Burj Khalifa – How To Build Higher


Earlier this month I made a trip from Ireland
to Dubai and as the plane climbed to cruising altitude we were treated to the most amazing
sunset, from 12 kilometres in the sky. I had this moment of awe and gratitude that
we live in a time where experiences like this are possible and the feeling just got stronger
when I arrived in Dubai and saw the Burj Khalifa. The building defies belief, I lived in Malaysia
for 3 years and used to love watching the Petronas twin-towers glimmering in the distance
as I drove through the hills of Bangsar. Those towers held the title of the tallest
building until 2004, but the Burj Khalifa is almost twice the height. I found myself looking up the tower and where
I expected it to stop it just kept going, soaring further than I thought possible. It really got me thinking about how it’s
engineers managed to overcome the challenges that faced them. The battle to build higher captured the world’s
attention in the 1929 as the Chylser building raised it’s secret spire like a proverbial
middle finger to the Bank of Manhattan Trust building, after months of intense competition
to become the world’s tallest building. It cemented Chrysler as a powerhouse in the
American automotive industry, becoming a symbol of the company’s power and technological prowess. The soaring skyscrapers of Manhattan were
not only a symbol of the power of the companies that built them, but were seen as an expression
of America’s optimism and wealth. The explosion in growth in America was largely
fueled by the invention of the elevator and the availability of cheap structural steel. Frank Lylod Wright even proposed a The Illinois
a 1.7 kilometre tall building in 1956 and while the building was theoretically possible,
it was completely unpractical. Elevator technology had not advanced far enough
and building sway would have been a huge issue for comfort. Tall slender structures like this are susceptible
to wind induced vibrations. Anyone that has seen lamp posts shaking in
the wind will have seen this in action. So what’s happening here? Let’s place a cylinder in a wind tunnel
and examine what happens as we increase the air velocity. In a steady flow of air, you would assume
that the net force on the cylinder would be in the same direction, like this. And you would be right, at lower speeds this
is the case. Here the light pole would just bend in that
direction and while the wind speed and direction may fluctuate, you wouldn’t see the consistent
back and forth vibrations. As we increase the speed, the air begins to
separate from the surface of the cylinder creating two symmetrical eddies behind the
cylinder. Eddies are regions of slow moving swirling
fluid. You will see these a lot in rivers where branches
or bridge pillars block the flow. Here is one in my hometown of Galway, Kayakers
use these eddies when they need to rest from the fast moving mainstream. If we keep increasing the fluid velocity these
eddies will grow and the force on the cylinder will also grow, but as long as these eddies
are symmetrical the force will remain in the direction of fluid flow, but there is a critical
moment where the system loses it’s stability. The energy gradient from the main stream and
the slow moving eddies becomes too high and the eddies begin to oscillate, at this point
a phenomenon called vortex shedding occurs and the resultant force is no longer directly
downstream. It teeters between the alternating low pressure
zones as the vortices are shed on either side of the cylinder. This can become a massive issue if the frequency
of the shedding matches the resonant frequency of the structure. That means that the direction of sway and
the direction of the force become synchronised and the amplitude of the swaying is allowed
to grow as energy is being stored between each cycle. Every building dissipates some of that oscillation
energy through natural damping through it’s materials and through friction at the joints,
but this is not always enough. In these cases it is essential that the engineers
add mechanical dampers. These are usually hidden away in the guts
of the building, but the world’s former tallest building, The Taipei 101, decided
to open their 730 metric ton tuned mass dampener to the public. On August 8th 2015 a category 5 typhoon slammed
into Taiwan and set the Taipei 101s mass dampener into motion and it was all recorded on a web
camera. So what’s happening here, how does this
help stabilise the building. When the tower is displaced the mass dampener
does not move with it immediately, it is left behind and then begins to sway independently
of the building. Now this is where the tuned part comes in. The engineers will have tuned the damper to
the same frequency as the building, so when the building sways to the right the damper
sways to the left and vica versa. This creates an opposing force to the sway
which is transferred to the building through these piston dampers and thus the kinetic
energy is dissipated and the magnitude of the resonant motion is reduced. Now what amazes me is that the Burj Khalifa
has no mass damper. It simply relies on clever aerodynamics from
stopping those vortices from ever getting organised enough to cause harmonic motion. The reason light poles sway so easily is that
they have a consistent cross-section, allowing those vortices to slough off uniformly along
the poles height. So the same force is being applied at the
same time along the entire length. One way engineers combat that is by placing
these helical spirals along the length of cylindrical structures. You occasionally see this with chimney stacks,
but also in offshore platforms as vortex shedding can also happen in liquids. The helical fins disrupts the fluid flow along
the length of the hull, preventing the vortices from forming coherently. The Burj Khalifa works in a similar manner
albeit in a much more elegant fashion. The building’s footprint was inspired by
the desert hymenocallis flower and while this is a beautiful design. It provides an optimal amount of window space
while also allowing the steel reinforced concrete frame to take this shape. This central core provides excellent torsional
resistance while these y-shaped buttresses provides fantastic lateral bending resistance,
similar to how an I-beam works. (on screen)I’ll explain that in more detail
in a future video. As the tower grows the building steps back
consecutively like this, This spiralling pattern works exactly like the helical fin on the
platform earlier. It prevents the vortices from sloughing off
the building coherently along it’s length and so stop them from exciting the buildings
resonant frequency. This is the genius of the building and why
is doesn’t need a mass damper. The architects put meticulous care into the
buildings aerodynamic design using modern computational analysis and wind tunnel tests
to ensure the structural integrity of the building. It is clear that with the continuous improvement
of technology, building these supertall buildings is becoming less difficult and we are going
to continue seeing the title of tallest building in the world swap hands in the coming years,
especially as the pressure to build higher grows. In 2007, the total urban population of the
world surpassed the 50% mark, 20 years ago that figure was just 33% and that statistic
is expected to approach 80% by 2050. Creating a functional city with adequate water
and energy supply and everything else that comes with a densely packed population will
become an enormous challenge in the coming years. It is likely that these supertall buildings
will become less of a decadent symbol of power and wealth and become a necessary and fundamental
part of the modern city. Thanks for watching. I really enjoyed making this video and I hope
you enjoyed watching it. I have heard back from loads of you on how
much you are learning from TheGreatCoursesPlus and thanks to your continued support they
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100 Comments

  1. Ehow567 said:

    Tip for the future the s in Illinois is silent

    September 20, 2018
    Reply
  2. Simplicio said:

    1:31 okay im going to need you to say that again

    September 22, 2018
    Reply
  3. Chillity said:

    Lol they got that name from Mia Khalifa

    September 23, 2018
    Reply
  4. BlackWolf6420 said:

    I love your chanel ❤️👍 It keeps answering all the questions from the past.

    September 26, 2018
    Reply
  5. Federal Bureau of Investigations said:

    *says that us Americans can’t pronounce “aluminum”, and yet can’t pronounce “Illinois”… 😂😂 great vid though

    September 27, 2018
    Reply
  6. Zibartski said:

    What car is that?

    September 30, 2018
    Reply
  7. Mr. Engineer said:

    I love your Chanel

    October 2, 2018
    Reply
  8. david konkol said:

    Cough COugh 9/11 Cough Cough

    October 5, 2018
    Reply
  9. Michael Gainey said:

    What happens if it catches on fire? How would they put it out?

    October 7, 2018
    Reply
  10. Stefan Veenstra said:

    How much energy is needed to transport something as essential as water that high up?
    What produces the energy to make it happen and how tall can we efficiently build before such energy source becomes more expensive than their purpose?

    October 7, 2018
    Reply
  11. Antoni said:

    8:00

    October 9, 2018
    Reply
  12. The MozartThug said:

    Bill evans in the background!!!

    October 10, 2018
    Reply
  13. 5.000 subscriptions with no videos said:

    I came here to read clever comments about Mia Khalifa

    October 11, 2018
    Reply
  14. julian braunbeck said:

    couldn't we just build a giant pyramid?

    October 14, 2018
    Reply
  15. puca said:

    UP GALWAY!

    October 14, 2018
    Reply
  16. Steven Ruppe said:

    Superb.

    October 19, 2018
    Reply
  17. Robert H said:

    I imagine that the taller buildings become the more and more challenges will arise. For example, pumping water to the highest floors will become way more challenging

    October 19, 2018
    Reply
  18. Aus penang said:

    Petronas twin tower a tallest twin tower in the world…

    October 23, 2018
    Reply
  19. Exolette said:

    More advanced technology is needed based on where its being built or the environment…
    That's what you're trying to say. 😑

    October 25, 2018
    Reply
  20. Wdcvczx Wcghgfx said:

    Guys! Listen to me! Do not make fun of my favorite building… Burj khalifa!

    October 30, 2018
    Reply
  21. Arish 2101 said:

    6:06 did that ferry just drift?

    November 11, 2018
    Reply
  22. TheGarr123 said:

    @5:50 butt hurt structural/wind engineer here. No… the architects don't do shit, they just dream stuff that we as structural engineers must design. It is the ingenuity of the structural engineers and wind engineers that make most modern tall buildings possible.

    November 27, 2018
    Reply
  23. Graviton1066 said:

    The Burj is a pointless building … even today its not fully occupied … the whole nation of the UAE is a bubble waiting to pop …

    December 1, 2018
    Reply
  24. Just a Devil said:

    what abour Mia Khalifa? ohh..wrong tube

    December 3, 2018
    Reply
  25. ArduinoBen said:

    Isn't the Illinois s silent?

    December 8, 2018
    Reply
  26. Andrew Stirling said:

    The UAE’s engineering is matched only by its tyranny.

    December 9, 2018
    Reply
  27. Structural osama said:

    its a pretty good video

    December 10, 2018
    Reply
  28. TC ON BRENTFORD said:

    I worked for the company which wind tunnel tested the Burj Khalifa, unfortunately that company has now closed the wind tunnels

    December 15, 2018
    Reply
  29. Vinicius Aguiar de Souza said:

    Your videos are awesome!

    December 20, 2018
    Reply
  30. Bear Newman said:

    The name "Khalifa" will forever remind me of someone, not this building.

    December 20, 2018
    Reply
  31. Rahul said:

    Great man! Keep up the hard work (:

    December 26, 2018
    Reply
  32. Dinesh chandra said:

    Nice video

    December 30, 2018
    Reply
  33. Lee Bee said:

    The Burj Khalifa is the best, most beautiful building ever made. I just love it 🙂

    December 31, 2018
    Reply
  34. Cyber XY said:

    fantastic work

    December 31, 2018
    Reply
  35. thearchitect27 said:

    My friend, you should do a part 2 of this video focusing on the sub-structure of the Burj Khalifa! The final product that we see above ground is no doubt amazing, but what is truly fascinating to a structural engineer is the portion of the building BELOW the ground, and in the case of the Burj Khalifa, it's quite an engineering feat unto itself! Think about how deep the foundations needed to have been dug into the sand, then the piles which are another, separate layer of depth. If the above ground structure is about 50% of a mile in the air, then my conservative estimate is that the below ground structure is probably around 25% of a mile in depth. So if measuring for total structure of the Burj Khalifa, it's estimated to be about 75% of one mile, which is truly impressive!

    January 3, 2019
    Reply
  36. Anas Omar said:

    how beautiful when people understands how life works and adapt with it

    January 3, 2019
    Reply
  37. L.H C. said:

    Taiwan-Taipei 101

    January 3, 2019
    Reply
  38. Gerald Pined said:

    Nice video thanks for the info!

    January 4, 2019
    Reply
  39. Cian Doyle said:

    There's a fidget spinner in the thumbnail

    January 8, 2019
    Reply
  40. Donald J. Trump said:

    They should put that balance things on boats when there in the ocean

    January 10, 2019
    Reply
  41. Niall Noonan said:

    I walked across that bridge every day for two years when I lived in galway

    January 15, 2019
    Reply
  42. shivam sharma said:

    great video

    January 16, 2019
    Reply
  43. zoom is epic said:

    r u sure about that

    January 24, 2019
    Reply
  44. buspojk von H said:

    Music in the backgrund is sky by Yiruma

    January 26, 2019
    Reply
  45. Ben Stan said:

    Up the rawww

    February 6, 2019
    Reply
  46. FitzP Official said:

    Thanks for mentioning Malaysia Twin Tower
    Hell of a view.

    February 10, 2019
    Reply
  47. Winter's Destruction said:

    Simplicity is better than complexity.

    February 11, 2019
    Reply
  48. Vikibe K Sumi said:

    I think im in love with buildings

    February 12, 2019
    Reply
  49. Ed Chin yosh said:

    What you been living in Malaysia for 3 year?!?

    February 16, 2019
    Reply
  50. Usama Zafar said:

    Brilliant video covering many aspects of wind engineering. Nice work. Keep it up!

    February 19, 2019
    Reply
  51. Austin S. said:

    The Jeddah Tower is being built in UAE it is taller and better than the Burj Khalifa

    February 21, 2019
    Reply
  52. William Hedger said:

    MALAYSIA IS LIT
    cause I live there…

    February 26, 2019
    Reply
  53. Xern said:

    Nani you lived in Malaysia for 3 years?!?!!

    April 7, 2019
    Reply
  54. zeus lim said:

    Wait, they designed that building after spider lilies?

    April 12, 2019
    Reply
  55. ProPotato jr said:

    next thing you know we have to acclimatize to get to the 3 floor

    April 13, 2019
    Reply
  56. Robert Oates said:

    this is my new v sauce!

    April 16, 2019
    Reply
  57. Tesla Paradise21 said:

    Yeah, but 🗿

    April 16, 2019
    Reply
  58. Golon Wes said:

    The Malaysian towers were NOT ever the tallest building, the Seats tower in Chicago was ALWAYS taller – just look at them side by side!

    April 19, 2019
    Reply
  59. Farhan K said:

    ❤️ from malaysia

    April 19, 2019
    Reply
  60. Tristan Ruel said:

    Did anyone else realize that the length of this video is 7:37?

    April 19, 2019
    Reply
  61. Glay xx said:

    Can you discuss more about core walls/core foundation pls.

    April 25, 2019
    Reply
  62. eerereps said:

    fucken incredible, man!

    May 1, 2019
    Reply
  63. Luke Jagger said:

    Im a simple Malaysian.. I see twin towers I give like

    May 14, 2019
    Reply
  64. Asfulan 345 said:

    Didn't know you lived in Malaysia…..

    May 23, 2019
    Reply
  65. dinesh bhansali said:

    What is resonant frequency of structure?

    May 23, 2019
    Reply
  66. - SÄGI- said:

    Was there a mass damper in the WTC?

    May 23, 2019
    Reply
  67. Suzuki Raider said:

    SAMSUNG made building 👍

    May 27, 2019
    Reply
  68. Chris Schembari said:

    At 4:40 there's a difference between slough ("slou" or "sloo") and slough ("sluff").
    https://www.lexico.com/en/definition/slough

    June 14, 2019
    Reply
  69. Chris Schembari said:

    If we build this tall, I'm confident that we can house trillions of people here on Earth. I didn't see SFIA in your community page, so I hope you enjoy it.

    https://youtu.be/TqKQ94DtS54

    June 14, 2019
    Reply
  70. Roelf Minnaar said:

    I remember the first time I saw th Burj Kalifra. But unfotunatly it was cloudy, so from the plane, all I could see was the top 100 or so meters.

    June 20, 2019
    Reply
  71. منتصر السوداني said:

    Please add Arabic or Chinese with translations💕
    فضلا قم بإضافة اللغة العربية أو الصينية مع الترجمات.

    June 22, 2019
    Reply
  72. Driftliketokyo34 Ftw said:

    Petronas? As in mercedes petronas?

    July 5, 2019
    Reply
  73. M'aiq the Liar said:

    Can't build higher than 256 blocks

    July 12, 2019
    Reply
  74. Stuttershook said:

    As a malaysian i am obviously in awe as he said my countries name outloud
    Those rarely happen

    July 15, 2019
    Reply
  75. XRONO Gaming w/a said:

    cough*limericksbetterthangalway*cough

    July 25, 2019
    Reply
  76. MhaZG said:

    Its 257 blocks i guess

    July 27, 2019
    Reply
  77. Lord Swoldemort said:

    I’m a simple man, i see the name Khalifa, i click.

    July 27, 2019
    Reply
  78. Galacticcore 07 said:

    Hold up your Irish I am I‘am from Co.Dublin

    July 27, 2019
    Reply
  79. Akshay Narkar said:

    Now, where is that fidget spinner the thumbnail promised??

    July 29, 2019
    Reply
  80. The Qoheleth Foundation said:

    I was invited to the grand opening of the Burj Khalifa. I was corresponding with a job recruiting company, Bayt International, and they sent me an email invitation to attend. But I was doing other things, and the finances to fly round-trip to Dubai were also a factor.

    July 29, 2019
    Reply
  81. Victor Beil said:

    Real Engineering:"Burj Khalifa"

    me:"huh, what mia khalifa ?"

    July 29, 2019
    Reply
  82. CrankLetsPlay said:

    With a big Minecraft piston of courses

    July 30, 2019
    Reply
  83. Ben Lamptey said:

    @Real Engineering How about Shenzen's pyramid arcology plan? Is it possible that this race for the tallest building will lead to something like that in the next few decades?

    July 30, 2019
    Reply
  84. Cesar Augusto said:

    Great content

    July 30, 2019
    Reply
  85. Brian Bethea said:

    Slough in this usage is pronounced like tough, with the f sound at the end, rather than like the ow in power. In place names and geographical use (swamps or very muddy areas), it's pronounced as the latter, but if it means to shed or cast away something, as in "The skyscraper is able to slough off the vortices of traditional skyscrapers," it'd be the first. English is a weird language.

    July 30, 2019
    Reply
  86. Daniel Brown said:

    I badly want the helium tower to move forward..

    July 31, 2019
    Reply
  87. Cowlaur99 - dank memes said:

    You sound like RTGame.

    August 4, 2019
    Reply
  88. baller leddy said:

    man i’m from dublin and i like ur vids

    August 5, 2019
    Reply
  89. 김정수 said:

    Interesting thing is all the tallest skyscrapers in the clip Burj Khalifa, Taipei101 and Petronas twin tower..all were all built by Samsung..I guess they’re good at skyscrapers too

    August 10, 2019
    Reply
  90. skrt skrt said:

    6:06 Deja Vu

    August 12, 2019
    Reply
  91. Michael Moravej said:

    Did anyone else from Illinois cringe a little when he pronounced the S

    August 12, 2019
    Reply
  92. Randy farm and lifecraft said:

    Why not build a space elevator from the idea, or something.

    August 13, 2019
    Reply
  93. TitanOfChaos said:

    Is it just me, or foes anyone else think his opening intro is very creepy

    August 13, 2019
    Reply
  94. Nathan Zhang said:

    I thought I saw a fidget spinner on the thumbnail so I came

    August 17, 2019
    Reply
  95. Oh Deer Aulia said:

    NO TOWERS ARE SAFE

    August 19, 2019
    Reply
  96. David said:

    Thank you for sharing I enjoy your channel.

    August 31, 2019
    Reply
  97. Dan Jakubik said:

    Well done!

    September 7, 2019
    Reply
  98. Dan Jakubik said:

    Science and technology minded person here.

    September 7, 2019
    Reply
  99. Ericson Joe said:

    Khalifa?

    Mia Khalifa

    September 10, 2019
    Reply
  100. Andrew Cliffe said:

    Great video

    September 11, 2019
    Reply

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