The Chinese construction company that had vowed to build the world’s tallest building in just three months – at a fraction of the cost of comparable skyscrapers – has admitted that it is behind schedule.
Broad Sustainable Building (BSB) announced its plans for the 220-storey J220 skyscraper in Changsha, Hunan Province in June.
The company claimed that the building, now named Sky City, would top out at a height of 838m — 10m higher than the Burj Khalifa — in 90 days and cost $628m to construct.
The construction schedule has now been revised to seven months, or 210 days – far longer than the period the company originally projected but still an astonishing speed when compared to conventional high-rise construction. In comparison, the Burj Khalifa took five years to build.
Following an interview with BSB founder Zhang Yue in September, Wired reporter Lauren Hilgers said:
“It’s hard to say for sure that the 1.5M-square-metre plan isn’t entirely a publicity stunt. But Zhang has hired some of the engineers who worked on the Burj Khalifa, and Broad has created two large models. The foundations are scheduled to be laid in November at a site in Hunan; and, if everything goes well, the building will be complete in March 2013.”
The key to the rapid low-cost proposal is BSB’s proprietary prefabrication technique, a method by which BSB eventually hopes to sell its prototype skyscrapers around the world.
Sky City will be a mixed-use building, with luxury apartments, low-income housing, and space for businesses and retail units, according to the company.
It will also be earthquake-resistant and have 31 high-speed elevators to take visitors to upper-level observation decks.
BSB has already built 16 structures in China and demonstrated its proficiency for high-speed builds on several projects. Most recently, the company gained worldwide attention by constructing a 30-storey hotel in just 15 days, recording it in timelapse.
The 30-storey BSB hotel was tested by the China Academy of Building Research and found to be able to resist a 9.0 magnitude earthquake, and was subsequently recommended in an United Nations Environment Program report on the rebuilding of Sichuan after its catastrophic earthquake in 2008.
The buildings is also five time more energy-efficient than a traditionally-built scheme and was delivered at a cost of $1,000 per m2 compared with $1,400 per m2 for conventional high-rise construction in China.