Interaction of Closely Spaced Shallow Foundations on Sands and Clays: A review

The evaluation of the static interaction of closely spaced footings and its influence in the overall bearing capacity and settlement on sand and clay soils is addressed in this review. The work is accomplished through a comprehensive look into all relevant literature regarding the interaction of sallow foundations, assessments are made, and conclusions are drawn which will ultimately be relevant to future endeavors associated with the design and the evaluation of closely spaced shallow foundations in terms of determining the optimal spacing between footings, enhancing bearing capacity, and controlling deformation. Furthermore, the work is divided to three major approaches: theoretical studies, experimental or field tests, and numerical analysis. Each have been discussed thoroughly in details, with indicating the shortcomings of previous studies and where each approach has reached. The result of this review has showed that nearly all previous research studies explored the effect of the interaction of closely spaced shallow foundations on the bearing capacity at the ultimate failure compared to the settlement behavior which is for some reason not addressed profoundly,even though it is more critical than bearing capacity. Additionally, current regulations and codes have not devoted a major effort toward addressing the influence of closely spaced shallow foundations appropriately, especially today,where the limitation of a site and the placing of footings close together in order to accommodate structural details are becoming a more common issue.