Experimental study on foundation isolation using geosynthetics

Abstract

In the last decades, alternative low cost seismic isolation techniques which are commonly known as Geotechnical Seismic Isolation (GSI) systems were developed to mitigate earthquake hazards. These are known as Rubber Soil Mixtures (RSM) and Geosynthetics. Soil isolation and foundation isolation are the types of GSI with geosynthetics which can easily be applicable for low-to-mid rise buildings. The aim of this study is to determine the effects of foundation isolation with geosynthetics on seismic performance of low-to-mid rise buildings by using shaking table experiments. The proposed GSI system is comprised of a geotextile overlying geomembrane placed underneath the foundation with three different configurations. More importantly, this study is the first study on foundation isolation with geosynthetics considering different configurations by using shaking table under seismic loadings. Two different shaking table models representing the fixed based and isolated based buildings were designed as a 1:10 scaled building models. The effects of foundation isolation in terms of the number of the story of the building, type of geosynthetic couples, GSI configuration and dynamic motion characteristics on the seismic performance of the model buildings were evaluated. The comparative results of the fixed based and isolated based building models revealed that the proposed GSI systems can substantially reduce the horizontal accelerations, horizontal story drifts, Arias intensity, base shear, and base moment of the buildings under different seismic motions. The proposed method in this study can be a good alternative method to mitigate earthquake hazards for developing countries.