Pile Capacity Testing for Reusing the Existing Foundation

Reusing existing foundations is both a sustainable and cost-effective practice. This approach significantly reduces the carbon footprint and the use of raw materials. But to incorporate existing foundations into new projects it is essential to know their bearing capacity along with the dimensions, structural integrity, and remaining life time of that existing foundation. This paper presents an innovative method whereby an existing foundation, built around 1970, was successfully reused, even though the available information was limited. The original as-built drawings indicated the use of precast piles with enlarged bases, but the exact dimensions were uncertain. To determine the pile’s capacity, rapid load tests were conducted on new precast concrete trial piles with (presumably) the same dimensions and driven into the same sand layer close to the existing piles. Instead of testing the existing piles, these trial piles were load tested. This paper details the execution of these tests and how the results provided valuable insights into the calculated pile bearing capacity and pile-settlement behaviour, enabling the successful reuse of the foundation.