CCTV Building, A Structural Design Overview
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This document provides an overview of the structural design of the new China Central Television (CCTV) headquarters in Beijing, emphasizing its innovative architectural features and construction challenges. Key elements include its diagrid framing system, seismic stability considerations, and plans for creating an engaging urban environment as part of the 2008 Olympics. Completed by the Office for Metropolitan Architecture (OMA), the building aims to be an iconic structure and has faced numerous engineering challenges to ensure its stability and functionality.
CCTV Building, A Structural Design Overview
- 1. CCTV Headquarters, BeijingA Structural Design OverviewBy Peter M. Bach (August, 2008)
- 2. Before we start…Will it stand by itself?
- 3. Before we start…It can! But the question is: How much effort does it take to make it fall?
- 6. Architecture
- 13. General Project Details BackgroundThe new HQ for China’s CCTV
- 14. Completion in time for Olympics
- 15. Will broadcast the Olympics to the World
- 16. Components:
- 17. CCTV Building (Headquarters & Broadcasting)
- 18. TVCC Wing (Cultural Center, Performing Arts)
- 19. Media Park (Social Gathering Place)
- 20. First of 300 towers to be constructed in Beijing’s CBDGeneral Project Details LocationIn Beijing’s CBD (Third Ring Road)
- 21. East of Forbidden CityGeneral Project Details Admin – Site – History Project Manager: Dongmei Yao
- 22. Partners in Charge: Ole Sheeren & Rem Koolhaas
- 23. Architects: Office for Metropolitan Architecture (OMA)
- 24. Structural Engineers: Ove Arup & Partners
- 25. 10-hectare site
- 26. Two L-Shaped Towers, tallest tower is 230m high
- 27. Total Estimated Construction Cost: €600million
- 28. Will employ 10,000 peopleGeneral Project Details Admin – Site – History (cont.) “…The building is by any conventional definition a Skyscraper…” (UK Telegraph)Comparing Building Heights in AsiaComparing Building Heights in the World
- 29. General Project Details Admin – Site – History (cont.)Towers Lean at 60o angles and “kink” at right angles at the top
- 30. Cantilever overhang starts after 36 floors and is 13 floors high.
- 31. The towers cantilever 75m outwards
- 32. History
- 33. December 2002 - OMA wins design
- 34. March 2003 – Project Start (after review)
- 35. September 2004 – Groundbreaking
- 36. Mid 2007 – Overhang Construction Underway
- 37. Early 2008 – Finalizing ConstructionGeneral Project Details Space Usage
- 38. General Project Details Space Usage (cont.)Yellow = CanteensDark Blue = StudiosGreen = Open StudiosOrange = Lobbies (Tower & Sky)Pale Green = BroadcastingLight Blue = Sports & RecreationRed = VIP AreasLobbies on Ground & Top Floors
- 39. Recreation mainly on bottom
- 40. Elevators in both towers
- 41. Separate Lobby & Elevator for VIPs
- 42. Two Ground Floor Lobbies
- 43. Continuous Loop through Towers
- 44. Studios mainly on the lower FloorsGeneral Project Details Nicknames & Descriptions“Twisted Donut”“The Pants”“Two drunken, upside-down Ls”“Each Tower is a banana, built with a deliberate slight curve…”“Contorted Loop”“Lopsided Colossus”
- 45. Architecture
- 46. ArchitectureWhat do you think “logic” and “beauty” is defined as?
- 47. ArchitectureThe Skyscraper ConceptWhat do all the above buildings have in common?Height!Human Capabilities
- 48. ArchitectureThe CCTV’s ConceptArchitect: Rem Koolhaas
- 49. China willing to try out new ideas
- 50. Everything to do with TV Production is within the CCTV Building (“An inter-connected loop of inter-connected activities”)
- 51. Iconographic Constellation instead of hopeless race for ultimate height
- 52. “…As verticality soars, creativity crashes…”
- 53. “…An Expression of Verticality…”
- 54. Idea should create buildings that will actively engage the cityscapeArchitectureThe Architect’s OpinionCommunity combined as opposed to separate
- 55. Concentrate every program into a single system
- 56. “It is important to encourage different kind of work of engineering as it is with architecture”
- 57. “Experimenting with Engineering liberates imagination and makes other things possible”
- 58. The idea links a bit with communism as is still seen in China
- 59. “There is a natural affinity between the values of architecture and the values of socialism”
- 60. Hopes to spread this new building idea in EuropeArchitectureThe Basic GeometryMobius Strip (continuous loop)
- 62. Diagonal Structural Grid System
- 64. Construction ChallengesWhat kinds of Challenges will this Project face?A lot steel is used Weight Issues (instability)
- 65. Beijing is an Earthquake Prone Area (need seismic stability)
- 66. Every building encounters vertical and lateral loads
- 67. Temperature changes, material deformation
- 69. Shallow foundation not sufficient
- 70. Pore Water present in great amounts
- 71. High Settlement RiskConstruction ChallengesWhat kinds of Challenges will this Project face?Needs to accommodate 10,000 people, heavy equipment High service loads
- 72. Vulnerable to Natural or Man-Made Disasters
- 73. How to design & construct?Performance-based Design Approach
- 75. Diagrid Framing SystemWhat is it?Short for Diagonal Grid System
- 76. Triangulated structure with diagonal support beams
- 77. Similar to a typical moment frame
- 78. Triangles connected at Nodes and Rings intersect the nodes
- 79. Combines the benefits of a hollow tube with a truss
- 80. Loads follow diagonals, gravity and lateral loads can be transferred by the system to the groundSwiss Re, London
- 81. Diagrid Framing SystemWhat is it? (cont.)Can be constructed of either:
- 83. Timber
- 85. Steel is typical because of high tensile and compressive strengths
- 86. Essentially marrying columns, diagonals and bracings into one system
- 87. Not a new technology, used in early aviation and small-scale structuresDiagrid Framing SystemLoad Transfer1.) Vertical Loads2.) Lateral Loads
- 88. Diagrid Framing SystemLoad TransferLoad transfer happens primarily through diagrid
- 89. Internal Cores will transfer minimal amounts of gravity loads
- 90. Floor Slabs do not have to transfer lateral loads
- 91. Less internal columns required = more space
- 92. Floor plates do not have to be of the same shape on each floor
- 93. Continuous and Uninterrupted Load Transfer
- 94. Rings help to resist Buckling Loads transforming whole system into one big tubeDiagrid Framing SystemAdvantages of this SystemStructurally very strong
- 95. Less material required (~20% reduction in steel as opposed to typical moment frame method)
- 96. Aesthetically Pleasing – Blends in together with façade
- 97. Floor plan becomes open and free – more internal space
- 98. Most forms can be created with a triangulated form – architectural freedom
- 99. Self-reliant structure, simple in shapeDiagrid Framing SystemAdvantages of this System (cont.)Simple Construction Technique
- 100. Skyscraper Structural Failure minimized by diagrid construction
- 101. Better ability to redistribute loads than a moment frame (Failure of one portion does not mean complete structural failure)Diagrid Framing SystemDisadvantages of this SystemNot thoroughly explored for skyscraper construction yet
- 103. A diagrid structure will definitely show in the aesthetics, very difficult to hide
- 104. Difficult to create a consistent window design
- 105. Heavy-handed if not executed properly
- 106. Material usage can be very excessive if loads are not highOther Structural Features
- 107. Other Structural FeaturesConnections – Butterfly PlatesCritical Members in the Structural System
- 108. Must ensure a “strong joint-weak member” system
- 109. Must resist maximum probable load from braces with minimum yielding and stress concentration
- 110. Butterfly plates used to assist smooth load transfer
- 111. Finite Element Analysis of ConnectionOther Structural FeaturesConnections – Butterfly Plates
- 112. Other Structural FeaturesFoundation – Piled Raft Total Settlement estimated as
- 113. Differential Settlement kept to 1:500
- 114. Piles are 1.2m diameter and 35m long
- 115. Piled Raft is 7m thick and has a footprint greater than the towers
- 116. Tension piles used away from towers to resist uplift pressuresOther Structural FeaturesLoad Transfer Assistance - TrussesHidden from view for architectural purposes inside
- 117. Link up external columns with internal steel core via pin-joints
- 118. Trusses span the bottom two floors of the overhang, loads above are transferred to these trusses, which subsequently transfer loads to the diagrid system
- 119. Major trusses located at building base (podium) to support the above loadsOther Structural FeaturesLoad Transfer Assistance - Trusses
- 120. Other Structural FeaturesBuilding Internal CoresThree main cores accommodating elevators
- 121. Cores remain vertical despite Tower Slope (shifted against floor plates)
- 122. One core dedicated to “Grandness” (Administrative), the other to “Newness” (News & Technology)Miscellaneous Topics
- 124. Miscellaneous TopicsSeismic Stability Design ApproachCCTV Performance-based Design for Seismic Stability well outside National Building Codes
- 125. Analysis for different seismic events
- 126. Level 1: Frequent Earthquake No structural damage
- 127. Level 2: Intermediate Earthquake Repairable Structural Damage
- 128. Level 3: Rare Earthquake Severe Structural Damage permitted, must not collapseMiscellaneous TopicsSeismic Stability Design ApproachOther Research shows test results depicting Overhang vertical displacement with time during an Earthquake
- 129. Tests also show that some braces go into plastic buckling during the Earthquake Dissipate seismic energy (GOOD)Maximum downward displacement = 700mm
- 130. Miscellaneous TopicsDealing with WindWind Tunnel Experiments had to be carried out to assess the severity of Wind Loads
- 131. Building strength against a 100-year Wind was assessed
- 132. Method: Dynamic Analysis using High-Frequency Pressure Integration Method
- 133. 285 Pressure Taps installed on 1:500 Scale Model
- 134. North and West Winds Critical
- 135. Southwest Wind worst for Vertical LoadsMiscellaneous TopicsEmergency ScenariosIn the event of a fire or a major disaster (natural or man-made) that causes major structural damage, what are the possible escape routes and how long will it take?Miscellaneous TopicsEmergency Scenarios (cont.)Numerous Escape Routes
- 136. Looped Structure an Advantage
- 137. Reduced Escape Time
- 138. Better SafetyThe Other Buildings
- 139. The Other BuildingsThe TVCC BuildingHotels, Theaters, Cultural Center for Performing ArtsThe Other BuildingsService Building & Media ParkService Building: Energy Center, Guards Dormitories, Major Broadcasting Vehicle Garages, Fire Control Center
- 140. Media Park: Social Gathering place, filming optionsConstruction ProgressLatest Pictures of the BuildingDated June 2008
- 141. Conclusion
- 142. ConclusionBuilding is to become an icon of Beijing’s Cityscape once completed and will play an important role for the 2008 Olympics
- 143. Architecture looks at iconography rather than the race for height – engineering creativity is better than height
- 144. Many structural challenges to overcome in realizing the project Performance-based design needed
- 145. Diagrid System, Butterfly Plates, Piled Raft Foundations, Load Transfer Trusses all deemed good solutions
- 146. Seismic and Wind Stability ensured through rigorous analysis
- 147. Emergency Escape Routes are effective
- 148. Other buildings on-site serve unique functionsReferences[1] Carroll, C., Xiaonian, D., Gibbons, C., Lawson, R., Lee, A., Luong, A., Megowan, R., Pope, C., (2006), “China Central Television Headquarters – Structural Design”, Steel Structures 6[2] CB Richard Ellis, (2007), “The CCTV Tower: Central Icon of Post-Urban Beijing?”, CBRE Research – Asia 2007 Issue 1[3] “CCTV Address”, China Academic Journal Electronic Publishing House, http://www.ckni.net, Last Accessed 25th May 2008[4] “CCTV by OMA”, A+U Architecture & Urbanism July 2005 Special Issue, Tokyo, Japan[5] “China Central Television (CCTV) Headquarters”, Design Build Network, http://www.designbuild-network.com/projects/cctv/, Last Accessed 25th May 2008[6] Koolhaas, R., (2004), “Beijing Manifesto”, Wired Issue 8 2004[7] Lee, S., “Nonlinear Dynamic Earthquake Analysis of Skyscrapers”, CTBUH 8th World Congress, Dubai 3-5 March 2008[8] McCain, I., “DiaGrid: Structural Efficiency & Increasing Popularity”, http:// daapspace4.daap.uc.edu/~larsongr/Larsonline/SkyCaseStu_files/Diagrid.pdf, Last accessed 25th May 2008[9] “OMA – New Head Quarters – Central Chinese Television”, arcSpace.com, http://www.arcspace.com/architects/koolhaas/chinese_television/, Last Accessed 25th May 2008[10] Telegraph.co.uk, “2008 Olympics: New Towers for a New Superpower”, UK Telegraph, http://www.telegraph.co.uk/arts/main.jhtml?xml=/arts/2007/12/29/babeijing129.xml, Last Accessed 25th May 2008[11] Telegraph.co.uk, “China’s ambitious building passes key test”, UK Telegraph, http://www.telegraph.co.uk/news/uknews/1572347/China%27s-ambitious-building-passes-key-test.html, Last Accessed 25th May 2008[12] Xie, J. , To, A., “Design-Oriented Wind Engineering Studies New China Central Television Headquarters”, Technotes Issue No. 26, RWDI Consulting Engineers & Scientists
- 149. Questions
Editor's Notes
- #10: OMA is Rotterdam based
- #12: Towers constructed at opposite diagonal corners of a 160m x 160m footprint, linked by an L-shaped podiumCo-joined at the top by an L-shaped bridge opposite the podiumTower footprints are 40mx60m and 52mx42mThin concrete cores support internal floors
- #19: Rem Koolhaas founded OMA
- #20: This is the current typology of a skyscraper, there’s a core and a group of people here and people there and you see each of them isolated, there you can do two things: Combine all cores to make the communities into one or distribute the cores without dividing the communities
- #21: This is the current typology of a skyscraper, there’s a core and a group of people here and people there and you see each of them isolated, there you can do two things: Combine all cores to make the communities into one or distribute the cores without dividing the communities