All language subtitles for Impossible Engineering s01e03 Skyscraper of the Future.eng

Today,
on "Impossible engineering,"

the Shanghai tower,

the most technologically
advanced skyscraper

on the planet...

...built to withstand
earthquakes and typhoons...

...using technology never before
seen in a skyscraper...

...to make the impossible
possible.

Captions by vitac
www.Vitac.Com

captions paid for by
Discovery communications

Shanghai is a megacity.

With 24 million inhabitants
and rising,

it's one of the most densely
populated cities in the world.

With a population of
10,000 people per square mile,

the only place
left to build is up.

By the mid 1990s,

development reached an area
of farmland

on the east river bank
known as Pudong.

And in 2008, work began

on the most impressive building
of them all...

The Shanghai tower.

Over 2,000 feet tall,

it's the second tallest building
in the world

and the tallest ever built
in a seismic zone.

It's the most technologically
advanced skyscraper

on the planet,

with 128 floors
and 9 indoor gardens,

where 16,000 people
will work, sleep and play.

It truly is a city in the sky.

For lead structural engineer
Dennis Poon,

the project was
an exciting challenge.

The engineering challenges
for the Shanghai tower

began at its foundations
because, not only

is Shanghai in an active seismic
and typhoon zone...

...it's also sinking.

The land
under this massive Metropolis

is deflating
like a giant air mattress.

It's shallow-water table

is collapsing under the weight
of the city's modern buildings.

Solid bedrock is 650 feet down.

Above the bedrock is a soft
layer of sand, clay, and soil.

Without a solution,

the 850,000 ton Shanghai tower
would surely sink.

The engineers
only have one shot.

There's no room for error

when you're building a tower
this tall.

A modern world
full of skyscrapers

was once inconceivable.

Early man was limited
by what nature provided.

Ah!

Aw... For the ancient Egyptians,

taller meant wider
and an awful lot of manpower,

unless you believe in some of
the more otherworldly theories.

When it comes to building
towers,

the ground below has frequently
thrown a wrench in the works.

Mamma Mia!

In order to create
a skyscraper 11 times

taller than Pisa's
famous learning tower,

the designers
of the Shanghai tower

will need to draw inspiration

from the work of a 19th-century
engineering pioneer.

Chicago is home to some of the
world's most iconic skyscrapers.

But just over a century ago,

building anything taller
than just a few stories

was thought to be impossible.

You wouldn't know
it to look at it,

but Chicago is actually one
of the least logical places

that you could ever attempt
to build a skyscraper.

We've got soil here
that is incredibly squishy.

Underneath the kind of
shorter, smaller layer of earth,

we've got a very, very deep
layer of soft, squishy clay.

This is a really difficult thing

to build a skyscraper on
of course because,

when you load the building,
the building's going to sink.

As Chicago began to boom

and property downtown
became more valuable,

the demand to grow higher
and maximize space

posed a problem
for city planners.

Taller buildings
meant heavier buildings.

And, as they had discovered,

there was a limit
to weight the soil could handle.

This is the auditorium building
of Roosevelt university,

designed by Adler & Sullivan
in 1889.

It's a national landmark

and so important to Chicago
as well.

The auditorium building
at Roosevelt university

is 236 feet tall.

When it was completed in 1889,

it was the tallest building
in the city.

The radical idea
that made this building possible

came from engineer
Dankmar Adler.

We're headed down to see Adler's
specially designed foundations

to deal with the soil
here in Chicago.

Previously,
the weight of a building

would bear down on its walls.

It would sink into the clay
like a cookie cutter.

Adler's idea was to use wood
and steel crossbeams

encased in concrete to create
a reinforced concrete raft

for the 110,000 ton
building to sit on.

I'm gonna illustrate what's
happening here with this piece

of modeling clay used
to represent the clay

that's under our feet
here in Chicago, this sort

of peanut-butter-jelly-like
substance.

The clay is really quite deep,

and the bedrock
doesn't start in Chicago

until 75 to 100 feet
below the surface.

So I've got my chopstick here
to sort of illustrate.

And I take my structure,

and I go through the hardpan.

And they just didn't
have the technology in the 1880s

and the 1890s to excavate
that far down to bedrock.

So instead, architects
and engineers here in Chicago

are coming up with new ways
to solve this problem.

The method
that we're standing on here

is sort of the equivalent

of this kind of penny
that I'm gonna illustrate.

So this pad
or this raft is put down,

and then the building,
the column on top of that

is put on top of that.

And you can see that I
can push it down a little bit

into the clay, but
not really that far.

This is distributing the load.

Adler's revolutionary
engineering solution

proved that building on
substandard soil was possible.

Today,
Chicago's tallest building,

the Willis tower,
is 1,450 feet tall.

That's more than six times
the height

of Adler's auditorium.

But despite its influence
on the world of skyscrapers,

Adler's design wasn't perfect.

So, on the north edge
of the building,

we've got this large,
heavy exterior walls

that are much heavier
than what...

What's happening on the interior
of the building.

And we can see the challenge
with that,

the fact
that this is much heavier

and this is much lighter
in the building

with this long crack
here in the floor.

We can also illustrate that
pretty well with these marbles.

Dennis Poon
and his engineering team

may owe a debt to Dankmar Adler,

but they can't afford to have
the Shanghai tower subside

like the Chicago auditorium.

They'll have to take
Adler's innovative idea

and supersize it.

At 2,073 feet tall,
the Shanghai tower

is the second tallest building
in the world.

Engineers can't afford
to have it sink unevenly

like Dankmar Adler's
19th century Chicago auditorium.

So Dennis Poon
and his team of engineers

have taken Adler's concrete raft
design and supersized it.

In 2008, the two-year operation

to build the Shanghai tower's
foundation begins.

First, they sink hundreds
of deep supporting piles

into the soil.

Then, they pour the concrete
raft or mat foundation.

It takes 60 hours
of continuous pouring

to create the concrete raft.

2,000 workers
and 450 concrete trucks

are needed
to complete the operation.

The mat soaks up over 2 million
cubic feet of concrete,

breaking a world record.

Without the revolutionary work
of Dankmar Adler,

building a tower this tall
on the soft Shanghai soil

would be impossible.

But the foundation
of the Shanghai tower

is just the beginning.

The tower's structure
must be strong enough to support

128 floors,

each weighing
in at around 6,500 tons.

To design a structure
with the strength

to support over 800,000 tons,

Dennis and his team look
to past engineering solutions

for the answer.

At one time,
the height of a building

was determined by the thickness
of its walls

because the weight of each story

had to be supported
by the floors below.

Tall buildings were the realm
of the rich and powerful.

Medieval religious architects
figured out a way

to design thin walls with large
stained glass windows.

But they needed
external supports

called flying buttresses.

These made the buildings

grow sideways and were exclusive
to the wealthy church.

Bless you, my child.

But there was
a revolution on the horizon.

And this picturesque region
surround the river severn

in england
was at the center of it all.

Shropshire was at the heart
of the industrial revolution.

It was the silicon valley
of the 18th and 19th century.

It's engineers were at
the cutting edge of technology

because they had mastered
the production of iron.

This area gave birth

to some of the greatest
engineering pioneers of our time

and enabled the construction
of iconic structures

like this... iron bridge,

the first cast-iron bridge
of its kind in the world.

But just a few miles
upriver is a less iconic

but much more significant
building.

It wasn't until
about 20 years ago

that the historical
importance of this building

was properly understood,

which is why its fallen
into disrepair.

This crumbling mill is one
of the most important buildings

in architectural history.

This incredible,

but rather sad and dilapidated
building in shrewsbury

is arguably the world's
first skyscraper.

It's the first time that iron
was used

in a multistory
frame construction.

And it really paved the way

for tower blocks and skyscrapers
that we know today.

Built in 1796,
ditherington flax mill

was the brainchild
of engineer Charles Bage.

He took advantage of
the region's groundbreaking use

of iron to build
the first metal-framed building

on the planet.

Previous to the iron frame,

the taller the building,

the thicker the walls
had to be to support them.

But with Bage's design,

the walls could be thinner,

which meant that the rooms
could be much larger.

It also meant that you could
design buildings much taller.

In Bage's design,
the weight of the building

lies on its iron frames
instead of the walls,

making the sky the limit
for the first time.

This main building
had five floors,

including this attic,
which was previously unheard of.

It had a working area
of over 2,800 square meters

or 31,000 square feet.

And these narrow, relatively
lightweight metal beams

would be able to support
much more weight

than the solid brick walls
of previous buildings.

Bage's simple
but brilliant design

made the flax mill
the forerunner

of almost every
large-scale building

in the modern world,

including the Shanghai tower.

What Bage achieved in this
building was truly remarkable.

Today's engineers

are using the same principles
employed by Charles Bage...

But with some revolutionary
engineering of their own.

The 128-story Shanghai tower

will have a steel frame
instead of iron.

Because the steel frame bears
the weight of the structure,

the external walls no longer
need to be load-bearing.

They don't even need
to be flat or straight.

They can be made from a variety
of lightweight materials,

even glass.

Architects can mold the external
walls into any shape they want.

The whole building
is covered in glass.

The glass is suspended
over many floors,

like a giant curtain,
thanks to the strength

of the steel rods
that hold them in place.

Because of the Shanghai tower's
lattice-like steel frame,

its architects
can let the building breathe.

Between the curtain wall
and inner core,

where offices
and hotel rooms are located,

is a massive open atrium.

But creating a skyscraper

in which 16,000 people work,
sleep, and play

comes with a unique challenge...

How to move all those people
around the massive structure.

With 24 million inhabitants,

Shanghai is one of the most
densely populated cities

on earth.

The only way to expand
is by going up.

Over 2,000 feet tall,

the Shanghai tower
is a city in the sky.

It will house offices, shops,
and hotel rooms,

as well as concert halls
and conference rooms.

But building a supertower
in which 16,000 daily users

will work, sleep, and play
poses a unique challenge...

How to transport
all those people

around the massive structure.

It's an engineering feat

that would've been impossible
just a few centuries ago.

By the mid 19th century,

the world's skylines were
still relatively skyscraper-free

for one reason... no one
wanted to take the stairs.

Today, penthouses
rule the top floor.

But back then, the higher
you lived, the poorer you were.

Mustn't grumble.

Steam-powered and hydraulic
lifts were being used in mines

and factories for freight,

but they were too dangerous
for people.

The ropes on the pulley system
would often break.

But city skylines
were about to change because,

in 1852, a man named Elisha Otis

came up with an idea
that would revolutionize the way

the world thought
about living on the upper floor.

He pioneered a simple mechanism

that changed the elevator
forever.

So we're here
in Bristol, Connecticut,

at the Otis elevator
company test facility.

This is where they
test the newest elevators

that they're gonna install
in buildings across the world.

But they also have this replica
of a device that Elisha Otis

first constructed for
the crystal palace exhibition,

the world's fair
that ran from 1853 to 1854.

Otis was a showman as much
as he was an inventor.

The world's fair was the perfect
stage for his invention.

He knew that the eyes
of the world would be upon him

if he could prove that elevators
can be both safe and practical.

So I think it's important
to remember that Otis

didn't invent the elevator.

Certainly, there had been ways
of moving goods and people

up and down from floor to floor

using hoists and pulleys
for... for centuries.

But what Otis did do
was to recognize

that people were afraid
of going into an elevator.

So at the 1853-1854
world's fair,

he builds this... this device
to provide a break, a safety

in case the rope broke.

Like a true showman,

Otis decided that the best way
to prove his idea

was to put it to the test
using himself as a Guinea pig.

In front of a live audience,

he stepped onto the platform,
rose above the crowd,

and gave the signal for the rope
of his elevator to be cut.

So let's see if
Mr. Otis' invention still works.

Ready whenever you are, rich.

Otis' system
features a wagon spring.

It's held up by a rope,

keeping the spring
in a state of constant tension.

When the rope is cut,

the tension
in the spring releases,

causing pins fixed
to the side of the spring

to lock into a ratchet
located in the wood frame.

This brings the elevator
to a complete stop,

preventing it from falling
and injuring any passengers.

And all these years later,

every single elevator today
around the world

has a similar safety device

that is allowing passengers
to feel safe in tall buildings.

And I didn't plunge to my death.

Otis' invention transformed
the world's skylines.

Cities like New York
that couldn't expand sideways

could now reach for the skies.

In 1913, it was the Otis company

that was commissioned
to provide the elevators

for one of New York's
most iconic skyscrapers...

The woolworth building.

By 1916,
more than 100,000 people

had paid their 50 cents
to ride the elevator

to the observation deck
at the top.

And now, 100 years later,
those original Otis elevators

are still being used to carry
office workers up and down.

Because of Otis, instead of
the poor being consigned

to a building's upper levels,

the value of floor space now
increased as you went higher.

Penthouse living was
what everyone dreamed of.

As we drive through New York,
it's easy to forget, I think,

that within just a short span
of time,

just about 160 years,

all of these skyscrapers
have been constructed.

And so the rise of the elevator

and the rise
of the skyscraper are so,

so closely linked.

Otis' first passenger elevator
traveled 8 inches a second.

At that speed,
it would take nearly an hour

to reach the top
of the Shanghai tower.

The Shanghai tower
will have 106 elevators,

including one that travels

a world-record-breaking
1,898 feet.

Along with residents, shoppers,
and office workers,

the elevator will transport
thousands of tourists

to its top-floor observation
deck each day.

The Shanghai tower is the most
technologically advanced

skyscraper in the world,

the tallest building in China

and the tallest ever built
in a seismic zone.

This massive skyscraper
contains 106 elevators,

moving thousands of tourists,
residents, shoppers,

and office workers throughout
the structure each day.

The Shanghai tower
provides stunning views

of the city below,

but it's also a massive obstacle
to the wind.

Shanghai is in a typhoon zone.

Defending the second tallest
building in the world

from the powerful winds

that sweep through the city
is a major challenge

for Dennis Poon
and his engineering team.

Building the Shanghai tower
without first testing its design

in a wind tunnel
would be inconceivable.

But it wasn't always this way.

The first wind tunnel
was constructed in 1871,

but they were
traditionally built

with airplane testing in mind.

That was
until engineer Jack e. Cermak

designed the first wind tunnel
meant for buildings.

In the late 1950s, Cermak
and his contemporaries

pioneered the use
of new wind tunnels.

Professor Rhys Morgan

is visiting
wind engineering firm rwdi.

They take advantage of
Jack Cermak's innovative design,

which is much larger
than a traditional tunnel

and uses irregular shapes

to mimic the unpredictable
nature of the wind.

Blocks like these on the floor

create the kind
of turbulent atmosphere,

turbulent winds that you see
in cities and urban environments

so they're perfect
for testing structures

that we want to build in cities.

One of the first
skyscrapers to be tested

in Cermak's wind tunnel was
New York's World Trade Center.

The discoveries made
while testing the twin towers

influenced the design of
every skyscraper that followed,

including the Shanghai tower.

A scale model
of the World Trade Center

is being placed into a model
of the London skyline

to demonstrate the effect wind
can have on tall buildings.

Wow, it's really windy.

As wind
rushes past the structure,

it forms into Eddies
of low pressure on either side.

So the wind is coming in here.

It's hitting the side.

And then,
as it comes around the corner,

it produces a low-pressure
region here.

And that causes the movement...

The building to move this way.

But then that means that
the wind coming around this end

starts to cause a little bit
of movement

this side and low pressure.

So we start to get
this low pressure,

low pressure, low pressure,
low pressure.

And that causes this oscillation
back and forth.

This is just amazing.

This is the kind of... this is
real engineering happening here.

That's moving a good
5 centimeters either side.

I wouldn't want to be on the top
of this building if it was a...

A real building in the city.

For architects, the challenge
is to come up with a shape

that reduces those vortices.

Okay, let's try this one.

This time,
the building is tapered

like an elongated pyramid.

You can see there's very,
very little movement.

Let's turn it up a bit more.

We're running at three times

the wind speed of that very
first model that we saw.

And the building's just not

moving anything
like as violently.

Because of the tapered shape
of the building, the wind

creates vortices of different
sizes at different heights.

It's causing some oscillations
down here,

but then much slower
than the oscillations

occurring at the top end.

Different parts of the building

are trying
to shake at different rates,

canceling each other out.

And so it prevents the building

from oscillating
quite so violently.

Jack Cermak's wind tunnel

allowed city skylines
around the world

to grow taller safely.

Today, no one would think
of building a skyscraper

without testing it first
in a wind tunnel.

The Shanghai tower is tapered,

but it also has
a distinctive twist,

a direct influence
from wind tunnel testing.

It's a unique design

that reduces wind loads
on the building by 24%.

Architects also designed
a notched "v"

running the entire length
of the building.

The notched- "v" shape
on the Shanghai tower

started out
as an aesthetic touch.

But when engineers
tested it in a wind tunnel,

they made a surprising
discovery.

The Shanghai tower

is the most technologically
advanced skyscraper in the world

and the tallest building
in China.

The tower's tapered,

notched- "v" design maximizes
its aerodynamic performance,

making it one of the most
wind-resistant skyscrapers

on the planet.

But the Shanghai tower
faces a natural force

even more destructive
than high winds...

Earthquakes.

Shanghai is in a level three
seismic zone.

Building the Shanghai tower
strong enough to survive

an earthquake
will be a daunting task.

Earthquakes can be

some of the most devastating
natural disasters on the planet,

leveling buildings
and triggering tsunamis.

China's neighbor, Japan,

is the most seismically active
country on the planet.

But for years,
no one could understand

why modern buildings
would collapse in an earthquake

while traditional pagodas
stayed standing.

The secret to the pagoda's
survival is hidden inside.

The typical pagoda
consists of five floors.

Its floors have the ability

to move independently
of each other.

When an earthquake strikes,

its snake-like pattern
keeps the center

of gravity more upright
than a rigid building would.

And the wooden joints
that support each floor

are made up of several
separate components

so each part can slide and move.

The friction the parts
create acts like a damper

to soften any movement.

Today's engineers will need to
take the five-floor pagoda's

innovative
earthquake proof design

and apply it to
the 128-floor Shanghai tower...

...with a 21st century twist.

The Shanghai tower's design
is similar to an ancient pagoda.

Its structure is divided
into nine vertical zones

around a central composite steel
and concrete core.

To further strengthen the tower,

huge perimeter columns
and outriggers

have been attached
to the central core.

The earthquake-proofing measures

extend from the base
of the tower to its tip.

So, why is this room
so important?

The answer is suspended
above Dennis' head.

So, why would engineers
take up valuable floors

and sacrifice the revenue they
can generate with a steel block

the weight
of 600 four-door sedans?

Boston's John Hancock tower
was completed in 1976.

Its futuristic, glass-clad
design was ahead of its time.

But not long after it opened,

upper-floor occupants
complained of motion sickness

as the building
swayed with the wind.

Engineer William lemessurier

came up
with an ingenious solution.

What I've got here is a very
simple model of a skyscraper.

It's a, um, beam structure
going up several stories.

Turning a handle
at the base of the structure

mimics an earthquake.

With steel structure buildings
and glass buildings,

of course we're reducing
the weight of those buildings.

So you can actually
go much taller.

You can build them much taller.

But then you do have
this problem with sway.

Lemessurier's idea
was to counteract the sway

at the John Hancock tower.

He installed two steel boxes
on the 58th floor.

Each box was filled with
several hundred tons of lead

and placed on a steel plate.

You have to imagine
this is an 800-ton weight

that I'm lifting
up onto my skyscraper now.

And I'm just gonna tie it
to the top of my structure.

The tuned mass damper,

or tmd is became known,
had a dramatic effect.

It's amazing.

The structure is hardly moving.

I mean it's quite phenomenal.

So what we're seeing here
is the mass damper oscillating

out of phase with the vibration
of the structure.

In a building like this,

you wouldn't have an 800-ton
ball flying around violently

and smashing into the walls.

The principle is simple.

As the building sways one way,

it pulls the damper with it.

As the building
starts to sway back,

the damper is still traveling
in the opposite direction.

So it stops the building
from going too far.

It's amazing how, uh,
how much of an impact it has.

It really does just stop the
structure from swaying around.

Without tuned mass dampers
today, uh, we just

wouldn't have any of the kind
of megastructures that we have.

The Shanghai tower's engineers

have taken lemessurier's damping
system to a whole new level.

Despite taking up five floors
and weighing over 1,000 tons,

the Shanghai tower's
tuned mass damper actually

makes the building cheaper
and lighter to construct.

It took 15 years
of planning, design, and testing

and 7 years of construction
to raise this supertower

from its foundations
deep in the Shanghai soil

to the tip of its 128th floor
over 2,000 feet up.

By drawing on innovations
of the past and making

groundbreaking discoveries
of their own,

the engineers, designers, and
workers of the Shanghai tower

have overcome unstable soil,

high winds, and earthquake risks
to make the impossible...

Possible.

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