China's Prefab Construction Methods Go Big

American prefabricated component construction firms have been touting the benefits of this approach for years (also here and here). Assembling large prefabricated parts of a building in factories can make it possible to get better quality, with less waste, at a lower cost, with more worker safety (on site construction is six times more deadly for workers than manufacturing), because the controlled environment is a better one for manufacturing things than an outdoor, constantly changing construction site.  The modular approach also allows a construction company, for example, to build modules for several different floors all at the same time in parallel, while at conventional construction sites, all of the structural elements for one floor of the building must be completed before any of the structural work on the next floor is begun.  All the corner units of a multistory building, for example, might be built at the same time.

At the site, the prefabricated modules can be assembled very quickly, like giant Legos.

This approach is rare in the United States, where most building are stick build from raw construction materials on site, except for some sophisticated ceiling trusses.  A notable exception in Denver's recent building boom was a new apartment building that went up next to the University of Denver light rail station.  It has also been proposed for a nuclear power plant construction plan (from 2005).

But, a project in China, the construction of a 57 story building with 800 apartments and offices for 4,000 workers from 2,700 modules assembled in just three weeks on site (after many months of assembling the modules in the construction company's factory), dramatically illustrates the true revolutionary potential of this approach to construction.  The last 37 stories went up from January 31 to February 17 of 2015.

According to Juliet Jiang, a senior vice president of Broad Sustainable Building, that built the project:

"One hundred percent (of the) parts are factory-made. We don't waste any materials, no one is idle in the workshop or on site. We have very good planning."

Jiang said that the processes employed by the firm are also far more cost effective, environmentally friendly and lead to less disruption in cities during construction.

In contrast, it took almost five years to build London's 37-story Walkie Talkie building which opened in August 2014.