Skyscrapers

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Skyscrapers

• Construction Technology

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What is the tallest skyscraper?
Burj Khalifa (Burj Dubai) Location Dubai,
United Arab Emirates Stories160 Inhabitable 46
Maintenance Overall Height 2,717 ft Highest
Point of Occupancy 2,038 ft Began
2004 Completed January 2010 Elevators 57
(40 MPH) Architect Adrian Smith Cost 1.5
Billion
Over 2000ft. high!!
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Foundations
Skyscrapers are very heavy, therefore we need to
have a solid foundation. Why?
How do we stop this from happening?
Start on BEDROCK!
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Framing
Skyscrapers are framed using steel columns and
girders.
The outer covering is called a curtain wall.
Check it out!
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Spreading the weight
Spread Footing
Even though the foundation has started on
bedrock, we still need to spread the weight just
to be safe.
How can we do this?
Typically, they use SPREAD FOOTING.
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Wind
Most skyscrapers sway in the wind.
How can we minimize the distance of the sway?
Engineers use TUNED-MASS DAMPERS.

1. A computer detects how far the wind is making the
   building move in one direction.
2. The computer will move a very heavy weight in the
   opposing direction.
3. Within under a minute, the sway is minimized to a
   safe level.

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Tuned-Mass Damper
Notice the size compared to the guy!!
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Earthquakes
Many skyscrapers are built in cities that have
fault lines underneath.
There have been many disasters due to earthquakes.
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How do we minimize damage?
Skyscrapers are built a little more
flexible. Flexibility allows the structure to
twist and turn a little without breaking and/or
crumbling. If the skyscrapers were rigid, pieces
would snap off easily in an earthquake.
What effects do you think this has on the overall
design?
We use damping systems!
ALSO
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Also
Glass is attached using rubber channels.
This allows the glass to move a little bit. It
has a lower change of breaking in an earthquake.
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For Extra Support

• Cross-bracing is sometimes used.

What kind of cross-bracing should be used for
this skyscraper?
Most of the weight is transferred to the center
supports.
Most of the weight is transferred to the outer
supports.
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First and Oldest

• First skyscraper
• Home Insurance Building
• Location Chicago
• Height 138 feet
• Stories 12
• 1885-1931

• Oldest Still Standing
• Milwaukee City Hall
• Location Milwaukee
• Height 353
• Stories 15
• 1895 - ?