Sheffield Parkway Bridge revealed

Back in August, I wrote about Yorkshire Forward's decision to drop the RIBA-competition winning footbridge design from Ramboll and Tim Nørlund Jensen on the grounds that its cost had increased beyond the original £1.5m budget, and to replace it with a new design. Mr Jensen was not best pleased, believing he had carried out substantial design development on the original scheme, without ever being paid.

The "iconic" bridge design (shown right), was to span the A630 Sheffield Parkway near Rotherham, providing a new bridleway and footway route.

Now, the replacement design has been submitted for planning consent, and we get the chance to see whether, as one commenter on this blog previously asked, "an over-ambitious competition-winning showpony [has been] replaced with a cut price and cheap substitute." The full planning submission is available online [PDF].

The new bridge (pictured below) has been designed by Scott Wilson, and is a 49m span hybrid Vierendeel truss and bowstring arch structure.
The trusses are 3.5m deep, and made from circular hollow steel sections. It's somewhat similar to a footbridge over the A27 at Tangmere in West Sussex, although not identical: the web members are more highly splayed rather than arranged radially, it lacks the Tangmere bridge's peculiar secondary arch, and the opportunity has been taken at Sheffield to adopt a much more interesting parapet.

So, neither a showpony nor the cheapest substitute, there's a welcome desire to keep it a little more interesting than Yorkshire Forward's budget-consciousness might otherwise have implied.

A number of lessons remain apparent.

RIBA design competitions remain a poor way to get a bridge built, and competitors are accepting an incredibly poor investment-to-reward ratio. Of 393 entries to four open contests (New Islington, Bootle, River Douglas, Sheffield), only 2 made it to planning permission stage (New Islington, Bootle), and only 1 is actually being built (Bootle).

There appears to be little serious scrutiny of the likely costs of designs presented, with Sheffield being one of three recent RIBA contests (the others being River Wear and River Avon) where the winner was found to require far more than the original budget (in two other contests, New Islington and River Douglas, it's unclear if there ever was a real budget).

Promoters simply should not be going down this route if they either lack the money for their bridge, or are unable to sensibly select a design that meets their budget. The cost to the industry is enormous, and it appears that vanity and ambition have often trumped common sense.

See also:
Bridge competition debris part 3: Sheffield Parkway

Bridges news roundup

Second wobbly bridge for London
Headline writer gets wrong end of stick, shakes it vigorously

Safety alert closes famous bridge
Bolt failures on Middlesborough Transporter Bridge mean that all three surviving transporter bridges in the UK are now closed to the public (the others are at Newport and Warrington)

'Daring' Eagles Meadow bridge wins architectural award
Oddly no mention made of Wrexham footbridge's notorious wobbly tendency

1,000-year-old roofed wooden arch bridge - Wan'an Bridge in Pingan, China's Fujian
I've mentioned these on a previous roundup, but they're great, so here goes again

Hundreds of people to tour bridge
Anchorage chambers and tower tops of Forth Road Bridge open for special visits

Copenhagen bridge competition winners

Flint and Neill and WTM Engineers have been declared winners of a bridge design contest in Copenhagen.

The contest was in two parts: a 9.4m euro opening footbridge spanning 50m across the Inderhavnen (Inner Harbour), won by a design from Flints with Studio Bednarski; and further footbridges spanning Christianshavns Kanal and Trangraven, and across Proviantmagasingraven, won by a design from WTM with Dietmar Feichtinger Architects. There were eight other entrants, with many of the big names in landmark bridge design represented.

The new bridges provide improved walking and cycling links including to the recently completed Opera House. Their construction is being funded privately by the A.P. Møller and Chastine McKinney Møller Foundation, and they are expected to be completed in 2012.

The Inderhavnen structure has already been nicknamed the "kissing bridge" (see right, and below, click on images for larger versions). The two moving halves of the structure retract and extend longitudinally on support rails, like twin brachiosaurs bumping noses when they meet in the middle.

Retractile bridges are very rare, and this bridge will be a nearly unique structure when built. The point of support of the moving span continuously changes as the bridge opens, which normally makes the supporting structure over-heavy compared to a bascule, swing, or lifting bridge, where the reactions are generally carried directly at a bridge pier. Maintenance of the tracks may also be a concern, and the bridge will also be slower to operate than alternatives, as the main spans have to be jacked off their main supports onto the rolling tracks before operation. The jacks, and the interlocking mechanism required at midspan, all add to the likelihood that the bridge will be more expensive to maintain than alternative options. [But see Update below!]

Most retractile bridges are floating structures, where this isn't a problem, and where they can provide larger opening spans than the alternatives (as at the Hood Canal and Ford Island bridges).

In favour of the retractile bridge, the energy costs for operation should be less than a bascule, as the wind loads are much lower. And of course, it will look pretty cool.

The WTM / Feichtinger bridges (see right), which cross smaller arms of the harbour canals, are more conventional single-leaf and double-leaf bascule structures. These have no significant counterweight elements and appear to be supported in both open and close positions on their main hydraulic cylinders, a situation which is far from ideal. Although they're relatively minimalist in appearance, they seem somewhat unconvincing to me.

Several of the other entries are well worth a look, and you can find them online in the jury report at the Copenhagen Kommune website [PDF]. Regretably, I'm a bit too short of time right now to give them a thorough analysis here, but the jury report has plenty of detail on each design. The decision to publish the jury report is something that other competition organisers could learn from: the entrants (all ten of whom were paid a fee for their efforts) receive useful feedback; the scoring process is clearly set out; and the whole exercise is seen to be transparent and rational.

Updated 30 October: Since writing the above, I've been advised that some of the technical details given in the jury report for the Flints design have been changed during the negotiating stage of the contest. In particular, some of the operational aspects have been altered, such that the maintenance costs are likely to be less of an issue than I suggested above. Hopefully more details of the final design will become available in due course.

From the wider perspective, this willingness to fine-tune the design is another example of how sensibly the Copenhagen competition process has been arranged, compared to other cases where a design vision is seen as fixed on day one, despite the limited amount of time a competitor has been given to prepare it.

Bridges news roundup

ODA backs Arup bridges in face of criticism
“featureless, lacking in architectural character and visual interest” - ouch. Examples of CABE's critique of the Olympic bridges (see image on the right) are available online.

Bootle bridge underway
Softroom's RIBA contest-winning wooden bridge begins construction

Valencian architect donates damages to charity
Santiago Calatrava gives Zubizuri money (see my previous post for full details) to Bilbao charity

The wooden arch bridge needs urgent protection
Attempt to preserve traditional bridge-building skills in China

Eliasson to build bridge in Copenhagen
Artist wants pedestrians to come as close the the water as possible. Boats and surfboards apparently not an option? See previous bridge-related hi-jinks from the same artist.

Bridge competition debris part 17: Galp Energia Bridge

I wasn't previously aware of this recent competition to design a new foot and cycle bridge over a highway in Lisbon. It was run over the summer, promoted by Fundação Galp Energia, a Portugese gas and oil distribution company, and ExperimentaDesign, a biennale design exhibition. Open only to registered architects, the scheme proposed a bridge with a 1m euro budget, and the contest had a reasonable prize fund, with 20,000 euros shared amongst the winners.

The organisers received 62 submissions from 14 countries, and the results were announced a couple of weeks ago. I've included whichever images I can find online below. I've left all the entries without comment, so feel free to add comments below.

As always, click on any image for a larger version. Links are provided if the designer's website has more information on a particular design.

Winner
Telmo Cruz + Maximina Almeida + António Adão da Fonseca


Second
Moxon Architects Limited




Third
Impromptu Arquitectos + Selahattin Tuysuz Architecture (also at designboom)




Honourable Mention
Studio Kawamura Ganjavian


Honourable Mention
Atelier do Cardoso




Special Mention
Tiago Barros + Jorge Pereira (see Bustler and designboom)





Others
Filipe Melo e Oliveira + Madalena Caiado




Update 22 October:
Another entry:
Pedro Pimentel

Bridges news roundup

Infinity bridge scoops Structural Awards
Stockton-on-Tees structure wins Supreme Award for Structural Engineering Excellence, and Award for Pedestrian Bridges. More information including other award winning bridges here.

Wear icon bridge design changes and cost goes up
Preserving architectural integrity a snip at £7,500

Billion pound question over new Forth Bridge
War of words can't disguise genuine puzzle over how £2bn cost estimate has been arrived at

A high line park for San Francisco's Bay Bridge
Would you like to live on a used bridge? More at LiveScience.

Building a Bridge of (and to) the Future
NY Times reports on unusual arch bridge built using inflatable CFRP tubes

Dresden bridge has an unexpectedly high price
LA Times reports on the bridge that cost Dresden its UNESCO World Heritage status

Johnson Street Bridge update

Further to my previous post on this interesting moving bridge replacement project, the City of Victoria has been reconsidering its options. Faced with the lack of any federal funding for the CAN$63m scheme, the city council have backed away from the replacement decision and called for further reports. New options will include not replacing the rail span, saving $15m, and taking into account a report on refurbishment presented by the highly articulate protest group johnsonstreetbridge.org.