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 new development, unlocking a site that had been derelict for many years since the demolition of the former Pirelli factory. The new build, mixed-use scheme 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. A 10-screen cinema is situated on the upper levels, accessible via a grand staircase in the south-west corner, and a link bridge over Harbour Parade provides 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 entered the boundary, which had a strict approval procedure that dictated works adjacent to it.
The protected sightline from the historic town wall and the requirement of a new public realm limited the massing at the lower levels to the south of the building. In order to accommodate the client’s required floor area for the cinema in the upper levels, a lightweight steel frame that cantilevers out of the structure was developed, which not only achieves the floor area necessary, but also maintains the clear views of the town walls. This steelwork was also able to achieve the long spans required for the large, uninterrupted auditoria spaces. Below, the concrete frame of the lower levels is set back, only stepping out at the lowest levels to provide restaurant terraces and footpaths.
The cinema overhangs the base of the building on three sides, cantilevering around the whole perimeter, peaking at an impressive 28 m from the nearest vertical supports. Finding an efficient mechanism to deliver a structural system that supports such huge cantilevers relied on close coordination and space planning between ACME, AKT II and cinema operator National Amusements, as well as particularly clever engineering.
An impressive cantilever system helps introduce new leisure facilities at this Southampton shopping centre
£ 48 million
2017 AJ Architecture Awards – Leisure Project of the Year