| Abstract: | This paper presents a new geosynthetics isolator composed of stacked sandbags for buildings’ base-isolation method to improve human comfort under subway-induced environmental vibrations. The static and dynamic mechanical properties of the isolator are tested in a laboratory first. Then field experiments are performed with a full-scale building to investigate the effectiveness of the isolator. The results indicated that the bearing capacity is mainly influenced by the soft contact interfaces between different sandbags, and is sufficient for most low-rise and mid-rise buildings. Similar to some springs in a series, the soft contact interfaces make the vertical stiffness of the isolator low enough to isolate vibrations. The friction forces between sand particles are a benefit to dissipating energy, which increases the damping ratio to 14%. After the installation of geosynthetics isolators, the vertical vibration and secondary air-borne noise inside the building are effectively suppressed, and therefore the comfort for residents is enhanced. Further, there is no negative impact caused by automobile vibrations on the isolated building because the damping ratio of the isolator is high enough to resist resonant amplitudes. These results demonstrate that the isolator is feasible for buildings near subway transportation. |
