All language subtitles for Impossible Engineering s03e06 The Invincible Tower.eng

Today on
"Impossible Engineering,"

the Tokyo Skytree,
the world's tallest tower.

It's a striking landmark.

The world's number-one tower.

To take structural
design to new heights...

If you don't get
the foundations right,

then that's a recipe
for disaster.

...Engineers must look

to the innovative pioneers
of the past...

This is unbelievable.

This rocket is just so big.

...To make
the impossible possible.

... Captions by vitac...
www.Vitac.Com

captions paid for by
discovery communications

Tokyo... home to
over 35 million people.

With suburbs stretching
14,000 square miles,

its vast sprawl
of low-rise buildings

is a direct result of

one singular environmental
challenge...

earthquakes.

But for the first time,

as space in this mega-city
runs out,

engineers must now look up.

As taller buildings rise,

an expected challenge emerges,

especially for the city's

nearly 1,100-foot-tall
communications hub,

the Tokyo tower.

Everyone here,

including high-rise architect
David Malott,

can clearly see the problem.

You can almost see
it's going to be

knocked out by a building.

The signal is being blocked.

In a nation that experiences
1,500 earthquakes a year,

uninterrupted TV and radio
communication is vital.

This problem requires
a radical solution.

Here it is... Tokyo Skytree.

Unprecedented in Japan,

the Tokyo Skytree is the world's
tallest free-standing tower.

It's double the height
of Tokyo tower.

It's got the most advanced
engineering and technology

we have available today.

This is the solution
for Tokyo's connectivity.

For designer Tetsuo Tsuchiya,

scaling these heights
offers a unique challenge.

The record-breaking
2,080-foot-high structure

is more than four times

the height of
the great pyramid of Giza.

Its spine is a 1,200-foot
hollow concrete core

cloaked in a 37,000-piece
steel frame

which morphs from a triangle
to a circle.

It has two observation decks.

The tallest,
at almost 1,500 feet,

is one of the highest
in the world,

and it's topped by
the state-of-the-art

antenna tower capable
of transmitting 62 miles away.

Construction begins in 2008,

but before Skytree can even
rise above the ground,

its designers face
a seemingly impossible problem.

Where we are now used
to be part of Tokyo bay.

The land I'm walking
on was underwater.

So what that means is the soil
around here is extremely soft.

And, for engineers,
this presents a big challenge,

especially when you do something
of that height

in a place that has earthquakes
and typhoons.

It's going to want
to push the building.

So that building needs to be
firmly anchored into the ground.

If you don't get
the foundations right,

then that's a recipe
for disaster.

With this colossus exerting
over 75,000 tons of force,

how can you ensure
it will remain

standing on unstable soil
during an earthquake?

To accomplish the impossible,

engineers must look to the past.

Hmm?

It might be far from perfect,

but soft ground has rarely
scared away history's engineers.

Oh, forget it.

Olé!

In fact, some of
the world's most famous cities

had been built on swamps
and marshes.

Bravo.

I'm getting wet.

In New Orleans,
the ground is so soggy,

the city famously had

to build their cemeteries
above ground.

Ah, that's better.

And Berlin is criss-crossed

by a constantly changing
40-mile network

of pink pipes used
to pump the ground

free of water.

Whew.

Ah, wunderbar.

Architectural
historian Jen Masengarb

is exploring San Francisco

to find out how
the 1848 gold rush

ultimately sparked
an engineering revolution.

To serve this booming bay area,

architects constructed
the monumental

new ferry building.

It weighs about
150 million pounds,

which translates
to about 75,000 tons.

Not only does it stand
in a seismic zone,

the building's 245-foot tower

and extreme weight both rest
on 180 feet of bay mud,

creating near impossible
building conditions.

So those tasked with designing
a new ferry building

really had to think
about innovative solutions

in order for the building
to be successful.

To support this grand
architectural design

on unstable grounds,
engineer Howard Holmes

had to look beyond
traditional methods

and dig deep.

I've got some wet sand,
which is the same kind of sand

that's here
underneath the ocean,

and this wooden plank
is to help us

see that concrete mat

the entire building
is sitting on.

And these nails
are those wooden piles

that are driven
down to the sand.

In a typical building,
you might use only as many piles

as you would need
to support the building.

So let's see fit that works.

I can put quite a bit
of load on this,

but we're in a seismic zone.

You can see that I can turn
this sideways pretty easily.

So wiggle, wiggle, wiggle.

But to survive earthquakes,

the new ferry building
needed something more.

So, here's my new demonstration
with lots of piles.

Wow. Not only can
I not push it in very much,

but when I try to wiggle it side
to side, I really can't.

And the secret of this stability

is due to the friction.

Friction is created around

the surface area
of each of these piles,

and more piles equals
more surface area.

And because it's much
more stable like this,

any earthquake load,

all of those forces
are just going to be absorbed

by all the piles,

making the rest of the building
much more secure.

Brilliant.

Over 5,000 wooden piles

extend deep into San Francisco's
semi-fluid Sandy mud.

These support the structure's
111 concrete piers.

It's a foundation
with three parts,

which you can see here.

A reinforced concrete mat
under the whole building,

then concrete piers,

then wooden pilings
driven down into the mud.

Those wood pilings
are about 80 feet in length.

Underneath the tower,
there are 345 piles alone.

Completed in 1898,
the new ferry building

continues to defy
sinking sand to this day

and anything else
that nature throws at it.

This design has withstood

the earthquakes
of 1906 and 1989,

both of which caused
massive damage

throughout San Francisco.

The building has proven itself

through its innovative
engineering.

At the over
2,000-foot-high Tokyo Skytree,

engineers take Holmes'
revolutionary method

into the 21st century.

To stabilize it, workers
drive 131 concrete piles

into the soft ground.

But the building's
record-breaking height

adds a further problem.

To compensate for this,
Skytree needs a unique system.

Its 75,000 tons of force

is exerted onto
a tripod-shaped base.

160 feet below the surface,

three clusters of 4-foot-thick
walls use friction

with the surrounding soil
to increase horizontal rigidity.

Three 160-foot wall piles
connect each cluster

with added knuckles
acting as spikes,

further increasing friction.

Combined with the column piles,

the towers foundations
act like a tree's roots,

bracing the superstructure

for even the most
extreme of conditions.

But to complete the world's
largest free-standing tower,

engineers must look
to the past...

It's a brilliantly
simple solution

and sparked a renaissance
in skyscraper construction.

...To make
the impossible possible.

Soaring over 2,000 feet,

the Tokyo Skytree is
the tallest free-standing

tower on the planet.

More than six times higher
than London's big Ben

and twice the height
of its predecessor,

the Tokyo tower,

Skytree is changing
the face of Japan's capital.

But as high-rise architect
David Malott reveals,

building to this height
in this highly congested city

poses a unique challenge.

The engineers at Tokyo Skytree
had to put a tower

that's twice as high as
Tokyo tower on a piece of land

that's only a quarter
of that size.

The proportions of
a super-tall tower are crucial.

If a structure is more
that five times higher

than it's narrowest
base dimension,

it can become
unstable in the wind.

But Skytree's ratio
is a daunting nine to one.

It's one thing
to build tall and wide,

and it's a much more
challenging thing

to build tall and slender.

So how do you build a
super slim record-breaking tower

on such a confined plot of land?

Engineers have always been
able to build short and fat,

and after a while,
they mastered tall and fat.

Whoa.

But building tall and
thin has often been a problem.

- Are you sure?
- Go for it.

Ireland's highest round tower
is an amazing feat...

I told you.
Perfect.

...but isn't exactly straight.

Aah!

The first St. mark's campanile
in Venice

certainly looked the part...
Mama Mia.

...But the impact of the weather

and the weight of its five
mighty bells led to disaster.

We're going to need a new tower.

Engineers had to return
to the drawing board.

During the 1920s,

Chicago became synonymous
with skyscrapers.

By the '60s, with space
increasingly at a premium,

developers wanted
to build even higher.

But traditional bulky
construction methods

were stifling their ambition.

However, in 1968,

engineer Fazlur Khan came up
with a game-changing solution.

All right.
Thanks.

And architect Jayshree shah

is here to get
a bird's-eye view of it.

This is the ground-breaking
building

that Khan was working on.

Over 1,100 feet high,

the Hancock center was
the first skyscraper in Chicago

to reach 100 floors.

But this impressive
building sits on

a footprint 27% smaller

than the city's
second-tallest skyscraper

from that time, the chase tower.

So how does the Hancock center
continue to stand

in the face of Chicago's
legendary wind?

Just take a look at this
skyscraper-shaped tower.

If I push on it
just a little bit,

like a lateral force
similar to the wind,

you can see how much it bends.

Now, if I push even more,

you can see how
it begins to twist.

Oh, geez.
All right. I broke it.

But the simple addition

of 45-degree cross braces
changes everything.

You can see
how much stiffer it is.

When I push against
the building now,

it's not bending or twisting
as it did before.

Called braced tubing,

Khan used this technique

to reduce the horizontal loads
on the building.

As the winds pushed
against the building,

their force now transferred
down the diagonals

to the base of the structure,

easing the load on the
building's vertical columns.

Fazlur Khan's braced-tube
design sparked a renaissance

in skyscraper construction.

Engineers at
Tokyo Skytree are drawing

on Fazlur Khan's genius
braced-tube design

to create a record-breaking
super slim structure

that dwarfs the city.

In an area renowned
for typhoons,

building a tower almost double
the height of the Hancock center

on a footprint 51% smaller

requires both brains and brawn.

The 37,000-piece steel framework
consists of three layers

with thousands
of triangular trusses.

Immensely strong,
this steel curtain can resist

wind gusts approaching
250 miles per hour.

As well as defying the odds,

its designers have also created

a shape that makes Skytree
totally unique.

But to brace for
more daunting challenges,

the Skytree team
must turn to the past

and reach for the stars...

It was a beautifully simple
concept that ultimately

helped push our exploration
out into space.

...To produce more
impossible engineering.

At over 2,000 feet,

the Tokyo Skytree is the world's
tallest free-standing tower,

and, with it,
architect Tetsuo Tsuchiya

is redefining Tokyo's skyline.

People can see this tower,
and also we can see the city.

So I think it's a really
great viewpoint

to really understand
the city of Tokyo.

But as high-rise
architect David Malott reveals,

building to this
dramatic height here

means engineers must conquer

a seemingly impossible problem.

Japan is part of what
we call the ring of fire,

so it's one of the most

active seismic zones
in the world.

So earthquakes are a part
of daily life here in Tokyo.

It's a very big challenge
for us to control the swaying

and the movement of this tower.

So the engineers of Skytree

were tasked to build not only

the world's
tallest television tower,

they had to put it in what
is probably the world's

most dangerous location.

In a country that endures

around 1,500 earthquakes a year,

how do you ensure
a super tall tower

will remain standing?

To overcome this challenge,

engineers find inspiration

in an unlikely
innovation from the past.

Launch commenced.

Lift-off.
We have lift-off.

Space historian Amy Shira-Teitel

is in Florida,

at the home of one of history's
most awe-inspiring endeavors.

This rocket is just so big.

It's so great.

Since the 1960s,
Kennedy space center

was the launch pad for NASA's
epic Apollo space missions.

This is really amazing
to be standing here.

This is launch pad 39b.

This is where
the Apollo 10 crew launched

and went all the way to the moon
to orbit before coming home.

At the moment of launch,

the five f1 engines together

produced more power
than 85 hoover dams.

The sound of the launch
was so intense,

they actually had to dump
3 million liters of water

onto the pad every minute
just to dampen the sound waves

so they couldn't bounce back up
and rip the rocket apart.

Just like old times.
It's beautiful out there.

But achieving
such an explosive lift-off

called for a lot of energy.

Almost 530,000 gallons
of rocket propellant

was needed to get
the over 360-foot rocket

off the ground.

Delivering all that fuel

to the rocket
required umbilicals,

masses of cords and wires

running all the way up
the service structure.

Attached to the rocket
by spring-loaded swing arms,

it was essential
the umbilicals remained in place

until the very last second

before an electrical
discharge jerked them

and the swing arms back
towards the launch tower.

However,
the challenge was controlling

the swing arm's
sudden powerful movements.

They had to make sure
they wouldn't break off

from overexertion or bounce back

and hit the rocket
as it left the launch pad.

Thankfully, there was one
engineer working on a solution.

To address this problem,

former air force engineer
Paul Taylor

worked alongside NASA.

His patent for an
innovative shock absorber design

offered a breakthrough
for the Apollo mission's

tricky launch procedure.

The concept Taylor came up with

was the fluid damper,
or the liquid spring,

and it works
something like this.

Now, imagine that
this coffee press

is our fluid damper,

and it's sitting between
the tower and the rocket.

You can see that
when our damper is empty,

it offers very little
resistance to weight

or the force of the swing arm
when it's released.

But if you fill it
full of fluid...

look at the magic
of the green liquid...

and if you put
the weight back on,

you can see it compresses
much more slowly.

So what's happening is,
as the plunger is pressed,

the liquid is forced
through the holes.

This creates resistance,
which dissipates the energy,

which makes the plunger
move more slowly.

During launch,
as the umbilical-laden

swing arms spring back,

the attached fluid dampers
are compressed,

and the fluid
inside them is forced

through holes in the piston.

This action creates friction,

which slows the arms
down to zero speed

at the end of travel

and minimizes risk of damage
to the tower or rocket.

In 1969,
Taylor's ingenious system

proved its worth
as Apollo 10 safety launched

on its pioneering mission
to orbit the moon,

making its mark
in space-travel history.

We are go for a mission
to the moon at this time.

We have ignition sequence start.

All engines running.
Launch commence.

Lift-off.

Taylor's hydraulic innovation
has stood the test of time

and is still in use today,

protecting sensitive equipment

during launches to
the international space station.

It was a beautifully
simple concept that ultimately

helped push our exploration
out into space.

But using fluid dampers to brace
the world's largest tower

against earthquakes is an
altogether different challenge.

To do this,
the Tokyo Skytree team

must make
revolutionary renovations...

...to make
the impossible possible.

The Tokyo Skytree is the tallest

free-standing tower
on the planet.

But at over 2,000 feet,
engineer Atsuo Konishi

and his team must brace it
against a potentially

devastating natural phenomenon.

To stabilize the tower,

engineers rely on fluid dampers

developed during
NASA's Apollo space program

and from something
closer to home.

The engineers first step

in controlling the shake
of the tower

centers around an ancient
earthquake-proof structure

called a Japanese pagoda.

A flexible earthquake-dampening
central pole

called a shinbashira

stabilizes this
tiered wooden structure.

Skytree's engineers
are emulating

this ancient technology,

creating an enormous
1,200-foot concrete column

set on six
giant rubber bearings.

And sandwiched between this mass

and the tower's steel structure

lies the Apollo-inspired
fluid dampers.

Situated between 410
and 1,230 feet,

the series of fluid dampers
control the movement

of the free-standing
11,000-ton concrete core

and the steel exoskeleton
throughout a seismic event.

The different vibration cycles
of the central column

and steel frame can counteract

the vibration
of the entire tower.

The system is so effective,

it reduces an earthquake's
vibration by 50%,

meaning Skytree will survive

Tokyo's most severe
seismic activity,

the likes of which is only
expected once every 1,000 years.

But as well as standing firm
during a magnitude-7 quake,

this state-of-the-art
communications hub

must also continue
to transmit its signals.

And to do this, any vibration
of the 460-foot antenna tower

must be made practically still.

So the team introduces
a secondary vibration system

at the pinnacle of the tower.

The tuned mass damper contains
a 45-ton concrete block

which moves like a pendulum.

During an earthquake,
there is a time lag

between the vibration
of the tower itself

and the movement
of this concrete mass,

canceling out the vibration
of the main structure,

resulting in a super
stable antenna system.

It can still transmit

even during Tokyo's
most extreme seismic activity.

Skytree's
breakthrough engineering

has tamed one of nature's
most devastating forces.

But to complete this
mammoth super-tower,

the design team faces
even more formidable challenges,

and they must draw on another
great innovation from the past

to produce more
impossible engineering.

The Tokyo Skytree
is setting a new benchmark

in high-tower design.

As a communications hub,

the over-2,000-foot tower

can transmit
up to 62 miles away.

But, for its architect,
Tetsuo Tsuchyia,

this engineering colossus stands

for so much more.

But as high-rise architect
David Malott can see,

creating a bird's-eye view
in a tower this high

poses tremendous
technical challenges.

When you're building
observation decks,

it's going to be subjected

to tremendous force
from typhoons.

To offer these
breathtaking views requires

one resilient material... glass.

But how do you ensure the glass

will remain in a safe state

in the face of typhoons
and earthquakes?

This would have been impossible

without a chance discovery
made in Paris

over 100 years ago.

Scientist Suzie Sheehy
is here in Paris to discover

how the city's
notoriously bad traffic

inspired a transformation
of safety

in the modern world.

In 1903, driving was fast

becoming the hot new hobby
among Parisians,

but, like today, the traffic

was congested and dangerous,

and accidents were commonplace.

It sparked an idea

that will go on
to change the world.

Born in 1878, scientist
Edouard Benedictus

studied chemistry in Germany

before setting up
a laboratory in Paris,

where he made his
breakthrough discovery.

Car windscreens were causing
drivers serious injuries

in the case of an accident.

The windscreen would
smash into shards,

which in some cases
proved fatal.

Incredibly, Benedictus
discovered a solution

to this concerning problem
entirely by chance.

During some routine
testing at his lab one day,

Benedictus accidentally knocked
a glass flask off a shelf.

And, remarkably,
instead of smashing

into a thousand
different pieces,

it actually
maintained its shape.

Examining the shattered flask

that had mysteriously
remained in one piece,

Benedictus observed
remnants of a liquid plastic

within the vessel

and concluded
that its thin coating

held the broken glass together.

Benedictus had a brain wave.

He realized that this
plastic-coated glass

had the potential to save lives.

So, this is a piece
of laminated glass,

and it's like
the modern evolution

of Benedictus' discovery.

It's basically just
two pieces of glass

which are bonded together
with a piece of plastic between,

which holds it together.

And over here
I also have some pieces

of just normal sheet glass.

And this is similar to the glass
that would have been used

in a car windscreen
in Benedictus' time.

To see how each one
reacts under impact,

a 4 1/2-pound steel ball

is set 13 feet off the ground.

First up,
the normal sheet of glass.

Ready to go.

Aah!

Wow! Okay.

So this piece of glass
is really smashed.

You can imagine how dangerous

one of those sharp
shards of glass would be

if it came flying at your face

during a car accident.

So, instead, let's try
a piece of laminated glass

and see what happens.
All right.

Place my laminated glass now,

but this time I'm going
to raise it up higher.

With the drop height
raised to 20 feet,

will this laminated
glass withstand impact?

And how will engineers
employ this technology

against the fury
of mother nature?

As the world's tallest
free-standing tower,

the Tokyo Skytree offers
stunning views of the city.

But to create a safe viewpoint
at this dramatic height

that can also
withstand typhoons,

engineers draw
from an early 20th century

breakthrough in glass design.

Let's try a piece
of laminated glass.

To test its strength,
Dr. Suzie Sheehy raises

a 4 1/2-pound steel ball

to a drop height of 20 feet.

Whoa.

It actually didn't go through.

Oh, wow.
Okay.

So my steel ball

managed to form a beautiful

spider web pattern on here.

And the glass has actually
stayed in place,

stuck to the plastic
in the middle.

Benedictus'
layered glass is so resilient

because the lightweight plastic
stretches when struck,

absorbing any force and offering
a tear-resistant barrier.

So it's a pretty
simple invention,

but it's made the roads
a much safer place.

Engineers at Tokyo Skytree

are using Benedictus'
ingenious layered glass

to take on Tokyo's
powerful typhoons.

With two 360-degree
observatories

and one of the highest skywalks
in the world

incorporating a glazed floor,

each of Skytree's
1,027 panels of glass

must be super strong.

Installed from the inside

and integrated into steel
curtain wall framing,

this state-of-the-art
laminated glass

can withstand winds in excess of

a mind-blowing
325 feet per second.

Welcome to Tokyo Skytree
Tembo galleria.

Because of the
pioneering work of Benedictus,

even in the unlikely event
the glass does shatter,

the panes will remain in place,

allowing around
4 1/2 million people a year

to safely experience

one of the greatest
vantage points on the planet.

Completed in 2012,

this audacious
architectural marvel

was constructed
in under four years.

It stands as the result
of ambitious planning

and testing by
thousands of engineers.

By learning from the great
pioneers of the past, adapting,

upscaling, and making
innovations of their own,

engineers have written
a new chapter

in high-rise design.

They have succeeded in
making the impossible...

Possible.

Tokyo Skytree
is a striking landmark.

It's really a combination of

state-of-the-art Japanese
construction technology,

and also the very old
Japanese wisdom

of creating very tall towers.

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