Abstract:
Soil-structure interaction (SSI) has been widely studied during the last decades. The
influence of the properties of the ground motion, the structure and the soil have been
addressed. However, most of the studies in this field consider a stand-alone structure. This
assumption is rarely justifiable in dense urban areas where structures are built close to one
another. The dynamic interaction between adjacent structures has been studied since the
early 1970s, mainly using numerical and analytical models. Even though the early works in
this field have significantly contributed to understanding this problem, they commonly
consider important simplifications such as assuming a linear behaviour of the structure and
the soil. Some experimental works addressing adjacent structures have recently been
conducted using geotechnical centrifuges and 1g shake tables. However, further research is
needed to enhance the understanding of this complex phenomenon.
A particular case of SSI is that of structures founded in fine loose saturated sandy soil. An
iconic example was the devastating effects of liquefaction in Christchurch, New Zealand,
during the Canterbury earthquake in 2011. In the case of adjacent structures on liquefiable
soil, the experimental evidence is even scarcer.
The present work addresses the dynamic interaction between adjacent structures by
performing multiple experimental studies. The work starts with two-adjacent structures on
a small soil container to expose the basics of the problem. Later, results from tests
considering a more significant number of structures on a big laminar box filled with sand
are presented. Finally, the response of adjacent structures on saturated sandy soil is
addressed using a geotechnical centrifuge and a large 1g shake table.
This research shows that the acceleration, lateral displacement, foundation rocking,
damping ratio, and fundamental frequency of the structure of focus are considerably
affected by the presence of neighbouring buildings. In general, adjacent buildings reduced
the dynamic response of the structure of focus on dry sand. However, the acceleration was
amplified when the structures had a similar fundamental frequency. In the case of
structures on saturated sand, the presence of adjacent structures reduced the liquefaction
potential. Neighbouring structures on saturated sand also presented larger rotation of the
footing and lateral displacement of the top mass than that of the stand-alone case.