With time tight to complete a 90 000 m2 hq the construction team moved onsite. Alison Luke visits GSK House to find how the task was completed.
he task: to complete 93 000 m2 of state-of-the-art offices in 31 months on budget and to planning regulations. This was the target facing those involved in the construction of GlaxoSmithKline's new UK headquarters. The solution? Move the entire construction team onsite, promote close working and co-ordination, and add a dose of innovative thinking.

The £300 million GSK House is sited in Brentford, west London and will soon be home to 3000 office-based staff. The building has taken shape on a 13·4 acre brownfield site adjacent to the M4 and almost midway between the company's two existing London offices. It comprises four main office blocks – three five-storey buildings and a 13-storey tower. The tower sits central to the lower buildings, two of which curve either side producing a view from above that resembles a boat on the crest of a wave.

The buildings are linked structurally but, to ensure flexibility of use and the potential for leasing to other companies, the services are designed to enable split operation. The tower and one curved building will operate as a single unit; the two buildings to the other side of the tower can be operated independently.

An internal street joins the second curved building and its adjacent straight partner. "The street," explains Ken Felton, electrical associate with m&e services consultant WSP, "is like an atrium from ground to fifth floor. Everything is linked at ground level, but there are also intermediate bridges at height across the street." This street "gives the feeling of space" and provides a secure area for circulation and staff facilities such as restaurants.

Ship-shape services
WSP was responsible for both the shell and core and fit-out m&e services, having won the latter contract around nine months after the project began. The building's curves created some initial problems as they made it difficult to get a standard ceiling tile, reported Felton.

The mechanical services for the project are uncomplicated, with air conditioning being supplied by a vav system and some prefabricated plantrooms used. This is a result of the client's desire to use proven technology in this area.

A somewhat different approach was taken for the electrical services. As Felton explains: "One of the biggest problems in the electrical brief was that we needed 10 MW of power for the building." A new 60 MW substation was constructed close to the site to cope with the demand. This cost £3 million, of which, GSK has contributed £1.5 million.

The design of the services has changed little during the project's progress and the buildings each follow the same basic principles. On the electrical side there is a substation in each building, with cast resin transformers. From here power is supplied via rising busbars to distribution boards on each floor. An underfloor busbar system on a 3 m grid supplies electricity throughout the floors. This was chosen to ensure flexibility for future changes of office use or layouts. Flexible desk connections simply plug into this via a specially designed floorplate and distribution system.

A modular wiring system was used for the lighting. This was to cater for the short installation time available: "We needed something that could fit into the programme," stated Felton. Also, with 35 000 luminaires installed throughout, modular wiring provided the flexibility needed. The system provides 10 W/m2 – the result of a client specification and WSP's energy efficiency policy.

Space was a prime consideration in the selection and installation of plant. "The services are fairly well compacted to give the best net-to-gross space possible," states Felton. "We basically had to hit 85% net-to-gross, which doesn't give us an awful lot of space for plant."

All plant is contained at basement or roof level, and the entire roof of the structure is basically one enormous plantroom. But the engineers couldn't alleviate their space issues by simply building skywards – strict planning regulations meant that plant could only rise four metres above the roof line.

With tight spaces came a need for close co-ordination, and WSP was onhand with a simple yet effective solution to the potential installation problems. The company used 3D modelling to design and check plant layouts, but the real co-ordination winner was the cable trays. Felton explains: "For the lv services we came up with a system of using different coloured trays for each service." The simplicity of this system worked well on site, especially as each service had been tendered as separate packages and there were several companies working alongside each other.

  "By putting in different coloured trays each contractor knew which they were meant to use, and this avoided possible conflict problems," stated Felton. "It also helps for future maintenance," he adds. The quantities of tray needed for the project meant that it was possible to have it specially manufactured.

On-site working
Close working within the construction team was highly evident on the project. The first buildings to greet visitors to the site are the temporary portakabins, which form a structure larger than many people's permanent offices and house all members of the team. These have been in place since the project came to site.

"The client wanted the whole team together," explained Felton. The design team resides on the top floor of this fully air-conditioned office space, while the contractors are based in the floor below. This close working was vital to the success of the scheme. Felton states: "As it was such a vast project we needed to sit together and make decisions. It wouldn't have worked if we hadn't all sat together. We didn't have the time to go through the normal weekly meetings process, decisions had to be made fast and here we had the whole team working together."

Workshops run by the design team and main contractor Mace were held daily. Nobody was excluded from these meetings, reports Felton, and they made it easy to make changes if needed.

While selection of contractors was done via a tendering process rather than partnering, with four or five companies bidding for each of the services packages, the design team members were given the opportunity to discuss the quality of those selected for the project.

The use of a drawing management package also helped with the project co-ordination. "All drawings were put on the same system and are accessible via pcs without the need for AutoCAD," states Felton.

Drawings created by the design team on AutoCAD were put onto the system, TDM, as they were issued. When a contractor supplied a drawing it was added to the system and reviewed by the appropriate team in electronic format. This meant that any comments made could be highlighted and saved and there could be no chance of future confusion.

The latest drawings are easily accessible on the system, but any older drawings, with amendments, can also be found. This has removed much of the paperwork associated with large projects but has also ensured that every team member has been kept up to date with progress and has provided the client with a convenient method for storing all data related to the buildings, including the maintenance and operating manuals.

GSK staff have begun to move into the buildings, with the final handover due at the end of September this year. As well as achieving the construction aims, the team's efforts have created a pleasant working environment. Within the offices there is a feeling of space, created in part by the amount of daylight entering from both the internal street and clad exterior. And if workers want real fresh air, laptop plug-in points on the outside parasols allow this. A task completed.

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