Steel Structure 57-storey in 19 days Case Study: Mini Sky City, Changsha, Hunan, China

Mini Sky City was built by 1,200 workers working around the clock in Changsha, Hunan province.

The challenge has been met using a total of 10,345 tonnes of beams to build the core of the J57 building also known as Mini Sky City.

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

Broad Sustainable Building, a prefab construction firm, put up the rectangular, glass and steel Mini Sky City in the Hunan provincial capital of Changsha, assembling three floors a day using a modular method.

Broad Sustainable Building spent four and a half months fabricating the building’s 2,736 modules before construction began. The first 20 floors were completed the previous year and the remaining 37 were built from 31 January to 17 February of 2015.

The skyscraper is built with factory-produced, LEGO®-like blocks, using a modular construction technique. The process is based on a factory-fabricated steel structure system and on-site installation, using flanges and high strength bolts to join the construction members.

The structure is one of the tallest modular buildings in the world.

It also incorporates integrated, installable floor slabs, light wallboard, and other prefabricated materials.

The rectangular, glass and steel building has 19 atriums, 800 apartments and office space for 4,000 people.

It worked on Mini Sky City in two bursts interrupted by bad weather. Its time-lapse video of the rapid build has become popular on Chinese video sharing sites since it was first uploaded to YouTube.

With the traditional method they have to build a skyscraper brick by brick, but with this method they just need to assemble the blocks.

Modular methods have been used for high-rise apartment blocks elsewhere, including in Britain and the US. Some critics say the method could lead to cityscapes with overly uniform architecture.

But this method is worth developing because it could become a safe and reliable way to build skyscrapers quickly.

Mini Sky City has 19 atriums, 800 apartments and office space for 4,000 people. The structure is safe and can withstand earthquakes.

According to BSB architect Xian Min Zhang, the use of modules in the construction of J57 reduced the use of concrete by 15,000 trucks, which he says almost eliminated the release of dust in the air, an important advantage in pollution-ridden China.

This project used parts assembled at plants for high energy efficiency and environmental friendliness

In fact, BSB’s focus is on green construction, and one of the convincing arguments is that all the beams are made of scrap.