"The World of Footbridges: From the Utilitarian to the Spectacular"

I've recently received a copy of "The World of Footbridges" by Klaus Idelberger (Ernst and Sohn, ISBN 978-3-433-02943-5, 192 pp, 2011) [amazon.co.uk] (also available in a cheaper German edition).

The book presents a collection of modern pedestrian and cycle bridges, all of steel construction, sourced from Europe and Asia, although by far the largest number are in Germany.

The book is aimed very much at practicing bridge design engineers. Each bridge is given a one or two-page spread, with CAD or simplified dimensional drawings, photographs, and detailed descriptions of the structure. A typical page is shown below (click on it for a larger version).

These pages include detailed facts regarding structural members, protective treatment, cable materials etc - the sort of thing which makes the book of considerably less interest to non-engineering designers such as architects, or indeed to non-specialists. The text is clear and well translated throughout, and not without a sense of humour, as when the author notes how the decking on a suspension footbridge near Lavertezzo, Switzerland, was sized to suit the private owner's dog. The author is also not afraid to criticise when appropriate, drawing attention to occasional poor details such as climbable balustrades.

The photographs are mostly in colour, although they are sometimes a little too small to properly appreciate the more beautiful structures. However, this is not a coffee table tome devoted only to the spectacular and aesthetically sublime. Many of the bridges are functional rather than beautiful, and some are frankly ugly, often the result of an attempt to do something offbeat or unusual. This isn't a bad thing, indeed it's great to see a very different range of bridges from what is more commonly portrayed.

"The World of Footbridges" is organised by structural type: suspension bridges; cable and bar-stayed bridges; girder bridges; arch bridges; and enclosed skywalks. This throws some interesting bridges against each other, particularly in the final section, which is perhaps the one I found most interesting - enclosed bridges are always difficult to design well.

The book features a number of bridges which should be well known: SBP's Inner Harbour Bridge at Duisburg, and their Gahlensche Strasse bridge at Bochum; the Miho Museum Bridge; the Dreilanderbrucke; and the Corporation Street footbridge.

In one or two cases, the books strays beyond the factual. Although the author personally visited most of the bridges, he clearly didn't go to the Royal Victoria Dock footbridge, which he states has a suspended transporter pod (actually never installed), nor the South Quay Footbridge, which he describes as having two masts (one was removed some time ago). These errors didn't detract much from the rest of the book for me, but it may be worth treating some of the other "facts" with a pinch of salt.

"The World of Footbridges" introduced me to several remarkable structures that I hadn't previously encountered, such as the Regnitzsteg in Bamberg, with its intriguing cable net system (pictured); Stefan Polónyi's Doppelbogenbrücke in Gelsenkirchen (pictured on the book cover - despite appearances, the two arches are parallel and equal in span and height); and a number of excellent, ultra-economic suspension spans in Switzerland (see one example).

Even amongst the more straightforward structures, there are several examples of good detailing to be seen. The bridge may also help draw attention to practices that are simply local customs rather than based on real merit. For example, many of the bridges featured are galvanised but not painted, which is not what would normally be done in the UK, where normally bridges are painted without being galvanised, except for parapets, which are both. Whether examples from elsewhere can encourage procurement authorities to make exceptions to their traditional requirements must remain doubtful, however.

A similar point that I noted is a number of European footbridges over railways which take what, in the UK, would be regarded as an unacceptable approach to the parapet design. In Britain, tall (1.5m or 1.8m) parapets which are solid without gaps (normally in steel plate), are invariably required, supposedly to reduce vandalism (although what is to stop people lobbing bricks over a tall parapet is anyone's guess). The solidity is supposedly there to stop people trailing cables down onto overhead wires or onto the track. "The World of Footbridges" has several bridges with perforated or mesh parapet above a railway, and again, it's depressing to be reminded of the UK's rulebound, jobsworth tendency.

I wouldn't say this is a book which is going to be a huge source of inspiration to designers, in the way that some of its coffee-table competitors may be. It's more of a reference source for bridge forms and details which are interesting rather than aspirational. I certainly enjoyed seeing designs I'd not otherwise be exposed to, and stored away several ideas to consider in my own work in the future.