I recently visited a handful of bridges built in or near the London Olympic Park. I've covered the park's central bridge last time, and will cover the remainder over the next few posts.
I thought I would be able to say little about Bridge 14, as for such an architecturally interesting bridge, it is almost invisible. It is a pedestrian and cycle bridge which sits alongside a highway bridge and spans over a railway line.
The facts are fairly straightforward: it's 57m long, 6.7m wide, and weighs 203 tonnes. It was designed by Arup and Knight Architects, and built by Morgan Sindall (the contractor only credits their own designer Benaim, and neglects entirely to mention the architect on their website, which is rather poor form).
The weathering steel footbridge girders are 1.8m tall, and double as the parapets. The height, and the solidity of the parapet, are standard requirements of Network Rail for an electrified railway line.
The bridge's most interesting feature is the architectural patterning to the web stiffeners on the external girder. The profile of the stiffeners is varied along the length of the bridge to create a "wave" effect. Anti-climb plates have been included unobtrusively.
Every third stiffener is required structurally to stabilise the girder against buckling, while the others are slightly thinner and entirely architectural, The wave pattern has no structural rationale to it, which I think is a shame, as the web and flange buckling effects are not constant over the span and therefore could perhaps have been used to inspire the stiffener geometry.
Unfortunately, this fascinating girder faces onto the railway, and areas of land inaccessible to the public. It can be seen from a distance, as in my zoomed-in photograph here, but not from close at hand. If you want to see what it looks like, try the Knight Architects website linked below. I am unclear whether surrounding developments will leave this highly sculpted facade permanently invisible to the public!
On the side where the bridge abuts the presumably pre-existing highway bridge, it has the same sculpted girder, except here the girder is hidden within a cage, perhaps to ensure its sheer visual awesomeness doesn't escape?
For a structure with such interesting visual potential, it has been horribly mistreated.