Sky City One: China's Prefab, Record-Setting Skyscraper

There is this reoccurring theme in civil engineering of outdoing other structures. It's as if an architect who suddenly has the financing to build whatever he pleases looks around and says to himself, "Whose is the biggest?" and immediate catches a case of structure envy. So the architect carefully crafts the biggest, most opulent building that construction technology can erect. And then to show off, the architect wants to do it in world record time.

Architects are jealous and selfish lovers professionals. Want an example? Examine Dubai, who wanted to diversify its business away from oil. The way to attract that business? Have the tallest building the world. So they built the 2,722-foot high Burj Khalifa . Never mind the project took five years and cost Dubai $1.5 billion USD, so much money that they later needed a bailout from Abu Dhabi.

In this size contest for world's biggest building, the Burj Khalifa is about to see its successor rise in the province Hunan, China; in the city of Changsha, home to 7 million, will rise Sky City One. When completed in March 2013, the skyscraper will stand at 2,749 ft. Included will be a 1,000 guest hotel, a hospital, five schools, 104 high-speed elevators, 17 helipads, and apartments for 30,000 people.

It's not just the size of the building that is raising eyebrows, however; it's also the rate of construction. The designers plan on erecting Sky City One in just 90 days. Composed of 220 stories, the structure will be completed at a rate of 5 stories a day. The construction cost of Sky City One is not expected to top $700 million USD. The construction company behind the skyscraper, Broad Sustainable Building, has a recent history of extreme construction projects. In 2010 they built a completed 15-story hotel in less than 6 days, and in 2012 they constructed a 30-story hotel in just 15 days.

Furthermore, BSB claims that they are building some of the most environmentally friendly and structurally sound buildings in existence. Sky City One can withstand a 9.0 magnitude earthquake according to tests, primarily because BSB's buildings use less concrete and steel to reduce weight. Six-inch insulated walls and quadruple glazing will contribute to the building's sustainability, which will be constructed from recycled materials. Overall, Sky City One will require one-fifth of the energy needs of a similarly-sized conventional skyscraper. Finally, a unique ventilation system promises air quality 20 times more pure than outdoor air--a needed respite in smoggy China.

BSB is able to accomplish this by essentially replacing construction with manufacturing. Though skilled laborers are need to assemble the building on-site, up to 95% of the building is prefabricated and erected off-site. Completion of a BSB structure is said to resemble the completion of a LEGO or Erector set. BSB founder Zhang Yue believes that the cheapest, most efficient buildings are produced in factories, and this belief has produced 19 buildings in China and one in Mexico.

Of course, anytime an industry is 'revolutionized' by new processes or methods, skeptics and non-believers emerge (again, probably with structure envy). Many expressed doubt that even using prefab techniques a record-setting skyscraper could be built in just three months. Indeed, a BSB spokesperson admitted construction could take seven months, before retracting and promising the company would meet the 90-day threshold. Others critics have taken aim at the building's structural integrity, questioning if Sky City One would be foundationally stable, or if the building's engineers did enough to account for the high lateral forces resulting from wind. Others have questioned emergency support, saying that fire prevention, evacuation and medical emergency procedures have not been thoroughly evaluated.

While these criticisms are valid, they are not even the most crucial considerations for Sky City One's construction. Instead, profitability may be the most debilitating variable of this engineering marvel. China has an extensive history of overbuilding, as governments continue to fund money-losing endeavors to display their prosperity. There are several recent, notable examples. Beijing's National Stadium has been left largely unused since the 2008 Olympics. The largest mall in the world, the New South China Mall in Dongguan, opened in 2005 with 2,350 retail spaces for rent. In a city with 10 million residents, the mall has only leased 1% of its retail space. Kangbashi, a central district in Ordos to provide residence to 1 million Chinese, is home to only about 25,000.

And then there's the craftsmanship. In the instance of BSB's prefabricated building, the unremarkable infrastructure was intended to provide easy franchising and local prefabrication. After construction the building can be customized only to a limited degree. Essentially, the cheap building feels cheap. Personally, I'm not afraid to pay for a more finished, higher quality product, and I expect that any prefabricated building like Sky City One will feel as cheap as it costs, relatively speaking. In the one review a CR4 blogger could find online for the T30 Hotel (BSB's 30-story, 15-day project), the commenter complained of the cramped room sizes, awkward door positioning and uneven floors.

In several years' time, the novelty of Sky City One will have worn off-either because it was succeeded as the world's tallest building (do you remember the Ultima Tower?), or because it's prefab nature limited the on-site adaptability sometimes needed by construction crews and civil engineers. Personally, I'd like to see Sky City One have a successful existence. It could modernize how populations look at buildings and provide low-cost, emission-reducing housing. But I can't help but feel that some personality and workmanship skills will be lost if construction is replaced by manufacture. Though prefabricated building designs are likely to improve, I always hope that there will be a need for laborers who can add character to the buildings we inhabit. I could think of nothing worse than a cityscape that is nothing except interlocking square and rectangles.

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(Image credits: Techjost; 8 Bit Future; Talk Bass; Inhabitat; Webner House; Tree Hugger; TDR Inc.)

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