The company plans to build the 220-story Sky City tower in Changsha City using modular construction technology developed by its Broad Sustainable Building (BSB) Company. Construction is set to start in November 2012, with completion expected by January 2013.
That would mean an eye-popping construction speed of five stories per day.
By comparison, the current tallest building in the world — the 163-story Burj Khalifa in the United Arab Emirates — took around six years to complete.
Broad has already shown it can build buildings quickly. It recently finished construction of a 30-story hotel, also in Changsha, in 15 days. It’s also completed a 15-story hotel in one week and a six-story pavilion in one day.
The secret, according to Broad, is modular construction where 93 percent of a building is finished in a factory before being shipped to the construction site:
“The most revolutionary element about BSB is its construction mode: a 3.9 × 15.6m ‘main board’ including flooring and ceiling, embedded shafts of ventilation, water supply & drainage, electricity and lighting. All needed pillars, diagonal bracings, doors, windows, walls and even sanitary & kitchen wares for the room installation are placed on main board for factory shipment. One truck can carry 120m2 main boards and then deliver them to the construction site to be hoisted in installation place. What all workers need to do is just screwing bolts, painting … Such a high-efficiency construction mode makes on-site installation only account for 7% of the total construction hours. Therefore, BSB can be 93% factory-made, whereas the current world’s highest is only 40%.”
That approach is also material-efficient, reducing construction waste while resulting in structures with low energy footprints and high earthquake resistances, according to Broad.
“We do not intend to erect a landmark,” Broad notes about the Sky City project, “but to develop and extensively build, a practical building with medium cost and ultra-low energy consumption which will reciprocally shape the future urban life style.”