57-floor building goes up in 19 days

Editor's note: In recent years, China has witnessed the largest growth in building construction in the world, around 2 billion square meters of floor space added annually, with the associated huge amount of waste generated during the building work. Prefabrication may offer a solution to the waste problem, as well as creating green buildings.

Changsha company Broad Sustainable Building has built a 57-floor building in only 19 days in Februday, handling the construction as if working with Lego blocks, as many netizens commented after seeing an online video of the work.

Mini Sky City was built by 1,200 workers working around the clock in Changsha, Hunan province. The 200-meter structure contains 800 homes and working spaces for 4,000 people, said Xiao Changgeng, the company's manager. All that remains is the interior decoration.

"It could be built quickly because the steel structure was made of prefabricated parts, and 95 percent of the process took place in plants in advance," Xiao said.

The building is more earthquake-resistant than other buildings and also more energy efficient. Moreover, it is 80 percent more energy efficient than a regular building with steel and concrete, cutting carbon dioxide emission by 12,000 metric tons annually, he said.

Prefabricated steel structure buildings have been widely adopted for commercial buildings in China for their better energy efficiency and shorter construction period, said Liu Dongwei, chief architect of the China Institute of Building Standard Design & Research at the Ministry of Housing and Urban-Rural Development.

A steel building has a metal structure for internal support and exterior cladding, as opposed to regular steel and concrete buildings, Liu said.

"They could be a good solution to promote green construction, considering the huge amount of waste produced in the whole process of building," he said.