When developers Hammerson UK received permission to extend and renovate the WestQuay Shopping Centre in Southampton, they sought our expertise in complex cantilevers and our proven portfolio in leisure and retail structures to inform their designs.
We worked alongside architects ACME to provide structural designs for Phase 1 of the development, which comprised the construction of a six-storey structure with retail units on the lower levels and restaurant and leisure facilities above, all set within a concrete frame. In addition, a multi-screen cinema is situated on the upper levels, accessible via a grand staircase in the south-west corner of the centre. A link bridge over Harbour Parade will also provide access to an existing car park.
Subterranean restraints required a delicate approach to the foundation design; existing foundations were likely to cause obstructions, whilst a Grade I-listed medieval town wall required ongoing archaeological monitoring, and services and utilities run throughout the site. An existing culvert also enters the boundary, which has a strict approval procedure that will dictate any works adjacent to it.
The cinema needed to occupy a larger space than the units below, with a number of column-free spaces in the foyer and auditoria; we proposed a cantilever which extended up to 25 m beyond the building envelope directly below. It was paramount, given the strain that this would place on supporting structural elements, that we make the structure of the top storeys as lightweight as possible, so we therefore proposed a steel frame solution.
Wherever possible, we ensured that the cinema grid aligned with the 10 × 10 m retail grid below, with local variations to align with the cinema layout. For the roof we reviewed two options involving standard beams and cellular beams. The latter solution is considered preferable in terms of structural depth and ease of service runs, but will require careful coordination.
Extension and introduction of leisure facilities at this Southampton shopping centre
£ 48 million