Influence of Excess Pore-pressure on the Seismic Response of Single and Closely Adjacent Structures on Saturated Sand

This study was initiated following recognition that most structures exist, not in isolation, but in a setting where there is sharing of the common supporting foundation soil. Generally, structures exist in clusters, particularly in CBDs, with varying degrees of interaction. In truth, engineers deal with "systems", where no structure exists in isolation. However, experimental evidence of the seismic response of multiple structures, particularly on saturated sand, is scarce since most studies are numerical and focus on stand-alone structures. The present study helps bridge this paucity of experimental work by developing an understanding of the seismic response of closely adjacent structures on saturated loose sand. A variety of configurations of single degree-of-freedom structures, with different fixed-base fundamental frequencies, were studied using a large laminar sand-filled box on a shake table. Recorded ground motions from the Canterbury earthquake sequence were used. The free-field and the stand-alone case for dry and saturated sand were studied as references. Differences between the response of stand-alone structures on saturated and dry sand are discussed. The response of a structure of focus, standing adjacent to neighbouring structures, on saturated sand is compared to that of the stand-alone case. In general, structures in a cluster experienced an attenuated response.