CCTV Building, A Structural Design Overview


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The CCTV building is one of the several big Beijing Olympic projects, which houses the headquarters for the Chinese Central Television Network. Its design shows unique style, but great structural engineering challenges to overcome. The following presentation provides an overview of how these challenges were overcome. (Presented at Monash University, Department of Civil Engineering, August 2008).

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  • OMA is Rotterdam based
  • 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
  • Rem Koolhaas founded OMA
  • 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
  • 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
  • CCTV Building, A Structural Design Overview

    1. 1. CCTV Headquarters, Beijing<br />A Structural Design Overview<br />By Peter M. Bach (August, 2008)<br />
    2. 2. Before we start…<br />Will it stand by itself?<br />
    3. 3. Before we start…<br />It can! But the question is: How much effort does it take to make it fall?<br />
    4. 4. Before we start…<br />THIS?!<br />
    5. 5. Topics<br /><ul><li>General Project Details
    6. 6. Architecture
    7. 7. Construction Challenges
    8. 8. Diagrid Framing System
    9. 9. Other Structural Features
    10. 10. Miscellaneous Topics
    11. 11. The Other Buildings
    12. 12. Conclusion</li></li></ul><li>General Project Details<br />
    13. 13. General Project Details <br />Background<br /><ul><li>The new HQ for China’s CCTV
    14. 14. Completion in time for Olympics
    15. 15. Will broadcast the Olympics to the World
    16. 16. Components:
    17. 17. CCTV Building (Headquarters & Broadcasting)
    18. 18. TVCC Wing (Cultural Center, Performing Arts)
    19. 19. Media Park (Social Gathering Place)
    20. 20. First of 300 towers to be constructed in Beijing’s CBD</li></li></ul><li>General Project Details <br />Location<br /><ul><li>In Beijing’s CBD (Third Ring Road)
    21. 21. East of Forbidden City</li></li></ul><li>General Project Details <br />Admin – Site – History <br /><ul><li>Project Manager: Dongmei Yao
    22. 22. Partners in Charge: Ole Sheeren & Rem Koolhaas
    23. 23. Architects: Office for Metropolitan Architecture (OMA)
    24. 24. Structural Engineers: Ove Arup & Partners
    25. 25. 10-hectare site
    26. 26. Two L-Shaped Towers, tallest tower is 230m high
    27. 27. Total Estimated Construction Cost: €600million
    28. 28. Will employ 10,000 people</li></li></ul><li>General Project Details <br />Admin – Site – History (cont.) <br />“…The building is by any conventional definition a Skyscraper…” <br />(UK Telegraph)<br />Comparing Building Heights in Asia<br />Comparing Building Heights in the World<br />
    29. 29. General Project Details <br />Admin – Site – History (cont.)<br /><ul><li>Towers Lean at 60o angles and “kink” at right angles at the top
    30. 30. Cantilever overhang starts after 36 floors and is 13 floors high.
    31. 31. The towers cantilever 75m outwards
    32. 32. History
    33. 33. December 2002 - OMA wins design
    34. 34. March 2003 – Project Start (after review)
    35. 35. September 2004 – Groundbreaking
    36. 36. Mid 2007 – Overhang Construction Underway
    37. 37. Early 2008 – Finalizing Construction</li></li></ul><li>General Project Details <br />Space Usage<br />
    38. 38. General Project Details <br />Space Usage (cont.)<br />Yellow = Canteens<br />Dark Blue = Studios<br />Green = Open Studios<br />Orange = Lobbies (Tower & Sky)<br />Pale Green = Broadcasting<br />Light Blue = Sports & Recreation<br />Red = VIP Areas<br /><ul><li>Lobbies on Ground & Top Floors
    39. 39. Recreation mainly on bottom
    40. 40. Elevators in both towers
    41. 41. Separate Lobby & Elevator for VIPs
    42. 42. Two Ground Floor Lobbies
    43. 43. Continuous Loop through Towers
    44. 44. Studios mainly on the lower Floors</li></li></ul><li>General Project Details <br />Nicknames & Descriptions<br />“Twisted Donut”<br />“The Pants”<br />“Two drunken, upside-down Ls”<br />“Each Tower is a banana, built with a deliberate slight curve…”<br />“Contorted Loop”<br />“Lopsided Colossus”<br />
    45. 45. Architecture<br />
    46. 46. Architecture<br />What do you think “logic” and “beauty” is defined as?<br />
    47. 47. Architecture<br />The Skyscraper Concept<br />What do all the above buildings have in common?<br />Height!<br />Human Capabilities<br />
    48. 48. Architecture<br />The CCTV’s Concept<br /><ul><li>Architect: Rem Koolhaas
    49. 49. China willing to try out new ideas
    50. 50. Everything to do with TV Production is within the CCTV Building (“An inter-connected loop of inter-connected activities”)
    51. 51. Iconographic Constellation instead of hopeless race for ultimate height
    52. 52. “…As verticality soars, creativity crashes…”
    53. 53. “…An Expression of Verticality…”
    54. 54. Idea should create buildings that will actively engage the cityscape</li></li></ul><li>Architecture<br />The Architect’s Opinion<br /><ul><li>Community combined as opposed to separate
    55. 55. Concentrate every program into a single system
    56. 56. “It is important to encourage different kind of work of engineering as it is with architecture”
    57. 57. “Experimenting with Engineering liberates imagination and makes other things possible”
    58. 58. The idea links a bit with communism as is still seen in China
    59. 59. “There is a natural affinity between the values of architecture and the values of socialism”
    60. 60. Hopes to spread this new building idea in Europe</li></li></ul><li>Architecture<br />The Basic Geometry<br /><ul><li>Mobius Strip (continuous loop)
    61. 61. Cantilever Overhang
    62. 62. Diagonal Structural Grid System
    63. 63. L-Shaped</li></li></ul><li>Construction Challenges<br />
    64. 64. Construction Challenges<br />What kinds of Challenges will this Project face?<br /><ul><li>A lot steel is used  Weight Issues (instability)
    65. 65. Beijing is an Earthquake Prone Area (need seismic stability)
    66. 66. Every building encounters vertical and lateral loads
    67. 67. Temperature changes, material deformation
    68. 68. Subsoil Conditions:
    69. 69. Shallow foundation not sufficient
    70. 70. Pore Water present in great amounts
    71. 71. High Settlement Risk</li></li></ul><li>Construction Challenges<br />What kinds of Challenges will this Project face?<br /><ul><li>Needs to accommodate 10,000 people, heavy equipment  High service loads
    72. 72. Vulnerable to Natural or Man-Made Disasters
    73. 73. How to design & construct?</li></ul>Performance-based <br />Design Approach<br />
    74. 74. Diagrid Framing System<br />
    75. 75. Diagrid Framing System<br />What is it?<br /><ul><li>Short for Diagonal Grid System
    76. 76. Triangulated structure with diagonal support beams
    77. 77. Similar to a typical moment frame
    78. 78. Triangles connected at Nodes and Rings intersect the nodes
    79. 79. Combines the benefits of a hollow tube with a truss
    80. 80. Loads follow diagonals, gravity and lateral loads can be transferred by the system to the ground</li></ul>Swiss Re, London<br />
    81. 81. Diagrid Framing System<br />What is it? (cont.)<br /><ul><li>Can be constructed of either:
    82. 82. Steel (most common)
    83. 83. Timber
    84. 84. Reinforced Concrete
    85. 85. Steel is typical because of high tensile and compressive strengths
    86. 86. Essentially marrying columns, diagonals and bracings into one system
    87. 87. Not a new technology, used in early aviation and small-scale structures</li></li></ul><li>Diagrid Framing System<br />Load Transfer<br />1.) Vertical Loads<br />2.) Lateral Loads<br />
    88. 88. Diagrid Framing System<br />Load Transfer<br /><ul><li>Load transfer happens primarily through diagrid
    89. 89. Internal Cores will transfer minimal amounts of gravity loads
    90. 90. Floor Slabs do not have to transfer lateral loads
    91. 91. Less internal columns required = more space
    92. 92. Floor plates do not have to be of the same shape on each floor
    93. 93. Continuous and Uninterrupted Load Transfer
    94. 94. Rings help to resist Buckling Loads transforming whole system into one big tube</li></li></ul><li>Diagrid Framing System<br />Advantages of this System<br /><ul><li>Structurally very strong
    95. 95. Less material required (~20% reduction in steel as opposed to typical moment frame method)
    96. 96. Aesthetically Pleasing – Blends in together with façade
    97. 97. Floor plan becomes open and free – more internal space
    98. 98. Most forms can be created with a triangulated form – architectural freedom
    99. 99. Self-reliant structure, simple in shape</li></li></ul><li>Diagrid Framing System<br />Advantages of this System (cont.)<br /><ul><li>Simple Construction Technique
    100. 100. Skyscraper Structural Failure minimized by diagrid construction
    101. 101. Better ability to redistribute loads than a moment frame (Failure of one portion does not mean complete structural failure)</li></li></ul><li>Diagrid Framing System<br />Disadvantages of this System<br /><ul><li>Not thoroughly explored for skyscraper construction yet
    102. 102. Inexperienced construction crews
    103. 103. A diagrid structure will definitely show in the aesthetics, very difficult to hide
    104. 104. Difficult to create a consistent window design
    105. 105. Heavy-handed if not executed properly
    106. 106. Material usage can be very excessive if loads are not high</li></li></ul><li>Other Structural Features<br />
    107. 107. Other Structural Features<br />Connections – Butterfly Plates<br /><ul><li>Critical Members in the Structural System
    108. 108. Must ensure a “strong joint-weak member” system
    109. 109. Must resist maximum probable load from braces with minimum yielding and stress concentration
    110. 110. Butterfly plates used to assist smooth load transfer
    111. 111. Finite Element Analysis of Connection</li></li></ul><li>Other Structural Features<br />Connections – Butterfly Plates<br />
    112. 112. Other Structural Features<br />Foundation – Piled Raft <br /><ul><li>Total Settlement estimated as <100mm
    113. 113. Differential Settlement kept to 1:500
    114. 114. Piles are 1.2m diameter and 35m long
    115. 115. Piled Raft is 7m thick and has a footprint greater than the towers
    116. 116. Tension piles used away from towers to resist uplift pressures</li></li></ul><li>Other Structural Features<br />Load Transfer Assistance - Trusses<br /><ul><li>Hidden from view for architectural purposes inside
    117. 117. Link up external columns with internal steel core via pin-joints
    118. 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. 119. Major trusses located at building base (podium) to support the above loads</li></li></ul><li>Other Structural Features<br />Load Transfer Assistance - Trusses<br />
    120. 120. Other Structural Features<br />Building Internal Cores<br /><ul><li>Three main cores accommodating elevators
    121. 121. Cores remain vertical despite Tower Slope (shifted against floor plates)
    122. 122. One core dedicated to “Grandness” (Administrative), the other to “Newness” (News & Technology)</li></li></ul><li>Miscellaneous Topics<br />
    123. 123. Miscellaneous Topics<br />Construction Procedure<br />
    124. 124. Miscellaneous Topics<br />Seismic Stability Design Approach<br /><ul><li>CCTV Performance-based Design for Seismic Stability well outside National Building Codes
    125. 125. Analysis for different seismic events
    126. 126. Level 1: Frequent Earthquake  No structural damage
    127. 127. Level 2: Intermediate Earthquake  Repairable Structural Damage
    128. 128. Level 3: Rare Earthquake  Severe Structural Damage permitted, must not collapse</li></li></ul><li>Miscellaneous Topics<br />Seismic Stability Design Approach<br /><ul><li>Other Research shows test results depicting Overhang vertical displacement with time during an Earthquake
    129. 129. Tests also show that some braces go into plastic buckling during the Earthquake  Dissipate seismic energy (GOOD)</li></ul>Maximum downward displacement = 700mm<br />
    130. 130. Miscellaneous Topics<br />Dealing with Wind<br /><ul><li>Wind Tunnel Experiments had to be carried out to assess the severity of Wind Loads
    131. 131. Building strength against a 100-year Wind was assessed
    132. 132. Method: Dynamic Analysis using High-Frequency Pressure Integration Method
    133. 133. 285 Pressure Taps installed on 1:500 Scale Model
    134. 134. North and West Winds Critical
    135. 135. Southwest Wind worst for Vertical Loads</li></li></ul><li>Miscellaneous Topics<br />Emergency Scenarios<br /><ul><li>In 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?</li></li></ul><li>Miscellaneous Topics<br />Emergency Scenarios (cont.)<br /><ul><li>Numerous Escape Routes
    136. 136. Looped Structure an Advantage
    137. 137. Reduced Escape Time
    138. 138. Better Safety</li></li></ul><li>The Other Buildings<br />
    139. 139. The Other Buildings<br />The TVCC Building<br /><ul><li>Hotels, Theaters, Cultural Center for Performing Arts</li></li></ul><li>The Other Buildings<br />Service Building & Media Park<br /><ul><li>Service Building: Energy Center, Guards Dormitories, Major Broadcasting Vehicle Garages, Fire Control Center
    140. 140. Media Park: Social Gathering place, filming options</li></li></ul><li>Construction Progress<br />Latest Pictures of the Building<br />Dated June 2008<br />
    141. 141. Conclusion<br />
    142. 142. Conclusion<br /><ul><li>Building is to become an icon of Beijing’s Cityscape once completed and will play an important role for the 2008 Olympics
    143. 143. Architecture looks at iconography rather than the race for height – engineering creativity is better than height
    144. 144. Many structural challenges to overcome in realizing the project  Performance-based design needed
    145. 145. Diagrid System, Butterfly Plates, Piled Raft Foundations, Load Transfer Trusses all deemed good solutions
    146. 146. Seismic and Wind Stability ensured through rigorous analysis
    147. 147. Emergency Escape Routes are effective
    148. 148. Other buildings on-site serve unique functions</li></li></ul><li>References<br />[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<br />[2] CB Richard Ellis, (2007), “The CCTV Tower: Central Icon of Post-Urban Beijing?”, CBRE Research – Asia 2007 Issue 1<br />[3] “CCTV Address”, China Academic Journal Electronic Publishing House,, Last Accessed 25th May 2008<br />[4] “CCTV by OMA”, A+U Architecture & Urbanism July 2005 Special Issue, Tokyo, Japan<br />[5] “China Central Television (CCTV) Headquarters”, Design Build Network,, Last Accessed 25th May 2008<br />[6] Koolhaas, R., (2004), “Beijing Manifesto”, Wired Issue 8 2004<br />[7] Lee, S., “Nonlinear Dynamic Earthquake Analysis of Skyscrapers”, CTBUH 8th World Congress, Dubai 3-5 March 2008<br />[8] McCain, I., “DiaGrid: Structural Efficiency & Increasing Popularity”, http://, Last accessed 25th May 2008<br />[9] “OMA – New Head Quarters – Central Chinese Television”,,, Last Accessed 25th May 2008<br />[10], “2008 Olympics: New Towers for a New Superpower”, UK Telegraph,, Last Accessed 25th May 2008<br />[11], “China’s ambitious building passes key test”, UK Telegraph,, Last Accessed 25th May 2008<br />[12] Xie, J. , To, A., “Design-Oriented Wind Engineering Studies New China Central Television Headquarters”, Technotes Issue No. 26, RWDI Consulting Engineers & Scientists<br />
    149. 149. Questions<br />