China's impressive building credentials have been in the news regularly over the past few years, particularly those in evidence at the Shanghai World Expo and Beijing Olympic Games. The most recent example of the striking capability of the Chinese building industry took place in Changsha, Hunan province a few months ago. China's Broad Group showcased their rapid building technology by constructing the 15-story Ark Hotel in less than six days. Using a team of 200 workers the structural framework was erected in just 46.5 hours and the external cladding and internal non-structural surfaces were completed in another 90 hours.
The Ark Hotel used one sixth the material of an equivalent sized building with a cost saving of 20% while still being able to withstand a 9.0 magnitude earthquake. In addition the building uses several technologies to result in energy efficiency five times that of comparable buildings. This includes triple pane windows, external solar shades, 6 inches of thermal insulation, heat recovery ventilation, and LED lighting systems. The plan is to construct 15 similar structures in China and 30 more in other countries.
To be fair, the foundations and other below-ground construction were completed prior to starting the clock and the construction system makes significant use of prefabricated components produced in a dedicated factory, so the "time cost" of these aspects of the process have been left out of the six day figure. But even taking those caveats into account the speed from ground level to 15 stories is certainly impressive as shown in the video below.
The Broad Group and its rapid building technology first came to international attention when they constructed a pavilion for Shanghai's World Expo in one day! The following video shows that remarkable feat and also showcases some of the innovations integral to the building approach.
While it is undoubtedly the speed of construction that will bring this building technology to the attention of developers worldwide it is the environmental aspects that are, I believe, most impressive. Energy efficiency, reduction in material use and building waste minimization are all of paramount importance if we are to build a sustainable human environment into the future.
Dr.A.Jagadeesh Nellore(AP),India
Just like the Liberty ships os WW2:
http://www.liberty-ship.com/html/yards/kaiserperm2.html
The fastest ones were built special to make a record, but they did refine techniques to go from 50 days in drydock to less than 19 days each by the end of the war.