River Wear Bridge controversy linked to IABSE competition guidelines

"When engineers get the knife out they can be worse than architects". So says an editorial from Paul Finch in this week's Architects Journal. Finch suggests that "all is not happy in that part of the engineering world which still believes that dreary Freeman Fox box girders were all that were ever required."

The target of his scorn is criticism by bridge engineers of the design for the New Wear Crossing in Sunderland (pictured). The scheme, which has experienced a history of uncertainty dating back to the original bridge design competition, has recently suffered a major blow when two of four tenderers pulled out, almost certainly because of the difficulties determining the cost of building such an unusual structure with sufficient certainty.

Finch asserts that criticism of the "handsome-looking" bridge has been "aggressive" and "moaning", going on to request that "serious competitions with serious winners should not be the subject of professional sniping."

Really? How absurd. Perhaps an appropriate title for this blog post might be "When journalists get the knife out they can be worse than engineers or architects", and perhaps a humble blogger might suggest that "serious engineers should not be the subject of sniping from amateurs".

Although never named, the target of Finch's attack is Simon Bourne, probably the only engineer willing to have his name publicly attached to criticism of Sunderland's vanity project. He has gone on record at least twice. I reported the first occasion, when he told New Civil Engineer that "the bridge is about as structurally inefficient as you can imagine", which strikes me as essentially uncontentious. Two other, anonymous, engineers were happy to attack the bridge at the same time, and these views are consistent with most if not all of those which I have heard privately from other bridge designers. Bourne's more recent comments, in response to the withdrawal of two tenderers, included saying that "the risks of its hugely unique nature are very profound", which strikes me merely as a statement of the obvious.

In Finch's world, engineers should presumably just shut up and fall in line, leaving architects to do the talking. As I've discussed here before, deafness to criticism aligns closely with clients buying closely into a designer's vision, blind to its faults or at least to its risks. At least one high-profile UK bridge design contest came to a miserable end as a result, with a structurally exotic proposal remaining unbuilt, and it's now increasingly possible that the same will happen in Sunderland. Criticism should be welcomed: if a project is well-thought through, responding to challenge will only make its case stronger. What is less helpful, and Bourne's comments fall into this category, is criticism which comes too late to actually make any difference to the decision-making. Participants at all levels have too much personal investment in a project, and positions are too entrenched to change. Careers are staked on making a project succeed, whatever it takes, regardless of whether simpler or better-value alternatives have been discarded along the way.

Finch's attack on honest criticism doesn't end there, however. He goes on to link his point to IABSE's Guidelines for Bridge Design Competitions, which were published earlier this month. This is a document which grew out of widespread dissatisfaction with the conduct and outcome of design contests. In the UK, the subject was extensively aired at the 2007 IABSE Henderson Colloquium, with many of the lessons identified from failed competitions finding their way into the final IABSE guidance.

Finch points to an interview with Naeem Hussain, the chair of the IABSE bridge design competition working group, who discussed the guidelines with New Civil Engineer last year, prior to publication. Hussain was quoted by NCE as saying: "Some of the architects themselves are saying that the pendulum has swung too much and that designs are becoming so outlandish. First you often cannot build them or then the cost is so high that the client abandons the project." The IABSE guidelines are intended to assist clients in properly appraising proposals at the outset so as to reduce the risk of failure, and hence the risk of contest participants wasting their time and money.

In addition to a number of rather petty side-swipes at the content of the guidelines themselves, Finch suggests Hussain's NCE interview "reads like a thinly veiled attack on ‘arty’ structures." Finch isn't wrong to put his finger on the anti-expressive nature of many engineers, a belief instilled by their training and culture that value is the same thing as economy, and that measuring efficiency is tantamount of measuring virtue. I have limited sympathy with this reductionist vision of what bridge design can and should be, but nor would I suggest that the genuinely held views of acknowledged bridge construction experts should be discarded simply because a design competition was somehow "serious", as Finch does. Indeed, I think their views on the subject are probably better-informed than non-professional commentators.

A desire to silence engineering criticism has been reported within the New Wear Crossing's project team itself. In a talk by the design engineer Techniker, reprinted on their website, you can find the following: "One engineering collaborator on the project simply had to go – [they] proved to be subverting the intentions of the designer as at odds with appropriate bridge design. This was a kind of negative professionalism, parochial and ingrowing." Perhaps this is the same anonymous party cited by NCE last year as 'an expert close to the project', saying: "It's a really complicated bridge, and completely unnecessary for a span of this length".

I would have to agree with Techniker, in part. If a professional firm engaged on the project is genuinely attempting to do anything other than use their best professional endeavours to help deliver the client's agreed vision, then they should not be there. The rest of Techniker's talk makes clear that their view is that this is a cultural problem, that many engineers are trapped in what Finch would parody as the box-girder mindset.

More of Techniker's perspective can be understood from a short blog post on their website, which claims that "with modern methods of analysis construction practicalities are receding into irrelevance and the architect is free to organise form as he/she wishes within the geometric constraints of stability." I imagine many contractors would beg to differ, not least the two who have withdrawn from the procurement process.

Techniker's view appears to be simply that some necessary material has been moved up into the sky out of the deck, and if you think I am caricaturing them, here is how they describe the design process: "We worked to justify our proposals as a bigging out of the required steel, spreading it across the sky to make an effect." This is the opposite of the traditional bridge engineering approach, which works from the constraints of the site and of the construction method to determine where material can most efficiently be used. Cable-stayed bridges, of which the New Wear Crossing remains at heart an example, are the epitome of this conventional approach, incorporating within their permanent form all the materials that are also required for temporary support. The River Wear bridge, by contrast, will require extensive temporary support during construction, as material has been disposed for primarily expressive rather than structural effect. Some of the consequences can be seen in Techniker's website postings, and also on their detailed design drawings, a grab bag of which have just been made public.

A departure from the ordinary engineering imperative can be economically justified wherever the outcome creates sufficient value to offset the additional expenditure. That's the argument made by Sunderland Council's leader, who in defending the iconic design makes a big noise about the whole scheme's benefit-to-cost ratio (BCR), which is over 4, and therefore far more positive than many other schemes which government is happy to support. The breakdown of the calculated BCR can be found in a document on the New Wear Crossing website (see in particular page 63).

This makes clear that nearly 90% of the expected benefit of the project relates to transport cost savings, with only about 10% relating to the "landmark" nature of the bridge scheme. Of that remaining 10%, the majority relates to the expectation that an "iconic" structure will attract more investment and create more jobs than a cheaper alternative, a belief widely accepted but one for which hard evidence is much harder to come by. What is less clear, and I have been unable to extract numbers from Sunderland's reports which test this, is whether the additional "landmark" benefit is commensurate with the additional cost of a landmark versus a cheap structure. On the figures presented, any "extra over" cost of making the bridge "landmark" rather than conventional, beyond an allowance of £8m, will actually imply that choosing a landmark has reduced the benefit-to-cost ratio of the whole scheme. It doesn't seem plausible to me that the "landmark" cost of this bridge (as against Paul Finch's hated box girder option) is that low.

Ultimately, this is one proper test of the design's appropriateness. Does it add a sufficient proportion of value to justify its cost? While the scheme's engineering critics are right to point out the risks and difficulties of taking forward such a monumentally unique design, they have little if anything relevant to say about the value of the resulting structure to Sunderland's economy.

In one of their website postings, Techniker assert: "We need to set up a critical framework for engineering." This is quite right. Such a framework won't be found solely in the engineering puritans' fear of extravagance; nor in the belief that the desire for economy is irrelevant in an era where anything that can be designed can be built. It certainly won't be found in a world where honest engineering views are dismissed out-of-hand by journalists as "sniping" or "moaning", nor one where IABSE's well-intentioned attempt to encourage better procurement is treated with unjustified paranoia.