Cambell Brown Engineers

Selfridges

Selfridges proposed to remodel the existing store at Oxford Street, London. The existing structure was a compilation of existing infill buildings between the classic 1930s structure and a more recent 1960s acquisition. Parts of all these various buildings would be demolished or altered to allow a new structure to be built beneath and adjacent. Cambell Brown Engineers was engaged prior to works commencing to develop a process that would enable the works to proceed while keeping key areas of the store operational and without disturbance. Cambell Brown Engineers provided the crucial design services needed to join the multiple structures together in the temporary condition whilst preventing disruption to store operations.

Client:Selfridges & Scudder Demolition

A key concern for the client was the need to maintain operational status for the stores with minimal disruption to customer experience and store logistics. Cambell Brown Engineers developed a sequence that formed the basis of the Scudders programme to enable this whilst addressing the issue which arose from the delivery of a project in a structure which had undergone significant alterations over its lifetime, with minimal records available. We developed discrete stage modelling to build a methodology for delivering the works to the basement, ground and first floors, whilst enabling continued operations on the retail levels situated higher in the structure. We understood that the lack of accurate plans and information would present significant challenges to any team undertaking works. To address this we modelled all the information that we did know including the extensive (and previously unmapped) utilities, unusual structural compositions and multiple historic alterations. The temporary work design was then based on ‘envelopes’ that could deal with a large variation in build-ups to ensure flexibility. To effectively move the load from the existing columns to the temporary supports and back on to the permanet columns. This the main supporting columns would induce movement and cracking to the occupied upper levels. Our jacking designs allowed pre-load and pre-deflecting of both the temporary structure prior to demolition and the permanent structure afterwards. The building was carefully monitored during all stages of loading and unloading.