Plans to build what could have been the most exciting public structure of the decade, Margate's Turner Contemporary art gallery, were given the chop earlier this month. The building, shaped like the conning tower of a submarine, was to have been anchored off the seaward face of Margate harbour's breakwater.
Client Kent County Council (KCC) had spent £6M on design over five years. But it decided to pull the plug after projected construction costs soared to £48M, 'without any assurance that the cost would not rise further, ' says the KCC cabinet member responsible for the project Mike Hill (News last week). This was nearly seven times the cost estimate in 2001, when the scheme was . rst conceived.
So when did Turner Contemporary run into problems?
The entire structural concept was changed from reinforced concrete to steel just after planning permission was granted. When KCC advertised for construction only two firms responded. And during the gallery's five year gestation three different firms of structural engineers have run their fingers over it.
Turner Contemporary was to be the beacon for regeneration of the rundown seaside town of Margate as well as a testament to 21st century engineering innovation. Architect Sn°hetta & Spence won a design competition for the gallery in 2001 with a proposal for a three storey building lying 8m outside the breakwater. It would be connected to an entrance foyer on the breakwater by a double deck bridge. The structure would have to withstand punishment meted out by breakers up to 14m high, sweeping up to almost half its height (NCE 15 January 2004).
In selecting Sn°hetta & Spence's proposition, KCC departed from its original brief: It had set aside an onshore site for the gallery. But the client was swept away by the design which was 'challenging, exciting and which released the area on land for parking', admits Hill.
Hill says that, with hindsight, putting the structure in the sea 'had the effect of sinking the design. It certainly gave us complications in the way the structure was to be engineered'.
The gallery was originally designed by structural engineer Jane Wernick as a £7M reinforced concrete structure with timber cladding. The advantage of using concrete was that it had its own mass [to resist the force of waves] and the timber could be allowed to weather, ' says Wernick.
As the project was developed to planning stage costs shot up, reaching £12.6M. And they leapt further after consultation with maritime engineers at Arup revealed that shingle swept up by furious winter waves would rip the timber cladding apart. The solution was to ditch the concrete and timber in favour of a steel frame with a resilient, painted steel cladding.
Wernick says she was forced to withdraw from the project for 'contractual reasons', and consultant Whitbybird took command in 2003.
Whitbybird developed the steel design, taking advantage of being able to prefabricate the structure and float it to the Margate site. This reduced some of the construction risk of building the gallery in the sea. But the project started to push the £17.6M mark as the design developed. Steel prices were rising. Meanwhile, with very much less mass than concrete, providing suf. cient ballast in the all-steel design proved an issue.
In July 2005, KCC was advised by its project manager Davis Langdon to procure the project as a design and build contract, deflecting design and construction risk away from the council. Just two offers came forward.
Contractor Nuttall was finally chosen. Wary of the unique design, Nuttall demanded that the contract be split into two stages.
The first involved developing the design to construction stage, assessing whether the scheme could be built for less than £29.5M, and developing a construction programme. Stage two involved actually building the structure.
Hill acknowledges that 'design and build clearly does make the contractor more nervous, especially on such an innovative building'. Nuttall's nervousness could only have been aggravated by Whitbybird's refusal to be novated to the contractor.
'We were advising against going down the design and build route [at Margate] because it was such a non standard project and costs would inevitably go up, ' says Wernick. Wernick was also structural engineer on the London Eye, which saw construction costs soar from £30M to £75M - she believes as a result of design and build procurement.
Hill confirms that at KCC concern grew over the cost of the gallery as the price of other high profile local authority projects mounted.
Portsmouth's Spinnaker Tower rocketed from £16M to £21M (NCE 29 May 2003).
Shouldering responsibility for design as well as construction, Nuttall employed consultant Scott Wilson and architect Broadway Maylan to review Sn°hetta & Spence and Whitbybird's design.
Whitbybird was unwilling to comment, but architect Stephen Spence says that Scott Wilson had serious technical issues with it and suggested starting design from scratch using more relevant design codes.
'Instead of re. ning the design they wanted to go back to first principles, ' says Spence.
But a source close to the project says that Scott Wilson's technical doubts were justified.
Risks associated with housing priceless art and members of the public in such a harsh maritime environment had not been properly addressed.
'During the last five years, the structure has been designed with all the sophistication of the hull of a ship, but not to the design standard needed for a public art gallery.' Construction costs soared to £33M.
Hill mourns: 'We used world class architects, contractors and engineers - we paid for the best, but unfortunately didn't get the result we wanted.' Having scrapped the offshore option KCC is going back to basics itself, with a new design including hotel and conference facilities, using its original on-land site. 'There is a sense of relief that we're now pressing ahead with something affordable, ' Hill says. But his relief is tinged with regret. 'There was outcry when the Angel of the North was going up in Gateshead. People were saying to the council: 'Why spend so much money on a sculpture?' But every one loves it now.'