Seismic base isolation using a layer of natural stone pebbles

Abstract

The results of a shake table study of the effectiveness of seismic base isolation using a layer of natural stone pebbles are presented. Models of stiff and medium-stiff buildings were tested. Case studies were conducted with the model foundation on the rigid base and four different layers of pebbles (thin and thick layer with small and large pebbles). Four different horizontal accelerograms were applied. The characteristic displacements, accelerations and strains were measured. Strains/stresses of the tested models were in the elastic area. It was concluded that the efficiency of the stone pebbles layer under the foundation, compared to the classical solution of a foundation, strongly depends on the type of the applied excitation and depends relatively little on the layer thickness and pebbles fraction. The solution proved to be very efficient, with a reduction of earthquake forces up to about 70%.