22 STATION ROAD – OFFICE BLOCK DEVELOPMENT, CAMBRIDGE
The construction of a multi-million pound office development by Wates Construction in Cambridge Brookgate’s 22 Station Road scheme, a £33m five-storey development of 64,770 sq ft office space. Upon completion, the development will become home to engineering consultants Mott Macdonald and Birketts Solicitors.
The site is underlain by Quaternary river terrace deposits overlying solid deposits of the West Melbury marly chalk formation of the grey chalk subgroup. This is underlain by the Gault Formation. The Cambridge Greensand, which is sometimes present between these two formations, may be present in very narrow bands at this site. Made ground is present above these natural strata.
The design was carried out in accordance with Eurocode 7 Code of practice for foundations.
The design specification called for the structural piles will form part of the renewable energy strategy of the building and are required to act as Energy Piles. To this end each pile contains circulation pipework for a ground source heat pump (GSHP) to be designed by a specialist.
Polyethylene pipework was secured by cable ties to our 1H32mm x piles lengths up to 25m in 450mm and 600mm CFA piles. Once bores are drilled to design depth and concrete injected reinforcement together with the secured pipe work was lifted by a service crawler crane and plunged carefully into the wet concreted CFA pile.
The ground source heat pump specialist was in attendance during the preparation of the ground heat exchanger pipework loops for the insertion into the wet concrete piles and they carried out their pressure testing all primary GSHP energy pile pipe-work between the heat pumps and ground loop heat exchangers once connected.
Working pile load tests using anchor pile method were carried out in accordance with ICE and project specific piling adopting a reduced factor of safety based on EC7 codes of practice plus 100% sonic integrity testing on all piles.