Financial Post – Prefabrication has long been studied but not widely implemented in commercial buildings, says Steven Moore, professor of sustainable design at the University of Texas.
But despite an image of assembly-line flimsiness, “prefabrication can contribute to higher-quality construction, which in turn improves efficiency with less energy consumption,” Moore said.
“What I find interesting about what they’re doing is that they’re now becoming almost like automobile makers,” by adapting prefab techniques to construction, Moore said in an interview.
Broad’s use of non-electric chillers powered by natural gas and waste heat is a significant step for greater energy efficiency.
“It’s very easy to learn the construction — all the workers need to do is fasten the bolts,” said Liu Zhijian, a 23-year-old site worker from the nearby city of Loudi.
“There’s no welding, no dust, no water,” he said. “It’s not at all like traditional construction, which is all about bricks and concrete.”
The process keeps costs down as well, about 4,000 yuan (US$635) per square metre. At 4,500 square metres, the cafeteria comes to 18 million yuan (US$2.8-million). Broad says that is up to 30% cheaper than conventional buildings.
A combination photo shows the progress (from top to bottom) of constructing the three-storey D3 cafeteria by the Broad Group in Yueyang, Hunan province between April 24 to May 7, 2012.
Workers prefabricate flat modules at two factories in Yueyang, about 90 minutes north of the provincial capital of Changsha.
The tops of the modules, the largest of which measure about 4 x 15 metres, are covered with flooring. On the undersides, forming the ceiling of the floor below, air and water pipes are pre-installed, to be connected once the modules are in place.
BSB estimates it produces 90% of its buildings in the plants.
The process also leaves little trash behind.
“We have only 1% of construction waste at building sites,” said Shang Dayong, a worker from Ningxia province who came to learn the quick-build process to teach others back home.
“With these buildings, we can tear them down and rebuild them somewhere else.”
Ningxia is also vulnerable to earthquakes, so BSB buildings have extra appeal, Shang said. BSB claims its structures can withstand earthquakes up to magnitude 9.0 — similar to the devastating quake that hit northeast Japan last year.
Zhang has bigger plans. He has his eyes on a 50-storey quick-build structure in the near future and is seeking investors for a 220-storey behemoth in Yueyang.
Broad Group Has Plans for a 666 meter tall skyscraper
A Chinese company developed new factory prebuilt construction that can make a 15 story building in 6 days plans to build the second tallest building in the world over 6 months. 93% of the construction work is done in the factory vs at most 40% in western countries.
The Changsha Broad Air Conditioning Company has unveiled designs for the 200-storey Sky City tower, a sustainable mixed use project. At 666 meters tall, the building will house 1.2 million square meters of space for residential apartments, retail, offices, restaurants, schools and a myriad of other facilities. The building will be manufactured in a factory and assembled on the construction site. Additionally, the tower will have the capacity for 70,000 to 110,000 residents.
They are trimming their costs to 7,000 yuan to 8,000 yuan per square meter. The company then adds its profit margin and sells its properties for around 10,000 yuan per sq m – or about half the price of properties in Shanghai outside the city center. This would convert to a 660 square foot unit costing about US$100,000. The whole building is 1.2 million square meters so this project will cost about US$1.25 to 1.46 billion and will sell for $1.83 billion. Numbeo has Shanghai cost of living and Shanghai apartment prices are currently three to six times as high to buy as these apartments would be
Comfort of Skycity
• 100% fresh air, no mixed with return air, eliminate infection. 3-stage filtered fresh air , 99% nano-particulates be filtered. Indoor air is 20-100 times cleaner than outdoor air. Central vacuuming system keeps indoor air quality.
• Space blocks and all rooms remain at 20~27 ℃ all year round, glass wall enable
sunshine lighting up the streets.
• The clear height of residences and office is 2.8m, the clear height of space blocks are 5.6m, 9m, 12m respectively.
• Four 4meter wide streets start from the ground to the floor 121 at 400m, the total length of street is 12km, shops, agriculture markets, handcraft shops, restaurants, amusement parks, sports centers, natatorium, cinemas, opera houses, museums, libraries, training centers, schools, kindergartens, clinics, banks, police stations, etc. on both sides of street, same as city downtown. Botanical garden, natural parks, fishponds, waterfalls, sand beach can be found in some floors, same as the suburban.
• 16 large observation elevators and 31 high-speed elevators can serve 30,000 people every hour.
• Level 9 earthquake resistance, scale model will be tested by national authorized institution.
• BROAD unique technologies “diagonal bracing, light weight, factory-made” ensure the
highest earthquake resistance level with minimum materials.
• Trapezoidal construction structure corresponds the law of mechanics, which can withstand earthquake and storm.
• Sky gardens locate on floor 71, 121, 156, 176 and 191(12,000m2 in total), also function as the helipads, which are able to evacuate tens of thousand people during fire emergency, provide extra fire protection than conventional skyscrapers.
• 150mm exterior insulated walls, triple-paned windows, exterior solar shading, interior window insulation and heat recovery fresh air, 80% more energy efficient than conventional buildings.
• Adopting “distributed energy system”, turbines provide power independently, exhaust from turbines is the source for cooling, heating and sanitary hot water. 50% more energy efficient than the power grid.
• Indoor HVAC is controlled by occupancy sensor, fan speed will be automatically adjusted to the lowest load when people left.
• Elevator generates electricity when ascending unload and descending full load, also choose the floor outside the elevator, and other electricity saving methods can save 75% more electricity than conventional elevator.
• LED lamp, 90% more energy efficient than incandescent lamp and 50% more energy efficient than fluorescent lamp.
• Separated drainage system, rain water is used for plant irrigation, bathing water will be directly drained after settled, bathroom sewage and kitchen waste go to biogas tank, biogas is used as fuel for air conditioning, and solid wastes become organic fertilizers.
• Annual energy conservation 60,000 ton oil equivalent
• Saving 600,000 ton construction materials
• Saving 1.4 sq. kilometers land (volume ratio 50)
• On-site construction waste is less than 1% of the total weight
• Zero raise dust on-site
• Zero water consumption on-site
• Recycle processes of living garbage from the building
• All steel structure, reuse after abandoned
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Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
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