Driven pile foundation reuse in East London

Multiple phases of redevelopment of the London Docklands have resulted in the need to replace existing structures with new, often larger, structures. This paper presents the case history of a 1980’s low rise office building (3-4 stories) being replaced by a medium rise (5 stories + roof terrace) recreational building structure. The 1980’s building was founded on driven close-ended steel tube piles located within one of London’s historic docks. Subsequent to the 1980’s building construction, London Underground tunnels were constructed below the dock in the late 1990’s in close proximity to the structure. Piling in the dock adjacent to the LU tunnels results in restrictions to pile construction methodology. The new structure reused the driven piles in the dock and added new onshore bored piles to accommodate a larger building footprint landward. The pile reuse justification used the original preliminary pile load test and driving records along with current design codes. The 1980’s allowable working loads stated on the design drawing were less than that required to support the new building thereby requiring re-interpretation of preliminary pile load test results. The pile reuse assessment justified an increase in pile working load from 1050 kN to 1760 kN.