative three‐dimensional vibration isolation bearings

Abstract An innovative three‐dimensional vibration isolation bearing (3D‐VIB) was proposed in past studies to mitigate rail‐induced vibration and improve the seismic performance of buildings. The 3D‐VIB was composed of a thick laminated rubber bearing as the vertical vibration isolation element and a friction pendulum system as the horizontal seismic isolation element. In this study, in situ tests were carried out on a subway over‐track structure with 3D‐VIBs. The in situ tests included the subway‐induced vibration excitation test and the horizontal loading test on the same structure. In the subway‐induced vibration excitation test, the vertical isolation performance of the test structure was changed by transforming the isolation layer from a normal vibration‐isolation‐state to a non‐isolation‐state. The comparison between the two states proved that the installation of 3D‐VIBs significantly changed the vertical vibration mode and reduced the subway‐induced vibration of the superstructure. The shear performances of the isolated structure were examined by the horizontal loading test, which subjected the superstructure to a large horizontal movement under external load. The shear performances of the structure with 3D‐VIBs were consistent with that of the 3D‐VIB specimens measured in the laboratory. The in situ tests confirmed the effectiveness and stability of the 3D‐VIBs when applied to practical engineering.