Bringing costs under control on a leading edge architectural design, such as the new building for Queen Mary鈥檚 Hospital, presented a particularly difficult challenge, as Graham Ridout found out from the project team involved

Long before work began on architect Will Alsop鈥檚 stunning design for the advanced medical research centre at Queen Mary鈥檚 Hospital in the east end of London, the 拢45m project was facing a serious problem. Initial cost estimates were around 拢5m higher than the budgeted sum.

Hauling the scheme back within budget without compromising the design was to prove a hard slog, but one that was aided by some imaginative thinking.

Main contractor Laing O鈥橰ourke was appointed in late 2001, first to undertaken pre-construction works including demolition, and then given the remit of bringing cost certainty to the project. Laing鈥檚 project manager Peter Taylor recalls: 鈥淲hen we came aboard, there were elements of the design that were very well progressed and what we were realistically hoping for was to get cost certainty on 85% of the works packages.

鈥淚t was obviously a difficult situation because it was an estimate and we were assuming that we knew what packages would make up the 85%. The hardest bit was the design hadn鈥檛 been finalised so we didn鈥檛 really know what the final 15% was. And the final 15% is usually packages like finishes, sundry metalwork and elements like that which can have a percentage area of growth of around 25%.鈥�

To set the ball rolling, Laing hosted a one-day value engineering workshop that was attended by all the key players. Chris Webb, who headed cost consultant Turner & Townsend鈥檚 involvement on the project, explains: 鈥淚t was a very long day. We ran through the various elements and looked at the choice of materials, methods of construction, and loads of other details. Having Laing on board meant a lot of the focus was on the substructure and concrete works.鈥� (see box: Structural savings)

Webb continues: 鈥淲e went through the packages and set value targets for them. Someone was allocated for each package to manage the value engineering and evaluate what would be the implications if the design was changed. All the items were then catalogued and entered on a value improvement spreadsheet.

鈥淥bviously with such a landmark building, there were certain features on the architectural side that were untouchable for both the client and Alsop.鈥�

Simon Carter, Alsop鈥檚 project leader on the contract, says a lot the value engineering centred on the highly complex services required within the building, which accounted for approaching 50% of the total cost of the project.

Carter says the value engineering exercise succeeded in reducing costs significantly, especially in the space required for all the plant. Originally around 45% of the building鈥檚 total floor area was given over to plant, but Carter says this was reduced to 40%. Another result of the value engineering sessions led to reconfiguring the glass pavilion into two levels and making it much more open-plan. The pavilion rises above the basement laboratories and contains office space for the laboratory technicians and university staff as well as the four spectacular pods that are used as function rooms. Carter estimates around 拢1.5m was saved by the reconfiguration.

An unspecified amount of money was also trimmed off the fit-out costs of the laboratories by substituting conventional long benches rather than Alsop鈥檚 original propeller-style arrangement with three benches radiating out from a central point.

More savings were made by making the basement more open-plan than originally envisaged. Carter notes: 鈥淲e got a lot of efficiency there by breaking down the number of dividing walls required.鈥�

Both Laing鈥檚 Taylor and T&T鈥檚 Webb concur with Carter when he says the project benefited from having a relatively long pre-construction phase of around one year while the finance was being finalised. This gave more time to carry out value engineering. Even so, Taylor observes: 鈥淵ou need to close the door on value engineering at a certain stage. At Queen Mary鈥檚, we did further value engineering and it came back and bit us because it would have cost us more money. You have to be quite robust and say 鈥榮top now鈥� because after that stage the only real savings are deletions.鈥�

Structural savings

Around 拢150,000 was saved by redesigning the retaining walls of the basement. Originally, concrete secant piles were suggested, but Laing redesigned the basement to take steel sheet piles.

To peg the cost of props needed to restrain lateral movement of the sheet pile walls while the basement was being excavated, not all the ground was removed in one go. Instead, a strip of earth was left around the inside perimeter of the basement to support the sheet piles. This eliminated the need for large steel props criss-crossing the basement to stop the sheet piles moving. Large areas of the concrete floor slab of the basement could then be poured. Afterwards, smaller props were then anchored to the slab to support the sheet piles and the remainder of the excavation completed, before finally concreting the areas where the strip of earth had been.

A further 拢70,000 to 拢80,000 was saved by not having to pay for disposing of the spoil to a landfill site. Thanks to the underlying ground containing gravel, the material was sold to a local ready-mixed concrete company, which then used it in concrete mixes supplied to Queen Mary鈥檚. Laing鈥檚 Peter Taylor remarks: 鈥淐ost-wise, it was very good in terms of what we saved in muck-away, but it was also good for the environment.鈥�

Another major departure in the structural design was changing some of the floor slabs from conventional reinforced concrete to a post-tensioned concrete solution.

The change meant that the undersides of the floors were flat and not peppered with downstand beams, as is the case with traditional reinforced concrete slabs. Taylor observes: 鈥淗aving a flat slab makes installation of services that much easier, but it is very difficult to put a value to that.鈥�

Pods

Costing something that has never been designed or built before is always going to be tricky. Even more so when it is something as unusual as the striking and geometrically challenging 鈥淐entre of the Cell鈥� pod that is used as a 30-seater reception area for visitors.

The basic geometry of the glass reinforced plastic clad pod is ellipsoidal with 17 protruding hemispherical domes.

Allan Curtis, managing director of the pod鈥檚 contractor Design & Display, remarks: 鈥淏ecause it is such an unusual feature, it was difficult to put more than an indicative cost until we did a lot more work trying to understand how we could make it and put it together.鈥�

While liaising closely with architect Alsop, D&D set about undertaking an in-house value engineering exercise. The firm鈥檚 design manager Dick Kiss explains: 鈥淚t was a question of using paper and pencil and pure brainpower to decide the shape of the panels.鈥� Curtis adds:

鈥淚t was so complex that we couldn鈥檛 talk about tendering without a scheme in place to build it.鈥�

鈥淓ven during the pre-tender discussions, cost certainty was
at the forefront of everyone鈥檚 minds,鈥� says Kiss.

Value engineering succeeded in producing the most economic number of moulds for the 90 grp panels that form the 550m2 envelope for the pod. The painstaking work paid dividends and D&D won the competitive tender with a bid of around 拢250,000.

Source

QS News