Experimental and numerical study on dynamic responses of three-story building supported by T-BAGS base isolation and vibration control system

T-BAGS is a seismic base isolation and vibration control system. It is composed of two stacked layers of geotextile sandbags filled with sand. A slip sheet is sandwiched between the upper and lower sandbags to control the slippage between them. Slipping between the upper and lower sandbags works as base isolation. Furthermore, the hysteretic shear deformation of each sandbag plays a role in vibration control. In this research, the static and dynamic behaviors of the T-BAGS system are firstly investigated through laboratory tests, including simple shear tests on one sandbag and shaking table tests on six sets of T-BAGS. Then, dynamic numerical analyses of the shaking table tests are conducted. Based on the results, dynamic 3D analyses of a 3-story residential RC building, subjected to a severe earthquake, are conducted with and without the T-BAGS system. The building and the T-BAGS system are integrated and modeled as a three-dimensional series of masses and nonlinear springs. In those numerical analyses, the influence of the rigidity of the sandbags on the dynamic behaviors of the building is investigated. The results indicate that the response acceleration of the building, induced by the severe earthquake, could be considerably attenuated through the use of the T-BAGS base isolation and vibration control system. It is emphasized that the hysteretic shear behavior of the sandbags contributes significantly to vibration control.