It will gobble up pollution, glow in the dark and provide a plant-filled oasis: Barcelona’s Sarajevo Bridge promises to be a green revolution

words by Emma Barlow

Most of us are taught from a young age that trees, plants and fauna are absolutely vital for the environment – that they absorb carbon dioxide and breathe out life-giving oxygen. Now an architecture practice in Barcelona has found a way of harnessing this power with a new bridge that will ‘eat’ pollution, as well as being a pleasant and plant-filled space for local people to enjoy.

The structure, known as the Sarajevo Bridge, straddles the Avinguda Meridiana – one of the major roads into Barcelona. The city’s council marked it out as being in need of a redesign and appointed BCQ Arquitectura Barcelona to transform the structure. Toni Casamor, CEO of BCQ explains, ‘It was originally conceived as a bridge for vehicles and now it’s used mainly by people crossing between two neighbourhoods,’ he says. ‘So we want to convert the bridge into a green and public space that people will like to spend time in.’

If the plans go ahead, the new bridge will be coated in a special photocatalyctic concrete that, in simple terms, makes concrete mimic the way leaves on a tree photosynthesise – using energy from the sun to turn polluted air into little more than oxygen and water and keeping the bridge and air around it cleaner. 

“Who knows, maybe one day we can reduce pollution by 20, 30 or 40 per cent?”

This high-tech and potentially revolutionary material works by using titanium dioxide to dissolve smog that has attached itself to the concrete’s surface. This neutralises the pollutants in a process called photocatalysis, turning it into a mixture of oxygen, water, carbon dioxide, nitrate and sulphate, which is then simply washed away by the rain.

‘You can imagine,’ says Casamor. ‘If we used this material on all our road bridges and on the general infrastructure of the city, the air would be less contaminated. Who knows, maybe one day we can reduce pollution by 20, 30 or 40 per cent? Just by using this material over another one.’

sarajevo-bridge-dayview

The environmental considerations don’t stop there either. Casamor and his practice also plan to use verdant plant walls, stunning flowerbeds and pergolas covered in climbing plants to create a new and much-needed green space for the people of Barcelona to use as a place to visit and relax in when they need a break from their urban location. And, of course, these fantastic plants will work alongside the photocatalyctic concrete to improve air quality.

“If you have more green in your public spaces it makes people feel better and it can even have a positive impact on wider society.”

‘Almost everyone in this world likes nature, and if you live in the city you love it all the more because you don’t see so much of it,’ says Casamor. ‘Barcelona is a beautiful city but it is a very densely populated one. If you have more green in your public spaces it makes people feel better and it can even have a positive impact on wider society.’

Incorporating plants into its designs is normal practice for BCQ because in Spain landscaping and architecture are not separate disciplines, so they try to use flowers and foliage whenever they can. ‘We always like to work with natural elements – with vegetation, flowers, plants, trees,’ Casamor says. ‘Of course, there’s a long tradition of using natural elements in public spaces too – whether it’s a large park or a tree-lined avenue – and they are very important.’

The bridge should also run self-sufficiently. Solar panels will generate energy for the bridge’s LED lighting and the pavement will contain beads of a glowing aggregate that will produce self-generating, ambient lighting.  These futuristic beads only need 10 minutes of sunlight to have enough charge to luminesce all night long and BCQ hope these features will help to make the space a safe and welcoming area at night, as well as in the day.

“A green city, interested in the quality
of its human spaces – that’s mainly down to the power of plants.”

So why this bridge? Well, as it is on a major road into the city this bridge goes beyond simply being a connector. ‘It is also a gateway for Barcelona,’ says Casamor, ‘And we need to think of the impression we want to give visitors as they enter the city.’

Barcelona is already one of the European Union’s Green Capitals, with many local people opting to get around the city either on bike or on foot but the new ‘green bridge’ will undoubtedly send out a message.

‘I hope when visitors see the bridge in the future they will like what they see,’ says Casamor, smiling. ‘And that their general image will be of a green city and of a city interested in the quality of its human spaces – and that’s mainly down to the power of plants’.