Driven pile foundation reuse in East London, UK

Abstract

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