Barcelona is covering a road bridge with concrete that eats pollution

Image: BCQ.

Converting horrible bits of concrete transport infrastructure into green spaces has become a bit of a trend recently. In Hamburg, there's talk of turning a motorway into a park; then there are the dozens of attempts to piggyback on the success of New York's High Line by creating pedestrian walkways and parks.

But one Barcelona bridge is trying something a little different: it's keeping its cars, but introducing a host of sustainable green technologies to make it much, well, nicer.

The Sarajevo bridge is a member of what is surely the grimmest category of urban infrastructure: a road bridge over another road, to the north of the city centre. At the moment, it looks like this:

Under a plan commissioned by the city government and developed by architects BCQ, however, it's due to be transformed. It'll still be a road bridge, but its surface will be paved with pollution-eating "photocatalytic concrete". The pedestrian walkways will be widened so they can be used as plazas, while greenery-covered walls and a canopy will shield users from the noise of the six-lane road below. The bridge will also be entirely self-sufficient, with solar panels on the bridge powering LED lights.

Here's a mock-up of the new bridge as seen from the road below:

And a cross-section:

Click for a larger image.

There's no completion date for this project, which is one of a number of schemes intended to green currently unattractive bits of Barcelona. But it does have the backing of the city government, so unlike so projects that come with cool concept images attached it may actually happen.

We're most fascinated by the smog-sucking concrete, which uses the energy of the sun as it strikes the road to break down pollutants into neutral substances like water, oxygen and nitrates and sulfates; these stick to the surface, and are later washed away by rain.

This probably won't make much of a dent in the pollution produced by the roaring highway below, but every little helps. 

All images: BCQ Architects.

 
 
 
 

This fun map allows you to see what a nuclear detonation would do to any city on Earth

A 1971 nuclear test at Mururoa atoll. Image: Getty.

In 1984, the BBC broadcast Threads, a documentary-style drama in which a young Sheffield couple rush to get married because of an unplanned pregnancy, but never quite get round to it because half way through the film the Soviets drop a nuclear bomb on Sheffield. Jimmy, we assume, is killed in the blast (he just disappears, never to be seen again); Ruth survives, but dies of old age 10 years later, while still in her early 30s, leaving her daughter to find for herself in a post-apocalyptic wasteland.

It’s horrifying. It’s so horrifying I’ve never seen the whole thing, even though it’s an incredibly good film which is freely available online, because I once watched the 10 minutes from the middle of the film which show the bomb actually going off and it genuinely gave me nightmares for a month.

In my mind, I suppose, I’d always imagined that being nuked would be a reasonably clean way to go – a bright light, a rushing noise and then whatever happened next wasn’t your problem. Threads taught me that maybe I had a rose-tinted view of nuclear holocaust.

Anyway. In the event you’d like to check what a nuke would do to the real Sheffield, the helpful NukeMap website has the answer.

It shows that dropping a bomb of the same size as the one the US used on Hiroshima in 1945 – a relatively diddly 15kt – would probably kill around 76,500 people:

Those within the central yellow and red circles would be likely to die instantly, due to fireball or air pressure. In the green circle, the radiation would kill at least half the population over a period of hours, days or weeks. In the grey, the thing most likely to kill you would be the collapse of your house, thanks to the air blast, while those in the outer, orange circle would most likely to get away with third degree burns.

Other than that, it’d be quite a nice day.

“Little boy”, the bomb dropped on Hiroshima, was tiny, by the standards of the bombs out there in the world today, of course – but don’t worry, because NukeMap lets you try bigger bombs on for size, too.

The largest bomb in the US arsenal at present is the B-83 which, weighing in at 1.2Mt, is about 80 times the size of Little Boy. Detonate that, and the map has to zoom out, quite a lot.

That’s an estimated 303,000 dead, around a quarter of the population of South Yorkshire. Another 400,000 are injured.

The biggest bomb of all in this fictional arsenal is the USSRS’s 100Mt Tsar Bomba, which was designed but never tested. (The smaller 50MT variety was tested in 1951.) Here’s what that would do:

Around 1.5m dead; 4.7m injured. Bloody hell.

We don’t have to stick to Sheffield, of course. Here’s what the same bomb would do to London:

(Near universal fatalities in zones 1 & 2. Widespread death as far as St Albans and Sevenoaks. Third degree burns in Brighton and Milton Keynes. Over 5.9m dead; another 6m injured.)

Everyone in this orange circle is definitely dead.

Or New York:

(More than 8m dead; another 6.7m injured. Fatalities effectively universal in Lower Manhattan, Downtown Brooklyn, Williamsburg, and Hoboken.)

Or, since it’s the biggest city in the world, Tokyo:

(Nearly 14m dead. Another 14.5m injured. By way of comparison, the estimated death toll of the Hiroshima bombing was somewhere between 90,000 and 146,000.)

I’m going to stop there. But if you’re feeling morbid, you can drop a bomb of any size on any area of earth, just to see what happens.


And whatever you do though: do not watch Threads. Just trust me on this.

Jonn Elledge is the editor of CityMetric. He is on Twitter as @jonnelledge and also has a Facebook page now for some reason. 

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