Case study of the Museum of Liverpool

There must have been times when it looked as if it would never happen.

The main contractor on the Museum of Liverpool - a joint venture between Galliford Try and Danish firm Pihl - are well set to complete the building by June 2009, before it opens in 2010.

But it has been a long time coming. National Museums Liverpool originally bought a site at Pier Head on the edge of the river Mersey with the intention of building a museum back in the 1960s.

But it wasn't until almost 40 years later that the project received outline planning permission, in 1997.

And even then, it was a difficult birth. The museum was to sit at the centre of the doomed Fourth Grace project, which was intended to complement a trinity of Liverpudlian landmarks: the Royal Liver Building, the Cunard Building and the Port of Liverpool Building.

But "fundamental changes" to architect Will Alsop's original plan left it unworkable and it was abandoned.

Luckily, while much of the Fourth Grace was scrapped, the museum was still considered worthy of public funding and the idea was salvaged.

So far, so precarious. But even once the building had been given the green light, contractual negotiations did not run smoothly.

Laing O'Rourke originally won a two-stage tender on the job but agreed to part ways with the client after it decided that it had too much work on in the area, and the client felt it could get better value for money.

So it must have been something of a relief when Galliford Try and Pihl stepped in to pick up where Laing O'Rourke left off.

"We went to a negotiated procedure because the urgency of having a main contractor on board to hit our deadline was so critical," explains Sharon Granville, executive director of the Museum of Liverpool Project.

Galliford and Pihl, which had not worked in the UK before, performed well at interview, Granville says, and subsequently formed a joint venture to take on the project.

Galliford Try North's commercial director Kieran Brennan explains what happened next: "We were invited to bid on the second stage in October 2006. Prior to that, Pihl were looking for a contractor in the UK and approached us.

"We achieved about £4.1m-worth of value engineering savings because the project was over budget. Ultimately we agreed a price in March 2007 of about £41m and then we commenced the construction stage in April that year."

So after all that uncertainty, what of the building itself? The three-floor building is made up of a complex steel structure with cantilevers at both ends, in an X-shape.

Its foundations are now complete, with around 85% of the structural steel also in place, and just the cantilevers remaining to go in.

According to the seemingly unflappable Danish project manager, Pihl's Christian Lundhus, the most difficult parts of the build have already been completed.

"I would say that the most challenging aspect of the build has already been sorted out - that was the design for the temporary propping system for the steel cantilevers and the raft foundation," Lundhus says.

To construct the foundation, Pihl and Galliford Try, aided by Buro Happold, had to dig 4m into the ground and erect a network of 3.5m-high walls which form a series of cells, before laying a 300m concrete slab, which forms the basis of the ground floor, on top.

Underlying soil

Because the underlying soil is not, in Lunhus's estimation "the greatest in the world", the foundation will weigh no more than the ground that was excavated. The team also has to be careful not to interfere with a railway tunnel 20m below the site.

As for the structural steel work, Lundhus says that because of the amount of steel being used and the fact that nothing in the building is square, it was entirely modelled in 3D and fed into an automated system before its arrival on site so that there have been very few in-situ changes.

The next major challenge will be to put the two huge cantilevers, measuring 4.5m on one side and 8m on the other, in place. "The two cantilevers on each end have to be temporarily supported for a certain period of time. It's quite a heavy load and it's not a very stable structure. So by having the temporary supports there we ensure that it is stable before we cast the concrete floors," Lundhus says.

The support will come in the shape of two temporary towers in each corner of the site. On top of those will sit two 400t jacks so that the cantilevers can be released slowly. Such is the precision of the operation that they aren't expected to settle by more than 15mm when they are released.

"In order to carry out these works, we've had to have piles put in the ground in one corner and then we've had to cast pile caps. On the other corner of the site there's a relatively new culvert and unfortunately one of these temporary supports has to be right on top of that culvert. So in order not to affect the culvert structure, we have bridged it. So that has definitely been one of the main challenges," he explains.

As for the exterior of the building, it will be clad in Jura stone - a change to the travertine that was originally specified because Jura stone should stand up to the changeable Merseyside weather more effectively, as well as being easier to clean.

Spiral staircase

Finally, comes the 8m-wide spiral staircase, which will form an interior centrepiece. This will require its own specially designed formwork system and will have to be held in place for 28 days after the rest of the building has been completed while the concrete cures.

If all does go according to plan, and Brennan indicates that at this stage the project is running to time and budget, the building will be handed over in May or June 2009. There then follows a £24m fitout before the museum opens in 2010, which Galliford Try is also eyeing.

"We've expressed an interest and hopefully we'll be in a good position to do that," Brennan says.

And the client certainly seems happy with Galliford Try and Pihl's efforts so far. "They are very good to work with. We haven't got a formal partnering arrangement, but I think the relationship we have with them is as close as you would get," Glanville says.

"They have bought into the philosphy of the project. It's not like building another office block. They have got genuinely excited about what they are doing. People will visit this building in their millions," she adds.

Not a bad reward for the contractor that nearly wasn't on the project that nearly never was.

Project team

Contractor: Galliford Try in joint venture with Pihl

Engineer: Buro Happold

Architect: AEW

Project management: Osprey Mott McDonald

Cost managers: Turner and Townsend