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|coordinates_display = title
|coordinates_display = title
|status = Under Construction <ref name=autogenerated2>[http://www.china.org.cn/china/2013-07/22/content_29489252.htm China builds 'world's tallest building'- China.org.cn<!-- Bot generated title -->]</ref><ref name=autogenerated3>[http://inequalityreduced.blogspot.com/2013/07/ChangshaskycityWangcheng.html Global Wellbeing: Huilongzhou Village is witnessing a paradigm shift<!-- Bot generated title -->]</ref>
|status = Under Construction <ref name=autogenerated2>[http://www.china.org.cn/china/2013-07/22/content_29489252.htm China builds 'world's tallest building'- China.org.cn<!-- Bot generated title -->]</ref><ref name=autogenerated3>[http://inequalityreduced.blogspot.com/2013/07/ChangshaskycityWangcheng.html Global Wellbeing: Huilongzhou Village is witnessing a paradigm shift<!-- Bot generated title -->]</ref>
|start_date = August 2013
|start_date = July 20, 2013
|est_completion = April 2014
|est_completion = April 2014
|opening =
|opening =

Revision as of 16:21, 25 July 2013

For other uses, see Sky City (Changsha) (disambiguation).
Sky City
天空城市 (Tiānkōng chéngshì)
Artist's conception rendering of Sky City Changsha
Map
General information
StatusUnder Construction [1][2]
TypeMixed-use
Architectural styleSupertall skyscraper
LocationChangsha, Hunan, China
Construction startedJuly 20, 2013
Estimated completionApril 2014
Cost¥5.2 billion
OwnerBroad Sustainable Building
ManagementBroad Sustainable Building
Height838 m (2,749 ft)
Technical details
Structural systemPrefabricated modular
Floor count220 total
Floor area1,215,000 m2 (13,078,151 sq ft)[3]
Lifts/elevators104
Design and construction
DeveloperBroad Sustainable Building
Main contractorChina State Construction Engineering[1]
References
[3][4]

Sky City (Chinese: 天空城市; pinyin: tiānkōng chéngshì), or Sky City One, is an 838 m (2,749 ft) tall skyscraper approved for construction in the city of Changsha, Hunan in south-central China.[5] The prospective builders, Broad Sustainable Building, estimated it would take just 90 days to construct,[6][7] but this is not counting 120 days of prefabrication before on-site work commences; the total schedule is 210 days.[8] If completed, it could become the tallest building in the world.

Broad Sustainable Building, which specializes in making buildings that are sustainable, cost less, use environment friendly materials and can be built in a short amount of time, using techniques like prefabrication, had intended to build a 666 m (2,185 ft) tall skyscraper, but the local government wanted the world's tallest building, hence the current plans.[5][9] The company has constructed 20 buildings in China using the same method and has several franchise partners globally.[10] The Broad Group have previously concentrated on manufacturing large air-conditioners, being among the world leaders in solar air-conditioning, before they shifted to constructing environment-friendly buildings.[11] All employees of the group must follow a manual issued by the company chairman, Zhang Yue, which contains tips on energy-conservation. He also was awarded the Champions of the Earth award by the United Nations in 2011 for his contributions towards the environment.[12]

Building layout

If built as planned and to schedule, Sky City would likely be the tallest building in the world, with 220 floors and a total height of 838 m (2,749 ft). The construction plan calls for it to be built from pre-fabricated units constructed on site in an unprecedentedly short period of 90 days.[6][7] BSB's plan is to assemble 95% of the building in its factory before any excavation takes place at the construction site.[13] The fabrication process is due to take around six months before the actual construction begins.[9][14]

According to the plan, the building's 220 stories will have a hotel accommodating 1000 guests, a hospital, 5 schools, and offices. Of the total space available, nearly 83% will be for residential purposes, housing up to 17,000 people. 5% will be for the hotel housing 1000, while 3% each will be dedicated to schools, hospitals, offices and shops. There will be 10 fire escape routes, which will evacuate everybody in a given floor within 15 minutes; the building will be fire-resistant for up to three hours. It will also have 17 helipads. Sport facilities will include 6 basketball courts, 10 tennis courts. Plans include preserving some green space around the building.

For transportation there will be 104 high-speed elevators installed. Many have critiqued the safety of these potential elevators because they take several minutes to get from bottom to top.[15] The 5000 residential properties will be able to accommodate 17,400 residents. The proposed building will have total floor space of 1.2 million m2(13 million sq ft). The main building will have 1.05 million m2(11 million sq ft) of this area, with a basement of 130,000 m2 (1,400,000 sq ft) and a 3 to 7 floor-high annex of 35,000 m2 (380,000 sq ft).[3] The total capacity of the building will be about 30,000.

The 4-layered glass used for the building's windows will keep the temperature of the building constant between 20 to 27 °C (68 to 81 °F). The air indoors will be specially filtered to be up to 20 times cleaner than the air outside. The lamps used in the building will be made of LEDs, saving energy. It has also been claimed by the builders that they are currently working with architects who worked on the Burj Khalifa.

Structural features

The project will consume 270,000 tons of steel. For its assembly factory, sustainable building technology and independent research and development will be required. The main advantages of the building will be reflected in its earthquake resistance, energy saving, cleanliness, durability, and materials, which consist of recycled building materials, non-aldehyde / non-lead / non-asbestos building materials, etc. The technology at the core of the whole steel structure is modular construction. The building would have 6 inches (15 cm) of insulated walls and quadruple glazing, contributing greatly to energy efficiency.[16] The building will be designed to be resistant to earthquakes of up to 9.0 on the Richter Scale.[17]

Although structural details are not available, outside architects have expressed doubts that a modular design would have the stiffness on lower floors to withstand the wind loads imposed by such a height, without unacceptable amounts of sway,[18] or that the building could be built without high-strength concrete, whose curing time would preclude such a rapid construction rate.[18] Most of the construction and production of materials will take place on site so as to benefit the local economy of Changsha.[19]

A cost estimate of $1500 per square meter[10] of floor space would make Sky City considerably cheaper than the similarly tall Burj Khalifa ($4500 per square meter). The total cost is also considerably less, with the Burj requiring about £940 million ($1500 million) in 5 years, compared to Sky City's £400 million ($625 million) in 90 days.[5][17] Broad Sustainable Group has purchased 67,300 m2 (724,000 sq ft) of land, for a cost of 390 million yuan ($63 million).[15]

Schedule

The project has been delayed in its schedule several times in the past, particularly due to awaiting government approval on starting construction. In October 2012, the group announced that they had received approval from the local government[13] and that construction would begin in November, but announced a new build time of 210 days. This meant completion of the project in June 2013.[20][21] On November 16, 2012, Juliet Jiang, senior vice president of Broad Group, said in an interview that the company will adhere to its previous time table of building five floors a day and completing the building in a 90 day time frame. She also said the building was still waiting for government approval.[10] Later that month the company announced January 2013 as the start for the construction.[22][23]

The final architectural renderings had been completed and the project was to be approved by the central government in early December 2012. Construction is scheduled to begin at some point in 2013 and would take 90 days to complete.[20][24][25]

File:Cscec.png
Logo of CSCEC.

On May 14, 2013, TreeHugger reported that the project has received governmental approval and is set to break ground in June 2013.[26]

On June 17, 2013, Broad Sustainable Building Group Chairman Zhang Yue said that construction will commence in August 2013 with the first four months spent for prefabrication and the next three months for installation onsite. The expected date of completion is March 2014.[8]

On July 20, 2013, Pictures of the groundbreaking ceremony at which Zhang Yue arrived with helicopter along with several dignitaries started to circulate in Chinese websites and Skyscrapercity.[27] These reports provides evidence suggesting China State Construction Engineering is the main contractor and the building is expected to be complete by April and is slated to open in May or June 2014. [2] [28]

On July 25, 2013, it was reported that construction was halted by the authorities, because the building did not receive building permission.[29]

Criticism

The project has come under heavy skepticism due to the nature of its claims, and doubts have been expressed over Broad Group's ability to complete such a project in such a short time. There are also doubts on whether this is an actual project or just a marketing ploy. The head of structures for WSP Middle East (the company behind The Shard in London), Bart Leclercq even jokingly said that he would give up structural engineering if the project did complete on time.[30] Even so, the innovativeness of the group in using a technique like fabrication has been commended by him and others.[31] [32]

While most architects do not particularly contest the possibility of constructing a supertall tower in such a short time frame and with such costs; doubts have been cast by critics over the ability of the Broad Group to achieve such a grand scale project, especially since they have constructed only two[dubious – discuss] buildings as of date, neither of which are over 30 floors. A tower of such height requires stiffness, which in turn would require enormous amounts of concrete and steel, and a huge amount of time for it to settle. The ability of the architects to understand the complexity involved with a project this size has also come under question.[30]

Another factor that seems to have been overlooked in the designs,[citation needed] according to architects,[who?] is the wind factor. A building with such a height and shape will need to deal with large horizontal forces, all the way to the bottom of the tower. Such a wind strategy seems to be absent from the Broad Group's blueprint on the tower.[citation needed] Because of a lack of stiffness, the building would also generate a huge draft and would start to sway due to the wind, making it potentially unstable.[33]

Other concerns by critics have related to the tower's ability to deal with emergencies. In case of a fire, there might not be enough support to douse it nor to evacuate people, as fire rescue crews are generally not equipped to reach such heights. Also, for a person needing emergency treatment, like in a heart attack, the elevators might be too slow to transport them to the hospital in the short amount of time available. Finally, the structure may also cause subsidence in the local geology.[14]

However criticism doesn't include talks or discussion panels - some of experts(e.g. Dr Sang Dae Kim, chairman of the Council on Tall Buildings and Urban Habitat) says that even 2 km towers are possible with modern technology. [34] Plans of company associated with Sky City include also two-kilometre high, 636-floor tower, according to Zhang Yue , CEO, Broad Sustainable Building. [35] Despite the claims the Broad Sustainable Building most known experience include completing prefabricated 30-story hotel in 15 days, where it was completed in a third of the time that would ordinarily be required. Some of experts like Ryan Smith (expert on prefabricated architecture at the University of Utah), said "I've never seen a project go up this fast" about the hotel, and that he thought that prefabrication usually reduce construction time by no more than a half. [36]

References

  1. ^ a b China builds 'world's tallest building'- China.org.cn
  2. ^ a b Global Wellbeing: Huilongzhou Village is witnessing a paradigm shift
  3. ^ a b c "Broad Global | 远大集团". Bsb.broad.com. Retrieved 2012-12-07.
  4. ^ "Broad Global | 远大集团". Bsb.broad.com. Retrieved 2012-12-07.
  5. ^ a b c Chang, Gordon G. (2012-06-17). "Visit China's Changsha, See World's Tallest Building". Forbes.com. Retrieved 2012-06-29.
  6. ^ a b Holloway, James (18 June 2012). "World's tallest building to be built in only 90 days". Gizmag.
  7. ^ a b "Sky City: China plans world's tallest building". CNN. 11 June 2012.
  8. ^ a b "World's tallest tower in China will be ready by March 2014". emirates247.com. 2013-06-17. Retrieved 2013-06-17.
  9. ^ a b Interview of BSB official
  10. ^ a b c "Broad sticks to 90-day completion target | The Malay Mail". Mmail.com.my. 2012-11-16. Retrieved 2012-12-23.
  11. ^ Broad Group in the air-conditioning business
  12. ^ UNEP site on Champion of the Earth
  13. ^ a b Sky City One: Chinese Company To Construct World's Tallest Building Over 90 Days
  14. ^ a b China Daily USA article on Sky city
  15. ^ a b Zhiwei, Feng (November 29, 2012). "Sky City falls short in safety features: Critics". China Daily. Retrieved December 4, 2012.
  16. ^ 220 Story Sky City Close To Breaking Ground
  17. ^ a b Dailymail UK article on the skyscraper
  18. ^ a b Ephgrave, Oliver (2012-08-08). "Can China build its Burj beater in 90 days?". ArabianBusiness.com. Retrieved 2012-11-20. 'If they manage to build this structure in three months then I will give up structural engineering. I will hang my hat and retire. I will be eating humble pie as well.'
  19. ^ Zeveloff, Julie (November 26, 2012). "Why China's Plan To Build The World's Tallest Skyscraper In 90 Days Is 'Madness'". Business Insider. Retrieved December 4, 2012.
  20. ^ a b Coonan, Clifford (2012-11-21). "China to build world's tallest building - in just 90 days - Asia - World". The Independent. Retrieved 2012-12-07.
  21. ^ World's Tallest Skyscraper to Be Built in 210 Days Instead of 90 as Originally Planned
  22. ^ China Plans to Build the World’s Largest Skyscraper in Just 90 Days. Retrieved 2012-11-22.
  23. ^ Deulgaonkar, Parag (November 25, 2012). "Will really Sky City, China, overtake Dubai's Burj Khalifa by March 2013?". Emirates 24/7. Retrieved December 3, 2012.
  24. ^ Blua, Antoine (2012-11-21). "China To Build Tallest Building 'In 90 Days'". Rferl.org. Retrieved 2012-12-07.
  25. ^ "China Plans to Build the World's Tallest Building in Just 90 Days | TIME.com". Newsfeed.time.com. 2012-11-20. Retrieved 2012-12-07.
  26. ^ "One Building, One City: World's tallest prefab, Sky City, is breaking ground in June". treehugger.com. 2013-05-14. Retrieved 2013-05-17.
  27. ^ CHANGSHA | Sky City | 838m | 2749ft | 202 fl | Prep - Page 82 - SkyscraperCity
  28. ^ 六大释疑详解长沙"世界最高楼" 能保9级地震不倒 - 头条新闻 - 湖南在线 - 华声在线
  29. ^ http://blogs.ft.com/beyond-brics/2013/07/25/china-blocks-worlds-tallest-skyscraper-but-not-the-curse/#axzz2Zqc81AlB
  30. ^ a b Ephgrave, Oliver (2012-7-16). "Engineer to retire if China achieves super-quick tower | Design Middle East". Designmena.com. Retrieved 2012-12-23. {{cite web}}: Check date values in: |date= (help)
  31. ^ Ephgrave, Oliver (2012-8-9). "The need for Speed | Design Middle East". Designmena.com. Retrieved 2012-12-23. {{cite web}}: Check date values in: |date= (help)
  32. ^ Wheeler, Carolynne (2012-9-28). "World's tallest tower plan raises eyebrows". The Globe and Mail. Retrieved 2013-1-22. {{cite web}}: Check date values in: |accessdate= and |date= (help)
  33. ^ Ephgrave, Oliver (2012-9-8). "The need for Speed, page 2 | Design Middle East". Designmena.com. Retrieved 2012-12-23. {{cite web}}: Check date values in: |date= (help)
  34. ^ Skyscraper expert says 2km tower is now possible | ConstructionWeekOnline.com
  35. ^ Another world's tallest? Now 2-km high tower is coming up... - Emirates 24/7
  36. ^ China's Broad Sustainable Building completes a 30-story hotel in just 15 days (VIDEO) | GlobalPost

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