06 February 2017

Calatrava in Greenwich

Plans have been announced for Santiago Calatrava's second bridge in the UK (the first being 1995's Trinity Footbridge). Yes, there's a whole load of other stuff as well, some yuppie flats and a super-sized greenhouse, but that's not what you read the Happy Pontist for, is it?

Ok, a little context. Calatrava's "Peninsula Place" is just part of a huge £8.4bn redevelopment of London's Greenwich Peninsula, albeit a key part as it includes the gateway underground station. The development is somewhat controversial, largely because of the very small proportion of "affordable" housing which is to be included, following pressure from the developers.

Calatrava's scheme is as grandiose as you would expect. The bridge is intended to link his part of the site, with station and apartment blocks, to the riverside.

It's a cable-stayed structure, so tall that they couldn't even fit all of it into one of the publicity images. In much of Calatrava's recent career the designer seems to have been largely rehashing all his older ideas, while making his designs steadily bigger and steadily more illogical. In line with this principal, he has chosen to stitch together two previous designs to make this new one: Calgary's Peace Bridge, and Valencia's Serreria Bridge.

Frankenstein would have been proud.

The bridge somewhat resembles a giant white snake shedding its skin, rearing up like some kind of super-sized horror-film monstrosity. It's far from clear what it actually spans (only a cycleway is shown in the visualisations), but it seems unlikely that it needs to be this big for functional reasons: like many of Calatrava's recent bridges, its giganticism seems purely symbolic.

The mast is restrained by a single vertical cable, necessitating enormous foundations to counter-balance the main span. (Perhaps it's also symbolic: look, the success of this enterprise is hanging by a thread.)

The curvature of the mast is to some extent structurally rational, as it reduced bending moments and hence should in theory slightly reduce the amount of steelwork required.

The main span is a tubular truss, with metalwork arranged in an intersecting helix, which evokes a futuristic sensibility without actually being structurally sensible in any way: there's a Jane Austen joke in there somewhere, I'm sure.

From the images, it seems as if the mast is on the riverside, which feels the wrong way round to me: the more visually and physically massive part of the bridge should be anchored further inland, I think.

Assuming this entire project doesn't go belly-up following an Brexit or Trump-related economic meltdown, I'm confident this will be a very interesting scheme to watch over the next few years.

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