Name: How the world’s tallest skyscraper was built - Alex Gendler
Uploaded: 2021-04-25T14:03:16.000Z
Duration: 6 min 8 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

the race to build the world's tallest skyscraper grinded to a halt.

Each new contender was only slightly taller than the one before,

and architects were running out of ways to top their previous efforts.

But in 2004 construction began on a new building in Dubai,

promising a revolutionary design  that would dwarf the competition.

In 2009, the 828-meter Burj Khalifa  was complete,

surpassing the previous  record-holder by over 60%.

So what innovations allowed  for such a huge leap in height?

For most of architectural history, heavy building materials

made it difficult for tall buildings  to support their own weight.

To compensate, taller structures had  wider, thicker masonry at the base,

making them substantially more expensive.

The arrival of industrial steel  in the early 20th century

helped buildings shed weight,  and stretch to new heights.

But steel frames required intensive labor to produce,

these three dimensional grids took up huge amounts of space inside buildings.

Tall steel skyscrapers also had  larger, less dense surfaces,

Architects designed various  countermeasures

to prevent swaying and structural damage,

engineers would have to completely rethink how tall buildings were designed.

Enter the father of modern skyscrapers: Fazlur Rahman Khan.

This Bangladeshi-American engineer believed tall structures

should bear their weight where they were  widest and most stable— on the outside.

He proposed swapping an internal grid  of steel beams

that would make buildings more resilient to wind

Khan developed this idea into what he called tubular designs.

These buildings had exterior steel frames that were braced with concrete

Tubular frames proved superior at absorbing and transferring

the force of wind to a building's foundation.

And since the exterior walls could bear the bulk of the load,

internal supporting columns could be removed to maximize space.

Following the 1960s, tubular design became the industry standard.

This new philosophy allowed  for the construction

including many of the record holders  for world's tallest building.

But planning the Burj Khalifa would take one more innovation.

In 2004, the late Fazlur Khan's  longtime employers,

Skidmore, Owings & Merrill, completed  the Tower Palace III in South Korea.

This building took Khan's exoskeleton design one step further,

with a central column supported by three protruding wings.

Each wing's weight carries the other two,

while the heavy concrete core acts  as a support beam,

that also houses the building's elevators  and mechanical infrastructure.

allowed the entire structure to work  as a single load-bearing unit,

SOM was confident the buttressed core could support a much taller building,

and they were determined to see how high they could go with their next project.

As only the second building to use this design,

the Burj Khalifa spans  an unprecedented 163 floors.

To battle the monumental  vertical and lateral forces,

the design strategically places  the strongest, load-bearing areas

Additionally, the Y-shaped layout  was specifically calibrated

Every several floors,  one of the wings recedes slightly,

forming a series of setbacks in a clockwise pattern.

This spiral shape disperses air currents,

transforming 240 kilometer per hour winds into harmless gusts.

Considering its height and unique design,

the Burj Khalifa was completed  in a staggeringly short five year period.

However, this pace came at a great human cost.

The workforce consisted mostly  of South Asian migrants,

who regularly endured shifts  over 12 hours long

Those who tried to quit or return home  had their paychecks and passports withheld

These abusive conditions led to multiple protests,

in addition to at least one suicide,  and one fatal accident reported on site.

In the years following  the tower's completion,

the United Arab Emirates fell under harsh scrutiny

for failing to enforce worker protection laws.

Hopefully, future projects will prioritize the individuals

behind these engineering marvels  over the buildings themselves.

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How the world’s tallest skyscraper was built - Alex Gendler

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