The Lancasters is a major re-development of a 180 metre long Grade II-listed building fronting onto the Bayswater Road near Hyde Park, London. The scheme involved retaining the façades of the building and re-developing the interior, as well as constructing a 3 level underground car park which stretched along the entire length of the building between the southern façade and Bayswater Road. The latter required excavation to a depth of around 10 metres below street level. The LUL Central Line tunnels run under Bayswater Road immediately to the south of the site at a depth of around 20 metres below ground level. Hence, movement caused by the excavation works was a critical element of the design.
GCG were appointed to assist with the geotechnical aspects of the project, which included assistance with the design of the underpinning works for the façade retention scheme and advice on solutions for the retaining walls and foundations. Moreover, GCG undertook finite element analyses of the construction processes in order to assist in the design and negotiations with Metronet, who were responsible for the tunnels. During the tendering process, GCG assisted the successful contractor with alternative designs for the temporary works. The groundworks were undertaken using the principles of the observational method, with the limits adopted based on GCG’s work. Measurements taken of the ground and wall movements, as well as movements of the tunnels, were carefully reviewed and were found to compare well with the predicted behaviour.
Grammatikopoulou, A., St John, H. D. & Potts, D. M. (2008). Non-linear and linear models in design of retaining walls. Proceedings of the Institution of Civil Engineers – Geotechnical Engineering, 161 (6), pp.311-323.