Contract West Hertfordshire Hospitals emergency services centralisation
ClientWest Hertfordshire Hospitals NHS Trust
Contract value £25 million ProCure 21 contract
Main contractorMedicinq Osborne
Subcontract Watford General Hospital Acute Admissions Unit
Value £12 million
AAU PilingCentral Piling
AAU GroundworksHarrington Builders
If you are driving down Vicarage Road in Watford you might just catch part of the latest development work at Watford General Hospital.
Here client West Hertfordshire Hospitals NHS Trust has called in contractor Medicinq Osborne to deliver the largest Acute Admissions Unit in the UK as part of a £25 million hospital improvement project.
Try not to blink though. If you do you might just miss the new four-storey unit being built.
In a bid to limit time spent on site and slash the overall project time, Medicinq Osborne is using steel modules, prefabricated in North Yorkshire, to construct the facility.
As part of a £12 million subcontract, modular building specialist Yorkon will be craning completed sections of the building into position and stacking them on top of one another to complete the centre’s superstructure. In a month.
Of course there are other areas of the building that will need completing, but in effect the whole unit will be standing in less time than it takes to neg-otiate the Watford ring road.
Why use off-site methods?
Off-site building methods are paramount in saving this amount of time and, once the project had been given the go ahead, no other method was even considered, says Medicinq Osborne operations manager Stephen Cottrell.
“We saw right from day one that modular construction was the only way we could get the building built efficiently. There are constraints on the site. It is quite tight anyway but we didn’t want to disturb the day-to-day running of the hospital either,” he explains.
By using prefabricated steel modules rather than traditional building methods Mr Cottrell estimates at least three months has been lopped off the construction period.
“It could have been built using traditional methods but it just wasn’t practical here,” he adds.
Chris Langley, Yorkon operations manager for the Watford AAU project agrees.
“Our systems are ideal for this project. What off-site production offers is greater manufacturing efficiency. From the word go we have been able to bring in integrated design teams to make sure we can provide exactly what the client wants,” he says.
When completed, the AAU will be a stand-alone unit capable of working independently from the main hospital.
The 142 steel-framed modules Yorkon will erect will house 120 emergency admission beds, two cardiac catheterisation laboratories, a diagnostic centre - including x-ray, ultrasound and CT scanning - as well as the hospital pharmacy and library.
But the sensitivity of some of the equipment being used in these facilities has meant that not all of the final building will be built off site.
Continuous flight auger piles and a series of ring-beams linking around the development have been placed by piling contractor Central Piling and groundwork specialist Harrington Builders.
The Yorkon system has the ability to iron out any inaccuracies introduced during the casting of the foundations, but according to Mr Langley there has been no need to resort to remedial measures on the project.
“Nowadays the foundations are cast extremely accurately. It is feasible to do some shimming if needs be, but that is rarely the case,” he adds.
As well as the piles and foundations, a single story reinforced concrete transfer platform has been cast in situ to help deal with the vibration that could adversely affect some of the more sensitive machines in the unit.
“It is something that we had to design for,” says Mr Langley. “In all there are only six modules that have been affected by the transfer platform.”
But it has proven to be vital in the laying out of the modules as they arrive on site.
Once the transfer platform and foundations have been placed, the platform acts as a datum point for building the rest of the structure. Once this has been set the construction should prove relatively easy, explains Mr Langley.
“If we take the transfer platform as a set point of datum then everything else will be placed relative to it. We placed the modules in a ‘U’ shape, starting at the transfer platform and working back round to it,” he says.
Once this base level of units is successfully and accurately resin-anchor bolted into place any other floors are easily lifted into position by the 300 tonne mobile crane and fixed onto the module below using a bolted connection.
The primary beam at the upper level of the lowermost module is fixed to the bottom primary beam of the uppermost. At the end of the beam a flange plate is connected to the columns.
The 300 mm deep galvanised steel channels used to manufacture the modules act as ‘I’ sections when connected to the adjoining module and, despite the ability to vary the size of the steel used, Mr Langley claims the nominal 300 mm sections provide the best results.
“It could be a bespoke design using other sizes of steel, but then you lose some of the benefits of off-site manufacturing. To be able to standardise is a huge advantage to us,” he says.
Another advantage is being able to get feedback from the building’s end users before it has even been placed.
Yorkon and Medicinq Osborne bussed up a selection of doctors, nurses and other medical staff who will be working in the completed building to its production centre near York.
Here they were able to take on board the layout of the new building and also suggest any tinkering that may offer a better final product.
Fortunately the team of end users seemed pleased with the building and no serious changes were demanded, but it is because of the manufacturing programme - which sees the buildings erected at the -production centre - which allows this sort of feedback, Mr Langley explains.
Each module is completely fitted out - with pipework, plumbing and electrical installation all done.
All that has to happen once they are on site is to connect up these fittings. But in order to ensure the continuity of the fit-out phase the plastering and prefabrication work is carried out through each level of the building as it moves through the production line.
And by pre-erecting the building it allows the site team to call off each storey height as it is required - there’s no awkward stockpiling of modules in the yard.
“We carried out a complete logistical survey of how we were going to deliver the modules,” says Mr Langley, “They leave York at hourly intervals, which should ensure we can have one being craned, one prepared for lifting and two waiting on site. On average we have been bringing down 10 modules a day,” he says.
But with Yorkon programmed to take just 24 weeks to deliver the new AAU, surely there must be some short cuts being taken somewhere? It is a suggestion both Mr Cottrell and Mr Langley rebuff immediately.
“Yorkon will be manufacturing, installing and cladding a new unit that will comply with all the relevant regulations and those of the hospital management board,” says Mr Cottrell. “This will be a robust building with a 60-year design life.”
“What we are doing here is erecting a building using a volumetric structural steel frame, but we are bringing it to site in 3-D mode rather than 2-D. It is a proven engineered system,” says Mr Langley.
And a proven system that will see the Yorkon team hit its August completion deadline.
Try not to blink.
Delivering a healthy future
The project that both Medicinq Osborne and Yorkon are involved in is Phase 2 of a bid by client West Hertfordshire Hospitals NHS Trust to update its patient care facilities.
By the end of 2015 it is planned that a completely new hospital will stand at the Watford site, but prior to this some of the Trust’s facilities will have to be centralised as part of the project.
The £25 million ProCure 21 project that Medicinq Osborne is currently involved in includes the £13 million being spent on refurbishing existing facilities, increasing the number of intensive care beds, expanding the Accidents and Emergency department and also the Children’s Emergency department. Other parts of the scheme will see the project team create new car parking areas and reshuffle the overall layout of the hospital site.
“It’s not just the AAU that Yorkon is putting in here that is important,” says Medicinq Osborne operations manager Stephen Cottrell, “The rest of the scheme is vital to the overall delivery of the client’s plans.”
Planning the transportation of the modules
The thought of transporting 142 steel framed modules, each measuring 14 m x 3.3 m, down the M1 from North Yorkhire to Hertfordshire would send palpitations through even the most relaxed of traffic planners.
But the Yorkon and Medicinq Osborne team have gone to great lengths to ensure the delivery of the units has been as smooth as can be expected.
The site is on the doorstep of Watford Football Club and the ground it shares with Guinness Premiership rugby union club Saracens means that almost every weekend there are crowds to contend with and its proximity to Central London means at stages of the day traffic can be almost impossible.
To combat this, the modules were driven from the Yorkon factory every hour in the correct order to be lifted into position on site. Should any problems crop up on the way then the drivers would be directed to the Toddington services just a few miles north of Luton on the M1.
Here they were held until the problems have cleared and they can be called on one by one.
“We had to carry out a complete logistics survey for there delivery,” says Yorkon operations manager Chris Langley, “we have worked closely with the police and highway authorities. They will give us guidance and so far it has worked well.”