10 September 2009

Horny bridge keeps on going

A proposed "iconic" bridge in Sunderland, designed by Spence Associates and Techniker, is moving forwards, following a meeting of Sunderland's city council cabinet yesterday. Claiming the structure would be a "people's bridge", the council leader revealed that the design is likely to be submitted for planning consent in November. The bridge features twin cable-stayed masts shaped a little like antelope horns.


A report available on the council's website makes for interesting reading, and is perhaps worth dissecting in some detail (just a dissection - not quite a full scale fisking).

It notes that "the design aligns with the City's brand values of 'smart', 'life-enhancing' and 'balanced'". I nearly snorted my cup of tea when reading that - what's so smart about a cable-stay bridge with no back-stays? It's balanced only in the sense that a man standing on one leg is balanced - he can stand up, but the effort to remain so is harder than it needs to be.

The report reveals that Techniker have now done considerable design development, backed up by peer review by their own subconsultants, consultation with possible contractors, and validation by the Council's normal cost and engineering consultants. It would be nice to know who the peer reviewers are, in particular, as they would be expected to include specialist long-span bridge engineers, but I can't imagine many of those wanting their names too closely associated with this design.

This is all very good - given the extravagantly unusual structural behaviour of this design, a detailed consideration of technical issues and risks is vital to confirming its feasibility and ability to be built within cost. The report certainly suggests substantial risk management is being undertaken. Hydraulic and wind tunnel testing have both been carried out.

The report still doesn't shed much light on the bridge's actual cost, reporting only the overall scheme cost of £133m, which include 3km of highway, land acquisitions, and utility diversions as well as the bridge itself. It makes clear that funding is not yet secured: the Department for Transport (DfT) have agreed £98m of funds, but those are dependent on construction tenders falling within the budget estimate. £6m comes from development agency One North East. The Council calculates it has to provide the remaining £29m of the total.

That's made up by sticking a £10m dent into their five-year Local Transport Plan funding (presumably that means cutting cycle and bus schemes), with the rest drawing down on the city's strategic reserves. Council tax payers therefore don't see any rise in their tax to pay for the bridge, but at the cost of exhausting considerable sums of money which could have been spent locally on other projects. It also means (as with many regeneration projects) that the Council financing is heavily geared, such that a 10% increase in overall scheme costs could lead to a near doubling of what the Council actually has to pay (although in reality some of that increase would be bailed out by central government). The risks to local finances are therefore not insignificant.

The report does give some simple dimensions for the bridge (336m long by 30m wide), which confirm that square metreage costs estimates I've previously made are based on the right information.


The document also suggests that there is evidence that landmark bridges accelerate and lead to higher quality regeneration and development in their vicinity. This is the assumption made by most commissioning authorities, and it may well be true, but I've never seen any proper quantitative evidence to support it. In any event, greater development would need to be measured against greater cost to make a serious financial case for a landmark structure, a calculation yet to be made.

The cabinet report repeats the statement that "public opinion is overall in favour of having a landmark design ... and to do so while minimising the impact on council tax". This has been said several times in Sunderland, but I've noted previously that the council's own surveys tell a very different story, with half the populace preferring a "tried and tested" solution instead.

The report also offers insight into Techniker's appointment. The council have clearly considered the possibility that their appointment could be ended, with the remaining design carried out by another firm, most probably via design-and-build. The report states that "as this is a landmark design, Techniker have insisted that they must remain as the exclusive designers ... for the full duration of the design services".

It's good to see the designer taking such a strong position, as there have certainly been design competitions in the past where the original designer has been discarded in favour of others, perhaps most controversially on Stonecutter's Bridge. At River Wear in Sunderland, it would seem that Techniker retained design copyright throughout, giving them a strong negotiating position, even in the face of their very limited track record in designing major structures of this type.

So, the choice of bridge is now finally confirmed, four years after the Techniker design won in competition, and the next step is to secure all the necessary consents from statutory bodies and seek final confirmation of funding. I have to admit I thought this was a bridge that would never get built, and it's remarkable that such a bizarre design has survived the design development phase intact. The next real obstacle in its path is likely to come when construction tenders are submitted in 2011 or 2012, when we'll find out whether the budget estimates are right or not (for a classic example of another unconvential structure which failed at that hurdle, see the Neptune's Way scheme).

2 comments:

Anonymous said...

Recent reports on the project make no reference to the architect part of the competition-winning team, Stephen Spence, so it is not clear whether he remains involved, however it is gratifying to see the engineer resolutely defending the original concept as the design is developed.

The Happy Pontist said...

I had wondered what had happened to Spence. It's a key problem for architects in bridge design competitions - a high proportion of their work takes place up front, with generally far less to do later on, so unless they are well rewarded for winning the contest, it can be difficult for them to recover a proper fee. The consultant engineer has the carrot of the detailed structural design contract (no doubt one reason Techniker have fought against their design being handed over to a D&B consortium).