30 March 2009

Bridges news roundup

Not much happening at Happy Pontist Towers right now ... I've a review of Peter Bishop's book "Bridge" in the offing, and another handful of bridge competition debris posts planned. Hopefully in the near future the losing entries to the Leicester River Soar and Dublin River Liffey bridge design competitions will be made public. There should also be announcements made of the winners in design contests in Rhyl and Worcester any day now.

Is there bridge news you think I should be covering? If so, post in the comments here.

Meanwhile, here's a quick news roundup to keep things ticking over ...

Naeem Hussain interviewed on Third Forth Crossing
Great to see a bridge engineer the focus of attention

Civic Trust Award for Castleford Footbridge
Partnership award for S-shaped structure

Supplied Clyde Arc hanger forks met specification
Claims Macalloy

Hakes bridge design takes it to Moscow
Pontist notes cat's cradle design to be inefficient but couldn't summon energy to comment further

20 March 2009

Bridge competition debris part 12: River Wear

The River Wear Crossing bridge design competition will need little introduction to regular readers: I've covered the outcome extensively on several occasions here.

Organised by RIBA on behalf of the regeneration company, Sunderland Arc, the competition sought a design for a highway bridge across the River Wear, with the organisers being quite explicit that they were looking for something iconic. The winning design (pictured right), by Techniker and Spence Associates, is currently undergoing further technical development before Sunderland City Council decide whether or not they can afford it.

I've been keen for some time to publish the other entries, the five designs that weren't chosen. H0w is the winner to be properly judged if not against its peers? Sadly, Sunderland have refused to release images of the other entries, and my enquiries with the designers have, with the two exceptions shown below, drawn a blank.

Three losing entries came from Halcrow, Flint and Neill, and Dissing + Weitling; Hyder and Yee Associates; and Jacobs Babtie, Leonhardt Andrae und Partner, and Marks Barfield. I would love to show you these, so if any of the designers would like to send through their images, please email happypontist at googlemail dot com.

The other two losing entries are shown below courtesy of Schlaich Bergermann, and Wilkinson Eyre. How do they compare against the winner?

In many ways, all the designs share a desire to adopt an unnecessary and inefficient structural form purely to shout "look at me". That's not unreasonable - I think it's a large part of what Sunderland were looking for.

The Gifford / Wilkinson Eyre design is far more economic than the winning entry, with a cable layout that doesn't impose too many unnecessary forces on the support tower, particularly in the way the cables are arranged in plane with the axis of the V-shaped pylon arms (minimising bending moments).

That V-shaped pylon itself, of course, runs the risk of being seen in Sunderland as a two-fingered salute to local rivals such as Newcastle - see, our bridge is bigger, better. I can't help thinking the basic geometric idea (the X-shaped pylon and cable arrangement) doesn't quite make sense here, but could be developed into something interesting on a different site.

The images of the Schlaich Bergermann entry are a real curiosity, as much for the insight into their creative process as for the unlikely solution itself, a combination asymmetric cable-stayed suspension bridge, from which giant glass scales are suspended. Gehry doesn't strike me as an architect with much sympathy for the normal imperatives of bridge design - his work is about shape and surface rather than structure, and his non-linear, protean forms are at odds with the linear, refined forms normally suited to bridges. Jörg Schlaich, on the other hand, is a giant of engineering notable for pushing the boundaries of structural innovation without normally departing from the primacy of his structural ideas.

The Gehry / Schlaich design for River Wear seems to have its origins in Schlaich's 1989 Neckarstrasse footbridge, albeit at a larger scale and with the reverse suspension cable (the one that curves out of the tower like a letter D) much improved in shape. The only similar design I can recall seeing is Robert Benaim and Powell Williams's design for the Royal Victoria Dock bridge. Like that bridge, my first thought is about the difficulty of cable replacement once in operation.

Gehry's glass scales simply aren't my cup of tea, they seem like an afterthought, and I can easily imagine the judging panel worrying about both how they'd be restrained, maintained, and protected against damage. I do, however, admire the way that Gehry brought something so unpredictable to the design.

So, if you had to choose between these three designs, which would you choose, sat in Sunderland's shoes?

As with all these posts, click on an image for a full-size version.

Gifford / Wilkinson Eyre

Schlaich Bergermann / Atkins / Gehry Partners

18 March 2009

Squiggly bridge unveiled

The Broomielaw-Tradeston Footbridge has been unveiled in Glasgow, with the shrouds which were present (pictured below left) while it was welded and painted removed last week (pictured right). It won't actually open to the public until May, but the video at STV's website gives some idea of what to expect.

The design, by Halcrow and Dissing + Weitling, won a design-and-build competition in the aftermath of the failed "glasgowbridge" competition. It was far less ambitious than the entries to the original competition, representing a much more sober, risk-averse approach to the crossing.

In the time of the credit crunch, the bridge looks somewhat forlorn (an impression enhanced by STV's melancholy video soundtrack). There was always doubt about whether this bridge actually led anywhere (in theory, it's to help regenerate the south bank of the River Clyde, but until the regeneration happens there's little to go and see). However, until the wider economy recovers, it's likely to look like something of a white elephant. Unlucky timing for a bridge meant to provide the area with a sense of excitement.

The lack of colour, and the pristine joint-free surfaces to the steelwork (see picture, right), give an air of artifice rather than robustness - to the layperson, the bridge might just as well be made of plastic, with so little evidence of its making. The arrow-head towers are basically cable-stay bridge towers, with the stays replaced by box girders in order to provide sufficient restraint to an ultra-thin deck that is curved (hence "Squiggly") in plan.

The geometry of the various arrowhead surfaces seems designed to bring it to a point at its tip, while keeping steelwork in simple planes for ease of fabrication. But the effect looks a little odd, especially on the shaft of the arrow, where the box member walls taper in different directions. I find the connection of the "stays" to the deck a little peculiar too, likewise the way in which the arrowheads offer only a very limited visual response to the curvature of the deck (compare for example the more dynamic pylons on the South Quay Footbridge in London, especially in its original full S-shaped configuration).

The use of box-girder stays instead of cables might present a tempting target to Glasgow's skaters, climbers, and drunks. I'm not sure whether the curved notch at the base of the "stays" (pictured left) is intended to try and reduce this, but it will be interesting to see how well it works in practice.

I admire the minimalist simplicity of the design, while longing for the far greater sense of occasion that the original competition entries generally offered. Only time will tell what the Glasgwegians think of it.

16 March 2009

Bridges news roundup

US$6m signature bridge in Cleveland to go ahead
Rosales and SBP make start 6 months after appointment

Portland Tri-Met bridge bones picked over
Rosales and SBP subject to lengthy analysis, SBP designer enters debate (in comments to linked blog post)

One of our bridges is leaking
Listed Grade I Devils Bridge in Kirkby Lonsdale struggling to raise funds

Calatrava Bridge in Dallas hits snags
Margaret Hunt Hill Bridge (pictured left) finds sand may affect flood defences

Decision on River Wear crossing still uncertain
But approach roads to start design in September

12 March 2009

Hands off my bridge, it's a work of art

Imagine you own your home, and you've just embarked on a small building project to add a little extension out the back. Perhaps you're after a bigger kitchen, or to add a play room for your kids.

Your extension is completed, and you enjoy it very much. Until, that is, you find in the post one day, a writ from the designer of the original house. She claims that your extension is a mutilation of her original design, and asks the court for damages to restore her reputation. You are, I would guess, flabbergasted. It's your house, after all. Who is she to say you can't alter it as you wish?

Far fetched? Just plain weird? In Britain, it would be impossible, but that isn't the case everywhere.

For the last two years, Santiago Calatrava has been fighting just such a case against the authorities in Bilbao. The case relates to Calatrava's Zubizuri ("white bridge" in Basque), perhaps better known as his Campo Volantin Footbridge. And the news, just in, is that he has won. He's the designer, and no, it can't be altered without his consent.

Opened in 1997, the arch footbridge (pictured left), spanning 75m across the Nervion River, is one of Calatrava's most iconic works. It has had its problems - the footway is inset with glass bricks which can be slippery with wet, and the local council has reportedly spent 250,000 euros replacing them when they break, as well as dealing with claims from injured bridge users.

In 2006, a new and substantially less attractive footbridge link was added at one end of the Zubizuri, in order to provide a better connection to the new Isozaki towers. The new link bridge can be seen here and here (and below). While it's undoubtedly totally out of keeping with Calatrava's design, it does serve the rather useful purpose of providing a direct high-level connection where there was previously none.

In 2007, Calatrava sued the authorities for breaching his moral rights to the integrity of his artistic work, arguing that this alteration represented derogatory treatment of "his" bridge. He complained both about the attachment of the new bridge, and about the removal of a short section of balustrade. He sought either for the new link bridge to be removed (and to receive 250,000 euros in moral damages), or if it were to remain in place, to receive 3 million euros in damages, a sum that must have several other bridge designers wondering how they can tap this unlikely new source of income.

Bilbao argued that there was a common public interest in extending and modifying the bridge, and that this superseded Calatrava's rights.

In November 2007, the courts decided that although the designer's moral rights had indeed been breached, no damages were due. Calatrava appealed.

Now, Calatrava's appeal has been upheld, and while Bilbao will be allowed to keep their footbridge extension (pictured left, courtesy of Daquella Manera on flickr, as is the image below), they have to pay Calatrava damages. That link suggests 300,000 euros are to be paid, but in fact it's only 30,000 (Spanish readers can find the full court decision online). What's clear is that while the Spanish courts have very firmly upheld Calatrava's right not to have his bridges tampered with, they've also very firmly rejected his estimation of the extent of damage caused. Nonetheless, building owners throughout Spain will probably be reeling from the judgement, which opens the way for any architect to seek damages any time their work is altered.

So, what are these "moral rights"? They relate to the ability of an artist to control the fate of their works. Essentially, they prevent owners of a work of art from altering it, which I guess is a useful protection to have.

In the USA, moral rights are primarily available for visual art - certainly not for buildings.

In the UK, moral rights are enshrined in the Copyright, Designs and Patents Act of 1988, which includes buildings as "artistic works". Artistic works are protected against addition, deletion, alteration or adaptation, where this distorts or mutilates the work, or harms the creator's reputation in any way. Luckily for building owners in the UK, however, the Act specifically excludes buildings from protection against derogatory treatment (clause 80(5), for those who care), so it appears that the Calatrava case couldn't happen here.

In reality it's not quite that simple. A detailed account of the Calatrava case at WIPO magazine suggests that the Spanish intellectual property law doesn't clearly offer any protection to works of architecture, implying that the courts are setting an important precedent by expanding its interpretation. All national legislation in this area has its source in the Berne Convention, which does explicitly include works of architecture, and explicitly provides protection against distortion, mutilation or other derogatory treatment.

So it's far from unreasonable to conclude that this may not be the last time a bridge designer sues to protect the artistic integrity of their work. Bridge owners everywhere, beware! And homeowners, especially in Spain, think twice before having that extension built ...

07 March 2009

Farewell to wave bridge

I've previously discussed proposals for a new light rail bridge in Portland, Oregon, carrying the proposed Portland - Milwaukie line across the Williamette River. The point of interest has been architect Miguel Rosales' promotion of an innovative, risky "wave frame" bridge design (pictured above left) as a substitute for the more conventional cable-stayed design that otherwise seemed likely to prevail (pictured below right).

The process for selection of a preferred design seems so byzantinely complex and bureaucratic as to beggar belief. Nonetheless, I gather that it's far from unusual in the USA, where public participation in bridge design seems frequently to be allowed to trump the vision or wisdom of experienced professionals.

The bridge is being promoted by a body called TriMet, and it's worth reading the documents on their website both to marvel at how no firm decision has yet been reached after six months of incredibly detailed debate, and to see how, even when the options should in theory be narrowing, yet more choices are in fact being added to the mix.

The Portland press implies (without stating it explicitly) that Rosales preferred "wave frame" bridge has bitten the dust, with extensive cost studies confirming that it is both far more expensive and more risky than the obvious cable-stayed rival - US$145m for the wave-frame against US$91m for the cable-stay (pictured left). While it's a shame that cost gets in the way of innovative and aesthetically conscious bridge design, the Portland to Milwaukie light rail scheme seems to be struggling to get its budget to add up at all, so it's clearly not the opportunity to place ambition and aspiration ahead of common sense. I can't imagine how an extra US$50m could ever be justified for a bridge of this scale and function.

The cable-stay proponents have recognised that their design visualisations were somewhat unattractive, and have now presented a hybrid solution, combining the attributes of a cable-stayed and a suspension bridge (pictured, right, and below).

This is definitely a softer, more touch-feely alternative to the angular cable-stayed option, and harks back to designs like the Albert Bridge, Brooklyn Bridge, and the Niagara Railway Bridge. So, in search of an efficient, modern, visually appealing bridge, they've stepped back in time by about 150 years.

What's especially unclear is how they reconcile their desire for this visually attractive hybrid bridge with the desire for a least-cost solution: adding a main suspension cable to what was a perfectly functional and efficient cable-stayed bridge can only bump up the construction costs by a significant margin.

There's a reason they don't build them like that any more, after all.

The cable-stay option, which is undoubtedly the most efficient design for a light rail bridge spanning 200-250m, never seems to have been given the attention it deserves - the visualisations, with their classic A-frame design, do nothing to show how flexible this form is aesthetically, how many ways there are to make it attractive without having to go to the expense of Rosales' "wave-frame" solution. I don't get the feeling we're anywhere near seeing the final design yet ...

03 March 2009

Bridges news roundup

Anglo-Deutsch team wins in Leverkusen
Knight Architects and Knippers Helbig win bridge design competition, pictured right (more)

New journal offers historical perspective on bridges
ICE's "Engineering History and Heritage" includes articles on Thomas Telford and the lessons learnt from bridge failure in the UK: free sample issue available online

Trunk routes proposed to save elephant lives
Jumbo size flyovers required in India (spotted thanks to Bridgeworld.net)