The design of a new £160m cancer centre has echoes of the Paris Pompidou but the offsite processes behind it are also speeding up construction and delivering a more efficient building.
Project: New Cancer Centre at Guy’s Hospital
Client: Guy’s & St Thomas’s NHS Foundation Trust
Contract value: £160m
Main contractor: Laing O’Rourke
Architect: Rogers Stirk Harbour + Partners
Structural engineer: Arup
M&E subcontractor: Arup
Start date: May 2013
Completion date: November 2016
London Bridge is currently one of the most logistically challenging locations to deliver a construction project.
Aside from the narrow streets, clogged with the capital’s traffic, there are several major building jobs running concurrently.
These include Network Rail’s Thameslink upgrade at London Bridge station, the ongoing fit-out of the Shard, and a new £160m cancer centre at Guy’s Hospital.
The location has shaped the approach of the project team delivering the new 14-storey Guy’s Hospital Cancer Centre.
Main contractor Laing O’Rourke has used its design for manufacture and assembly processes as widely as possible to reduce in situ building work.
The design philosophy of architect Rogers Stirk Harbour makes maximum use of the space available on a tight footprint (see box).
Roman boat influences foundations
Work began on site in May 2013. The groundworks phase was complex due to the site’s location, with the piling running to a range of depths – the deepest going down 42 m.
“The job is challenging logistically, there are no storage areas”
Guto Jones, Laing O’Rourke
The remains of a Roman boat also complicated matters. The basement structure was constructed around the boat and includes a 2.5 m-thick concrete transfer slab.
It will protect the boat and allow it to be removed if necessary at a future date.
Much of the superstructure and many of the main building services elements are now complete. But managing the project on this tight, triangular-shaped site has not been straightforward.
Laing O’Rourke project leader Guto Jones says: “The job is challenging logistically,” he says. “There are no storage areas.
“We have two very small holding areas, one that can hold two articulated lorries a quarter of a mile from the site, and one other articulated space we share with Network Rail at London Bridge station. When trucks arrive at the site, we can only offload from two at a time.”
Juggling site deliveries
Deliveries are managed using Laing O’Rourke’s ‘Juggler’ system. This web-based scheduling program helps coordinate the arrivals of materials and equipment on site, allocating different slots to suppliers depending on priority.
Subcontractors receive a time digitally to let them know when to arrive at the site. It prevents a fleet of trucks arriving at the same time and cuts congestion around the hospital.
Mr Jones meets with all package managers daily to plan the schedule, on top of the weekly ‘look-ahead’ meeting.
“Sometimes it’s a last minute call to say whether a supplier can deliver or not. That shows how the lack of storage affects logistics planning”
Guto Jones, Laing O’Rourke
“We check if the materials can be accommodated, and sometimes when they can’t, lorries have to be delayed,” he explains. “There is a hierarchy of priority for the different packages. Obviously the concrete frame was top when we were constructing that.
“But the Juggler system is flexible enough to allow you to move around delivery times if necessary.”
The worst disruption to deliveries has been caused by wind.
“We lost a day and a half a week on average for a couple of months either side of Christmas 2014,” Mr Jones says. “So sometimes it’s a last minute call to say whether a supplier can deliver or not.
“That shows how the lack of storage affects logistics planning.”
With so many other projects on site around London Bridge, a Bankside constructors group has been set up so that different contractors can meet to keep each other abreast of what is planned.
“It has not caused us to change anything,” Mr Jones says.
“But means we can be aware when another contractor may need to shut off a road, for example, and then we can make contingency plans.
The group meetings also enabled us to secure the shared storage space with Network Rail.”
DfMA time saving
The tricky logistics illustrate why the DfMA approach was chosen for the Guy’s Cancer Centre.
It will allow the project to be built 30 per cent more quickly than using conventional building methods, Laing O’Rourke estimates.
Much of the pre-assembly work is being done at the firm’s Explore Manufacturing plant in Worksop, Derbyshire, including 3,756 concrete elements which make up the building’s frame and 1,080 unitised cladding panels that will be fixed to the external faces.
Any insitu elements from the original design have been moved into the factory wherever possible. In the basement, 80 per cent of the blockwork walls were re-specified as precast slabs.
Externally, one striking architectural feature is the concrete shear wall on the southern elevation. It was actually built from five precast elements, each weighing 11 tonnes, with grouting between them the only in situ work required.
“The five panels were brought to site on a delivery truck using a holding structure resembling a ‘toast rack’ to keep them upright,” Mr Jones explains.
The offsite approach has allowed construction of the centre’s 14 floors to proceed rapidly. Apart from the first level, which is a concrete slab, the others have each been built in four days (excluding fit-out), which includes steel sections and columns, ‘smart walls’ (which include service runs), air-handing plant, plus other prefabricated service modules.
BIM has been used to make the installation process as efficient as possible, avoiding clashes between different packages.
New structural flooring system
On the roof level, Laing O’Rourke is trialling a new structural flooring system, called E6, also manufactured at the Explore factory. It is a composite, comprising a primary concrete slab plus a secondary lattice slab which acts as permanent shutter.
The slabs are supported with temporary steel brackets, allowing the floor to be installed without temporary propping, and then joined together using bespoke jointing couplers. The joints develop the full strength of the slab reinforcement so that the completed structure behaves similarly to a floor cast insitu. Laing O’Rourke has patented the whole system.
“The advantage of E6 is it takes away the need for propping, which means we can get onto floor plates much earlier,” Mr Jones explains. “We trialled it on the Leadenhall Building, and now here. We don’t expect significant programme savings here, but we will when it is rolled out elsewhere.
“In future, the elimination of temporary propping could allow bathroom pods, smart walls and other follow-on trades to be preloaded onto the floor plate to allow fit-out and handover to proceed rapidly in parallel with the frame construction.”
Problem becomes opportunity
The services have also been extensively prefabricated.
The most innovative element is the 12-storey modularised steel plant tower, constructed in under eight weeks. It has been designed in five sections, each one 4.2 m high.
The plant tower houses an air handling unit on each level, which services the corresponding floor, and duct work is distributed along the outside via walkways which also act as a support and provide maintenance access.
“We would normally have opted for plant rooms or put the plant on the roof,” Mr Jones says.
“However, because of the constraints of the site, we decided on the tower instead. But this has other advantages. Because the plant tower feeds air conditioning and other services directly to each floor, less ductwork is needed internally – an important consideration given the spatial constraints on the project. So a problem has become an opportunity.”
Some of the heavy duty clinical equipment areas needed to be built insitu, such as the six radiotherapy bunkers, which weigh 5,000 tonnes each. “We’ve had to design for the worst case scenario; because the technology moves so quickly, the trust was unable to make a decision on all its clinical equipment when we started designing the project,” Mr Jones explains.
The project is now roughly two-thirds complete, with the fit-out work to follow. The completed cancer centre is due to open in autumn 2016.
Echoing Pompidou and Lloyd’s
The design for the new cancer centre at Guy’s Hospital was selected following a RIBA competition in 2011.
Rogers Stirk Harbour teamed up with Laing O’Rourke and Arup.
“The trust wanted quality of design but also cost and programme certainty, which is why they wanted contractor-led teams,” says Ivan Harbour, partner at the architectural practice.
The 14-storey building is being arranged into three ‘care villages’ - chemotherapy, radiotherapy, and outpatients - each arranged on top of the other. They will be entered via a ‘village square’, with accommodation arranged on two or three sub-floors, and will include landscaped balcony gardens.
Rogers Stirk Harbour worked with Laing O’Rourke on the Leadenhall Building, but has an association that dates back much further.
“We’ve worked with Ray O’Rourke since 1987,” Mr Harbour says. “He is an extraordinarily single-minded man. Back then, he introduced construction methodology into the design process, which influenced the design of the building.
“This holistic approach has always resulted in a far better outcome, with architect, engineer and constructor working together from the outset.
“This is why off-site manufacturing is used so widely on O’Rourke projects, though it is just one strand of his philosophy.”
Two of the best known projects of Rogers Stirk Harbour are the Pompidou Centre in Paris and London’s Lloyd’s Building.
The new Guy’s Cancer Centre will have an echo of these with external services running out of the modular plant tower through external ductwork.
“We brought the ductwork outside the building to boost the internal space; it would have added 2 ft in height to each floor, and the trust was keen to maximise the floor heights,” Mr Harbour says.
“And because it’s coming straight from the plant tower, we have reduced complexity of ductwork. It also makes the constructor’s job easier.”
BIM Level 2 was used “from day one” on the project, Mr Harbour says.
“It is central to Laing O’Rourke’s DfMA process, but has also been useful for the client, who can ‘walk through’ a digital design of the building,” he says.
“The clinical design gives a useful visualisation to users, and they have been able to change any fixtures and fittings where necessary.
“It will also provide a source of information for the hospital’s facilities management.”