Imagine a construction material that's strong enough to carry cars, but as thin as your baby finger. Picture something with enough plasticity to allow bridges to appear like undulating wisps of smoke, and the cladding of apartment towers to resemble cloaks of lace. For too long, steel-and-glass buildings have monopolized our attention. Frankly, I've had my fill of them. It's time to dream again in concrete.
Abandon, for a moment, the old-technology, heavy, thick concrete that dominates and depresses our urban landscape: flat-slab residential towers, chunky bridges, overpasses that are badly cracked and discoloured. Consider a new brand of high-performance concrete that can make us believe again in the poetry of architecture - that might even make us fall in love with infrastructure and what should be the thrill of city-building.
New York's Reiser + Umemoto are at the vanguard of architects working in expressive concrete. The firm's recently completed O-14 residential tower in Dubai uses a superthin concrete shell that allows for light, air and views to filter through its lace-like façade, while providing the building's strength and structural integrity.
The tower, built by Dubai Contracting Company, stands 21 storeys high, without the need for columns or walls. Besides its barrier-free interiors, the building allows for a natural cooling "chimney effect" in the space, nearly a metre deep, between the lacey shell and the main building enclosure. The O-14 is sustainable and stunning. Our planet needs a whole lot more of these.
Producing a lyrical building out of concrete wasn't R + U's first impulse. The pressure to create with glass and steel was great in Dubai, as it is in many other cities, despite the brutal desert sun and the heat sink that glass buildings naturally create.
"We encountered that in Dubai," says Jesse Reiser, who has led his highly experimental studio with partner Nanako Umemoto since 1986, and is also an associate professor of architecture at Princeton University. "Every building was a frame building with a glass-curtain wall - that's the standard - and then you put any kind of stylistic wrapper on it. Our initial schemes for O-14 were heading that way and we reached a crisis point and started working in another direction: What would work in that climate? We ended up with something that was much more sustainable."
In the end, a new-generation "superliquid" concrete was specified by the architects because it can be poured very thin, and is exceptionally malleable, while plasticizing agents make it wonderfully fluid and free of imperfections.
Unlike the rigidity of concrete-slab towers, with one floor poured in exactly the same way as the next, the O-14 allowed for a liberated, responsive form. If the client called with a request, for instance, to enlarge a corner window on a particular floor, the architects could work the new requirement into the design, then contact the engineer with the changes. The process was an iterative back-and-forth between client, architect and engineers. The punched-out aesthetic on the building's cladding looks random but, in fact, it's both logical and free-flowing.
And enchanting. Reiser + Umemoto's design for China's Shenzhen Airport - which sadly has been left on the drawing board - was a symphonic piece of concrete defined by randomized, oblique openings in its roof and walls that make steel-and-glass airports in cities from Toronto to Bangkok seem relatively ho-hum. Their long-span concrete airport - to be the first of its kind in China - would have had light entering like shafts of sunshine cutting through the canopy of a forest.
The architects had collaborated with form workers to develop a system that would have allowed them to set an ultrathin, quick-set concrete between sheets of easy-to-cut Styrofoam rather than between expensive wooden forms. The design was selected by the jury chair to win a recent international competition for the airport, but there was dissent among the jury members. The Shenzhen Airport Authority, meanwhile, preferred a proposed steel structure by Massimiliano Fuksas, competing architects from Rome. In the end, fast, predictable and problem-free prevailed. What a pity for innovation.
Still, Reiser + Umemoto are winning other important design competitions. One of those is the Taipei Music Centre in Taiwan. Scheduled to start construction this winter, it is conceived as the world's first pop-music centre with a cubic hall of fame constructed of new-generation concrete.
Among the most fascinating new brands of concrete is Ductal. Into the traditional concrete recipe - a mixture of sand, cement and water - superplasticizers are introduced at the nano scale, allowing for a thinner, more fluid concrete. Ductal, innovated in France, was used to build the 2010 Olympic cauldron at Whistler; and, before that, to create a series of shell-like overhead canopies for the Shawnessy light-rail transit station in Calgary.
The graceful Peace Bridge in Seoul, South Korea, has a span of 130 metres, but the deck of its footbridge, constructed of Ductal, measures a mere three centimetres thick. It's like a feather floating across the Han River, giving us another reason to believe in the lightness of concrete rather than dreading the way it so often brings a city down.