The site is huge, covering an area of 16ha. It is currently a hive of activity and awash with an array of construction plant and workers. By 2010, however, the site will have been transformed into the UK’s first purpose-built media city, an internationally significant hub for the nation’s media and creative industries with five BBC departments at its heart.
Media City, located next to the Manchester Ship Canal in Salford, represents the first phase of a redevelopment project which could eventually include much more canalside land, as the developer Peel Holdings has a large portfolio in the area.
The Media City development will include three BBC office blocks, other speculative offices, a hotel, residential blocks, a 2,000 space multi-storey car park, a new dedicated Metro tram link and a large public realm surrounded by shops and restaurants.
The building with the largest footprint – 12,500m2 – and at the centre of the project, is a large steel framed studio building with two conjoined towers, one a 16-storey hotel and the other a 19-storey office development. Steelwork contractor William Hare will, at the end of a 56 week programme, have fabricated, supplied and erected more than 7,000t of structural steel for this large and imposing edifice. The building will house six large production studios and three smaller ones. Three are for the BBC, including one for the BBC Philharmonic Orchestra and three will be for other broadcasters.
The building is around a central corridor which separates the two rows of three studios. The broadcasting studios vary in size, with spans from 24m up to 32m, but they are up to 26m high, which is the full height of the building. Management contractor Bovis Lend Lease says the requirement for large open areas was one of the main reasons steel was chosen for this building. "We looked at all framing possibilities for each individual building and steel was the best option for the studio, not just because of the spans, but also acoustically," says Bovis Lend Lease project director John Hyne.
Structural engineer for the project is Jacobs and project director Stephen Lamb agrees: "The size of the studios meant steel was the only realistic option." As for the two towers, he adds: "They are the same structure as the studio on the bottom three levels, so it made sense to use steel for them as well."
Continuity apart, what also played a major role in the decision to construct the towers in steel was the need to maximise floor to ceiling heights, which led to selection of the Corus Slimdek system, of asymmetric beams (ASBs) and ComFlor 225 deep decking. Meanwhile, to accommodate the large spans and column free areas of the studios, a series of large trusses are being erected at roof level. These sections are all 2.8m deep and brought to site in two pieces. They are then bolted together on the ground and lifted into place.
Studio C – one of the BBC studios – is the largest of the six. It has a total of 18 trusses based on a 7m grid pattern. The depth of the trusses is then used to accommodate the vast array of necessary services. Isolating each individual studio was necessary to stop noise entering or escaping the facility. "Each studio is effectively a semi-independent structure," says Hyne. "They all comprise concrete encased steelwork beams, upon which dense blockwork panels are constructed. All columns are based on acoustic bearings which segregate the studio from the foundations."
The overall structure has five concrete cores, three in the 19-storey office block and two in the hotel tower. These provide the stability for the tower blocks, but the studio area derives its stability from internal bracing. Most of the bracing is housed within the internal walls of the central corridor which acts as the structure’s spine.
The back elevation of the studio building houses a large loading bay, able to accommodate three trucks at any one time. It is located within a large 2.5m cantilevering facade and a large transfer structure, consisting of steel trusses, needed to be installed. Meanwhile, the front elevation of the studio building contains a large open area which could be used as public space and for exhibitions. This area also contains a mezzanine level, which has three smaller studios for general usage. Approximately 2,000t of structural steelwork will be erected for the two towers. Both of these semi-independent structures are centred around concrete cores and each is being constructed with internal spans up to 9m.
Acoustics have also had a significant impact on the use of steelwork in these areas too. The 92m-high office tower has predominantly 406mm x 356mm x 634mm columns, brought to site in approximately 6m lengths. These heavy sections were specified as they best aid the sound insulation requirement for each individual floor. In the 68m-high hotel tower, acoustics were not viewed as such an important issue and so slightly lighter sections – 406mm x 356mm x 287mm columns – have been specified.
Crawler cranes have erected this steelwork and most of the studio steelwork, while tower cranes are handling concrete for the lift cores. "By the time the cores are complete, mobile and the tower cranes will then be used to erect the tower’s steelwork," explains Mr Hyne. "Due to programming, the concrete team were on site first and the cores have to be completed, with cast-in plates to accept the steel beams, before the steel erection on the towers can begin."
Media City UK, Salford Quays, Greater Manchester
Client: Peel Holdings
Architect: Fairhurst Design Group
Structural engineer: Jacobs
Management contractor: Bovis Lend Lease
Steelwork contractor: William Hare
Project value: £415M
Steel tonnage: 7,000t