Page 4 - Deep Basements Project Examples

Godalming London Exeter
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Harrogate Bristol Dublin
01423 276000 0117 373 6140 (01) 554 6210

Deep Basements - Example Projects

Seymour Street, continued CGL developed a strategy to re-support the demolition
CGL has provided considerable value engineering by towers, with a very fine tolerance for movement, so that
rethinking original proposals, for example by changing the RC grillage and mini piles could be removed and the
from an underpinned design into a pile design which saved main construction could take place.
months on the construction programme and reduced risks.
CGL also provided the primary temporary works designs

In another example 5000m3 of construction waste was for walers and props to support the perimeter retaining
originally planned to be retained onsite to provide ballast wall during construction for minimal obstruction to piling
against heave induced uplift. CGL's ground movement whilst maximising working space on site.
analysis concluded this was not necessary to achieve
sufficient stability so it was removed, significantly CGL used geotechnical and geostructural design software
increasing the usable volume of the basement. including:

The constrained site presented an additional challenge as Ÿ WALLAP to analyse the retaining walls and
the towers erected during demolition to support underpins in the lateral condition.
neighbouring party walls were on a mini pile concrete Ÿ PLAXIS 3D to model the forces in the perimeter
support grillage that clashed with the position of a transfer support props and reaction caps, the support piles
structure required by the final construction design. for the tower cranes and impact on the adjacent
Furthermore, 3m deep attenuation tanks were required to Royal Mail tunnel.
be located under the 10m deep basement and less than a Ÿ CADS A3D frame analysis to inform the RC capping
metre from the tower bases. beam and steel walling design.

Re-supporting the towers erected during demolition

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