26 March 2011

Taunton's Third Way bridge installed

A new road bridge has been lifted into place in Taunton, Somerset. It spans 36m across the River Tone, and is part of a scheme to relieve town centre congestion. I believe the bridge cost about £1.5m, although a number of seemingly unrelated figures are reported online.

The designers of this attractive little bridge are Flint and Neill with Moxon Architects. The most obvious feature is the pair of trussed arches, a little reminiscent of Flint's masts for the Lockmeadow Footbridge.

Each arch is triangular in cross-section, with four ribs braced apart by Vierendeel-style frames. There are two circular ribs at the upper corners of the triangle, and two rectangular ribs close together at the lower corner. The form provides stiffness and stability against buckling in both lateral and vertical directions. The bridge deck crossbeams are suspended from hangers which are perpendicular to the arch.

I'm not entirely convinced by the various sections used for the arch members, they seem a little ungainly. I wonder whether all-circular members would have looked better.

The bridge was erected in a single 218t piece by a 600t capacity strut crane. The main contractor is Galliford Try, with Mabey Bridge the fabricator.

Judging from the various images on the Moxon website, the highway bridge is to be complemented by a set of nearby footbridges, part of a separate regeneration scheme, which include a spine beam deck and another arch structure, both pictured below.

Taunton will very quickly become home to a fine set of contemporary structures.

24 March 2011

Bridge competition debris part 25: Millennium Bridge

Not the flippin' Millennium Bridge! Surely there's little more to be said on London's most famous (or infamous, take your pick) modern footbridge?

I think actually there's plenty to be said, not least about its aesthetic merits (vastly over-rated, in my view), about the value of failure in an era of over-reliance on computer modelling, and about the extent to which bridge promoters value star names against design quality.

But I've covered some of that previously, so will leave all that to one side for now, as this is a Bridge Competition Debris™ post, and what I'm interested in is not the bridge that won, but the bridges that didn't.

The Millennium Bridge was one in a series of proposals for a new footbridge linking St Pauls to Bankside across the River Thames. Previous plans had included the Peabody Trust's competition to design a habitable bridge on the same site. In 1996, another competition was held, run by RIBA and promoted by Southwark Council and the Corporation of London.

It's no surprise that the contest for what would be one of the most high-profile new bridges in the world received 226 initial entries.

The entries were reduced to a shortlist of six, as listed below. These were judged by a high-powered panel including the likes of David Sainsbury (chairman of the supermarket chain), Jacques Herzog (architect), Anna Ford (broadcaster) and David Bell (chairman of the Financial Times). Most judges had little real expertise in architecture, and even less in engineering. The token engineering judge was Frank Newby, a great structural engineer but a specialist in buildings, not bridges.

I've provided images of all the entries below, including various draft Arup designs which were altered somewhat in the final version as built. Several of the photos are taken from Deyan Sudjic's book Blade of Light - if anyone is concerned over copyright, let me know and I'll remove them.

Gehry Partners / Richard Serra

Frank Gehry has never been noted as an architect with much sympathy for structural engineering, which he seems to see mainly as a necessary evil, a scaffolding on which to hang crumpled cladding but not to be exposed itself. This design is therefore unsual in his oeuvre, with exposed steel trusses carrying a wide deck and its juttinug promenade / promontory.

The sculptor Richard Serra is better known for sheets of twisted metal plate, so this was a surprising collaboration from both sides.

McDowell + Benedetti

It's interesting to see how this prefigures elements of the same architects' Castleford design, with the expansive timber deck, and the bridge's spine beam hidden below the central raised walkway. However, their design for the Millennium Bridge was more formal, less flowing, with the main span being a cantilever structure pivoting on two massive piers and held down at the end by cables. It's too trapped in its formal simplicity, and it's compromised by the secondary access structures made necessary at each end.

Niels Gimsing / George Rotne

This is easily the most conventional design, and I think it would have been one of the best if built. No histrionics or gimmicks, just a simple, attractive, lightweight suspension bridge, which would have been far more visually transparent than what was actually built.

Studio E (Cezary Bednarski) / Dewhurst Macfarlane / Peter Fink

A truss structure, clad in some kind of translucent skin lending itself to multi-coloured illumination. It's nice - two simple ideas without unnecessary complication.

Ushida Findlay Partnership / Dewhurst Macfarlane

I like the look, but I don't understand the structure. Is that supposed to be a cable underneath? Wouldn't the bottom member be in compression, however? And would a series of pyramids connected by a single longitudinal bottom chord offer sufficient torsional stiffness? Not at this span, surely.

Arup / Foster / Anthony Caro

22 March 2011

Bridge competition debris part 24: Poole Harbour Crossing: Others

Okay, here, finally are all the entries to this 1997 bridge design competition which didn't get at least a Commendation. For previous posts, see the Finalists, Shortlisted, Highly Commended and Commended.

It's a long, long post, so don't expect anything in the way of pithy comment! I've ordered the entries alphabetically, by main named engineer first, and as with previous posts, I'm listing only the main engineering and architectural members of each team - frequently several other firms were involved as cost consultants, lighting specialists etc.

Just try and imagine being on the jury for this contest, faced with 99 entries, not just these images, but supporting documents to read as well!

As always, click on any image for a full size version.

Acer / Ian Ritchie

Acer / Chris Wilkinson Architects

Sufian Al-Shawaf et al / Prof Paul E Regan

Babtie / Nicol Russell

Baikoff & Associates

Robert Benaim / Powell-Williams

KLV Bird, PEP Research & Consultancy

Blake Beston Francois & Associates

Blyth and Blyth Associates / Norrie Toch Studio

Peter Brett Associates / Cheshire Robins Design Group

Peter Brett Associates / Miller Traves

Building Design Partnership


Buro Happold / John Csaky

Buro Happold / University of Bath

NC Buxton

Santiago Calatrava / Dennis Sharp

Campbell Reith Hill IDOM / George West

Cass Hayward / Calzon

Dar Consultants

DHV (UK) & Europe Etudes Gecti / Alain Speilmann Architecte

Dorset Engineering Consultancy

Gifford & Partners

Gifford & Partners / Percy Thomas Partnership

Frank Graham / KHR AS Architects / Cowiconsult

Sir William Halcrow & Partners / Walther Mory Maier / Cezary Bednarski - Studio E

Harris & Sutherland / Jean Muller International / Charles Lavigne

Howard Humphreys & Partners

IOA / Lexiq / Quadric / Soberco

Kara Taylor / Ray Hole

Kumar Associates

Maunsell / Design Research Unit

Maunsell / Percy Thomas Partnership

Michaelayne Architects

Matti Ollila & Co / Harris & Kisjik

Owen Williams

Parkman / Carlos Fernandez Casado / Fairhurst Design Group

Pell Frischmann / Covell Matthews Histon Architects

Pell Frischmann / David Lock Associates

Pell Frischmann / Thorpe Architecture

Rust Consulting / Leonhardt Andra & Partner / Yee Associates

SMP Atelier One / Acer / Apicella Associates

Sir Frederick Snow & Partners / Chapman Cole Partnership

Soliman & Associates

Symonds Travers Morgan / Marks Barfield

Taywood Engineering

S B Tietz & Partners / Graham Herbert Associates

J Tonello / Filippo Broggini & Pascal Amphasx

Anthony Ward Partnership / Davison Associates

Waterman Partnership / Jeffries Lowe Architects

T W Welch / Andrew Waring Associates / Barclay & Phillips

Whitby & Bird

Works International / LaGess McNamara Smith