This major development lies directly above LUL’s Victoria Line Station at Vauxhall, involving residential and business space and at one time potentially the Mayor of London’s offices. This involved the construction of a number of 2.4m diameter piles up to 65m deep, within 2.5m of an escalator shaft, together with the construction of pile caps up to 5m deep.
For the early phases of the St George’s Wharf development GCG advised the developer on the potential effects of the development on LUL’s tunnels and installations, particularly the escalators, and devised foundation systems that would minimise these effects. From this work GCG initiated a programme of research into pile-tunnel interaction problems at Imperial College, receiving an award from the institution of Civil Engineers to partially fund this work.
On the basis of GCG’s analysis, which included temporary works schemes, methods of construction and sequencing were prescribed and an instrumentation system devised to monitor the behaviour of LUL’s assets throughout construction.
Following completion of the earlier phases of the St Georges Wharf development at Vauxhall GCG were retained to advice on the construction of the foundation system for the tower. During construction of the piled foundations there was a requirement to modify the method of constructing the piles and the design of the foundation system as a whole. GCG were retained to provide advice on the investigations required to define a revised method of construction for the large diameter piles and to provide advice on construction issues as they arose. Subsequently GCG were retained by the structural engineer to provide advice on the design of the Tower in relation to dynamic effects resulting from wind loading. This necessitated assessments of different loading conditions in order to develop the structural design using advanced numerical methods to model the foundation system.