In Birmingham Galliford Try is transforming what was once the centre of Britain’s car industry into a new retirement village.
Project: Longbridge Retirement Village
Client: Extra Care Charitable Trust
Contract value: £35m
Contract type: JCT Design and build
Region: West Midlands
Main contractor: Galliford Try
Start date: February 2015
Completion date: July 2017
Birmingham is a city that has a long automotive history.
For years car manufacturing formed the bread and butter for generations of Brummies while the city’s post-war town planners decided the car should dictate their vision of Birmingham’s future.
Castle Bromwich, Washwood Heath, Ward End and Solihull are all areas that have been dependent on the automotive sector, but it is perhaps the suburb of Longbridge that has been worst hit by the collapse of the industry in the UK.
Its huge car plant once kept thousands busy churning out machines for Austin, British Leyland, Austin Rover and Rover Group. The plant, divided by the main A38 Bristol Road, even had its own bridge to carry car shells for the Mini Metro from one side of the plant to the other.
Since the demise of the automotive industry and closure of the car plant, the site has undergone a programme of reclamation aimed at creating a new Longbridge urban centre.
In addition to new homes, shops, colleges and community facilities, part of the plan is the creation of an over-55s retirement village, which is being undertaken by main contractor Galliford Try for its client Extra Care Charitable Trust.
“There will be 260 one and two-bedroom apartments plus communal facilities including gym, bar, restaurant, shops and a communal hall,” explains Galliford Try project manager Ryan Woolley. “The client is keen that the completed complex really will offer everything for its residents.”
This is the latest scheme Galliford Try has carried out for Extra Care, having delivered seven similar projects across the Midlands. It was tendered through a competitive process, with the team getting the nod for the £35m design-and-build contract in early 2015.
Despite the land being an extensively remediated brownfield site, the Galliford Try team carried out a thorough site investigation to ascertain exactly what lay beneath the surface.
“Extra Care is determined the scheme doesn’t have that ‘care home’ feel. We are trying to show that high-end retirement communities are achievable”
Ryan Woolley, Galliford Try
“There was a network of tunnels from the sites MG Rover days but no mention of exactly where they were,” says Galliford Try design co-ordinator Natalie Armstrong. “We needed to be sure what we were dealing with.”
As well as the tunnels, there was also the location of a Second World War command bunker to pinpoint (see box) and a difficult sloping site to work around.
“We started on site in February 2015 with the muck-shift work,” Mr Woolley explains. “There is quite a fall between the east and west ends of the site and so effectively it is split into two with a contiguous piled retaining wall running across the scheme.”
Wartime command bunker attracts attention
At the outbreak of the Second World War, the Longbridge plant changed tack from the manufacture of cars and parts to the production of weapons and tanks.
This important role in the war effort made the factory both an attractive place to table high-powered meetings and also a target for German bombers.
The 16 m-deep reinforced concrete Trentham Command Bunker was built to accommodate these meetings safely. Although the bunker was partially demolished and backfilled when the site was remediated in the early 2000s, the Galliford Try team remained concerned about its location and the possibility of differential settlement around it.
“It is very close to the location of the contiguous pile wall, and although the bunker had been excavated and backfilled previously, this is a deep excavation in an isolated location within otherwise dense sandstone,” Ms Armstrong points out. “There was real potential for settlement.”
The solution was to use the contiguous pile wall and cast a 10 m x 10 m x 995 mm reinforced concrete transfer slab from the 775 mm x 600 mm ground beam running along it. The transfer slab spans the bunker and onto the denser sands away from the backfill around it, providing a safe, solid base without fear of differential settlement.
In all, almost 10,000 cu m of ground was moved offsite under the muck-away contract, with the contiguous piled wall being installed by specialist contractor Green Piling using 450 mm-diameter CFA piles at depths to 25 m.
The team used an array of 150 mm and 250 mm-diameter steel piles, driven to refusal, beneath the building itself. These recycled oil rig pipes were installed across the footprint, the bulk in clusters of three with a pile cap.
Galliford Try Longbridge 4
“The [ground] had been remediated but there was lots of deep fill that was very soft sandy clay,” Ms Armstrong says. “The underlying sandstone is very dense and is at varying levels across the site. Even some of the investigation boreholes were taken to refusal.”
Haul of frames
The development itself is split into a series of linked buildings around a central courtyard. These include two reinforced concrete frame five-storey sections, a three-storey traditional build wing, and two other four-storey sections featuring steel frames. There are also lightweight metal-framed system penthouses on some of the blocks, a departure from initial plans.
“In some cases we have had to put in two sets of doors – one that satisfies thermal requirements and another that meets the required fire performance”
Natalie Armstrong, Galliford Try
“We didn’t look at precast concrete,” Mr Woolley reveals. “It was a commercially driven decision. The cast in-situ concrete frame meant that we could get on with the work quickly. We thought about using timber-framed systems for the penthouses but the client wasn’t keen, so we swapped those for the lightweight steel frames instead.”
The reinforced concrete floor slabs are generally 275 mm thick, although this is stepped up to 325 mm where they are supporting masonry or the balconies that each apartment boasts. As well as these balconies, the development features some semi-external ‘winter gardens’. These have proved challenging for the designers, as they needed to satisfy conflicting energy efficiency and fire resistance goals (see box).
There is plenty of laydown space across the site but its geography and the build programme has meant that only one 65 m jib tower crane has been available to service the project throughout. Even this has been unable to reach some parts of the scheme, with extra 150-tonne mobile cranes being brought in to help out when required.
“We have had to supplement the tower crane but we knew that would be the case,” Mr Woolley says. “It’s just something we have had to work around.”
Much more than a care home
The completed apartments will feature mechanical ventilation with heat recovery (MVHR) systems throughout. These offer a low-energy ventilation solution that supplies and extracts air from the buildings, capturing and re-using as much as 95 per cent of heat that might normally have been lost.
Galliford Try Longbridge Village 3
These are just one area where the client is determined to make the completed scheme affordable and workable for residents. Kitchen windows that overlook the wider, shared central corridors will give residents a visual link to their neighbours and all the apartments will be fitted out to the latest technological specification and the entire building is aiming to achieve BREEAM Very Good.
“Extra Care is determined that the completed scheme doesn’t have that ‘care home’ feel,” Mr Woolley says. “It wants to create a new community here and needs to show that these developments are possible without compromising on standards. We are trying to show that high-end retirement communities are achievable.”
Without a doubt the new retirement village will add to a Longbridge community gradually evolving from forgotten car factory to vibrant village.
Inside-out sections cause double trouble
Within the final layout of the Longbridge Retirement Village design are several glazed ‘Winter Gardens’ that are incorporated within the structure.
Steel-glazed frames are built within the buildings to provide a light, bright transition into the main buildings.
These areas have created a few challenges for the design and construction team as they try to steer the project through the technical and legal requirements.
Although facing onto the enclosed glazed gardens, the walls, windows and doors onto these sections are deemed to be external in terms of their required thermal insulation performance. Yet when looking at the potential for fire and smoke control, these same areas require internal levels of protection.
“In some cases we have had to put in two sets of doors – one that satisfies thermal requirements and another that meets the required fire performance,” Ms Armstrong explains.