All language subtitles for Impossible Engineering s02e03 Ultimate Football Stadium.eng

Today on Impossible Engineering, a
football stadium of record -breaking

proportions.

Every day I walk around and I'm just
marveled by the feat that this building

actually is.

One of the largest dome structures in
the world.

It's the longest continuous single arch
span in the world and really an

incredible engineering feat.

It took revolutionary engineering. The
roof structure itself.

is equivalent to the weight of 99 Boeing
777s. To make the

impossible possible.

The Dallas Cowboys is one of the most
popular football teams in the NFL,

them the nickname America's Team.

And in 2009, America's Team decided it
was time for a new home.

The idea from the very beginning was
really to create the finest stadium of

kind anywhere on the planet.

Architect Brian Truby was asked to build
the largest dome structure in the

world.

The engineering in the project was for
us a particularly unique challenge.

What Brian created is a structural
masterpiece.

The epic AT &T Stadium.

AT &T Stadium can host a jaw -dropping
105 ,000 fans.

The massive structure is almost 1 ,300
feet long, with the world's largest

sliding glass doors on each end.

The building spine is two of the longest
unsupported arches on the planet.

They support a state -of -the -art roof
that can be opened and closed at will.

But this $1 .2 billion stadium is much
more than a football field.

We knew from the beginning that the
Dallas Cowboys would only be here 10

year. So we needed to make sure that
this building would be alive and living

the remainder of the year.

Texas summers are brutal.

The stadium's 104 million cubic feet of
interior space needs to be cool and

comfortable year -round.

The first step towards achieving this? A
gigantic roof.

The roof structure itself.

is equivalent to the weight of 99 Boeing
777s.

Building a roof over a football stadium
is no easy feat.

One of the incredible challenges with
this venue is creating that large column

of free space.

The huge forces.

that come into play to keep 104 million
cubic feet column free are enormous.

So how do you hold up one of the largest
single -span roofs in the world without

any support?

Since the dawn of time, engineers have
struggled to hold things up.

The Temple of Artemis was one of the
seven wonders of the ancient world.

But its vast roof needed over 100
columns to

stop it from caving in.

The Romans took a lightweight approach.
The Colosseum's huge ring of awnings

protected spectators.

But sadly, not those that are staying.

The solution for AT &T Stadium comes
from the 19th century Portuguese city of

Porto.

In 1875, engineers were building a new
rail line between Lisbon and Porto. But

when they arrived here on the banks of
the Douro River, their progress ground

a halt.

At the time, a span of this size was
considered extremely challenging.

And so a bold and innovative new
approach to bridge design was required.

French engineer Gustave Eiffel was up
for the challenge.

Now, the challenges that Eiffel faced in
building this span were just immense.

In addition to the width of the span,
the river is also very fast flowing.

up to 20 meters deep in flood season,
and this meant that it was impossible to

put piers in the water.

With no obvious way to support the
bridge, Eiffel proposed an audacious

solution. An enormous single arch built
into the sides of the riverbank.

An arch on this scale seemed an
impossible task.

But Eiffel proved everyone wrong.

And this is the result of his
achievement.

Isn't it an exquisite example of
engineering?

In order to make this a reality,
however, Eiffel had to completely

design.

Now, for bridges, the arch is actually a
really brilliant shape, but it does

have its limits, and I can illustrate
that using this piece of card.

If I place this card between two stones
that represent the bridge abutments, and

I place a load on it, it supports that
load using compression, and the

compression flows down through the arch
and into the abutments.

But, of course, in a location like we
have here, where we need a much larger

span, we have to increase the length of
our span, and our arch becomes much more

shallow. And then the forces of tension
start to take over. And as my structure

is loaded, you can see that it struggles
to support that load. And this was

precisely the problem that Eiffel faced
here at the Douro.

Luke is heading into the heart of Gustav
Eiffel's solution.

So here I am dangling halfway up of
Eiffel's magnificent arch structure. And

have to say, it's a real privilege to be
able to do this.

By making use of a simple system of
triangles, Eiffel was able to create a

structure that was both light and very
strong and stable, and had a bigger span

than ever before. And it's a real marvel
of engineering.

Simply genius.

So to understand how this truss system
works, we can make a simple comparison

between two shapes that are commonly
found in engineering.

If we look first at the square, you can
see that if I push down on it, it

doesn't take long until that square
deforms. and collapses.

And that's because the square lacks
inherent stability and rigidity.

But you can see if I take this triangle
and I apply a vertical load to it, you

can see that it's able to take that
load. And that's because these two side

elements go into compression, this
bottom element goes into tension, and

equilibrium created at the point where
I'm applying the load.

By exploiting simple physics.

Eiffel left his mark on engineering
history when his bridge spanned the

distance of its age.

Eiffel's experiences here ultimately
provided him with the engineering

and technique to go on to create his
most famous structure, the Eiffel Tower.

Not only that, but in creating this, he
helped to completely redefine arch

construction. And today, arches form
critical parts of some of the most

impressive and iconic structures all
around the world.

The designers of AT &T Stadium are using
Eiffel's innovative arch truss design

in record -breaking proportions.

It's the longest continuous single arch
span in the world.

So we're really taking inspiration from
some of the bridge structures that are

out there and applying it to the
building.

So what you're looking at are two
primary arches.

that span about 1 ,400 feet each. The
size of the trusses themselves, they're

about 14 feet wide by about 35 feet
tall.

The weather in Texas is beautiful during
football season, so the owners want one

of the largest dome roofs in the world
to also be retractable.

It's not natural for a retractable
structure to be on top of that. It

very steep slope.

A seemingly impossible challenge.

In Arlington, Texas, engineers have
created one of the largest sports and

entertainment venues on earth.

For architect Brian Truby, the stadium
has changed the face of arena design.

From an engineering standpoint, there's
really very few structures like this.

What you see here really is the most
transparent stadium in the world. And

can see the arches, for instance, that
span the entire length of the building,

about a quarter mile.

The stadium's twin arches soar over 300
feet above the playing field.

Each one weighs over 3 ,000 tons,
distributing 19 million pounds of thrust

four colossal concrete abutments.

The concrete abutment then, what you see
above ground, takes all those forces

directly into a large concrete footing
below ground. It's about four times

larger than what you see above ground.

Each concrete abutment requires over 350
,000 cubic feet of concrete.

Work began on the stadium's massive dome
roof in July 2007.

They basically would start at the
abutments on each end, and they would

with a single truss, and they would
build towards the center.

Six shoring towers are erected to
temporarily support each truss section

they're moved into position.

When the connecting keystone piece is
added, not even a single column is

to support the stadium's dome roof.

Placing that keystone piece in the
truss, that's really the first time

that that the structure's allowed to
load on itself.

With the steel truss arches in place,
engineers can begin work on the

massive dome roof.

So the roof itself actually covers about
660 ,000 square feet. And

the reason for the shape of the roof
tracks back to Texas Stadium.

Texas Stadium is the former home of the
Dallas Cowboys.

It's renowned for its open roof design.

The iconic hole in the roof is very
signature to us.

The owners of the new stadium want to
incorporate that same open design

but with the ability to close the roof
in bad weather, a seemingly impossible

challenge.

One of the largest challenges that we
had is that arch shape of the roof

structure below.

It's not natural for a retractable
structure to be on top of that. It

very steep slope, particularly when you
get to the ends.

At the very steepest level, we're at a
23 -degree angle, which is really the

steepest retractable roof that's ever
been done.

How do you move an 837 -ton roof panel
up and down such a steep incline?

It's a task that would be impossible had
it not been for a high -altitude

innovation made over 150 years ago.

Architectural historian Jen Massengarb
is in the White Mountain National Forest

in New Hampshire.

She's looking for an invention many
believed couldn't be built.

With an elevation of 6 ,288 feet above
sea level, more than 1 ,900 meters,

Mount Washington has long been the site
of exploration since the late 18th

century. But it's got bad weather and
rough terrain and an incredibly steep

grade, and so only the most adventurous
climbers were able to make it to the

summit to see the stunning views.

Sylvester Marsh was a successful
businessman in the meatpacking industry.

But it was his passion for hiking that
led him to his biggest achievement.

After getting trapped on Mount
Washington in a storm, he decided to

railroad so tourists could visit the top
of the mountain.

The basic problem Marsh faced, of
course, is that this grade is simply too

for a regular railway.

In a typical car, the wheels would have
spawned without any friction, and the

train would have slid right back down
the mountain.

To overcome the extreme gradient.

Marsh built a train that can literally
grip the track.

When it opened in 1869, the Mount
Washington Cog Railway was an

marvel of its day.

It travels a total of about three miles,
2 ,700 feet at the base, and we're

headed up there, 6 ,288 feet above sea
level, making it the second steepest

mountain cog railway anywhere in the
world.

The secret to how it works lies in an
incredibly effective system known as

and pinion.

Here's a simple demonstration about how
this rack and pinion system works.

If we imagine for a moment that this
plank of wood is the side of the

and I'm the train, I'm obviously going
to try to get up the mountain, and you

can see that I slide back down.

However, if we apply a rack to the side
of the mountain,

And I'm still the train. My feet act as
these pinions in the rack. And you can

see that I can easily climb off the
side.

The pinion is a toothed cogwheel
positioned centrally on the underside of

railroad car.

The pinion engages with a rack, which
lies between the track's running rails.

You can hear the pinion. and engaging
into the rack, providing that extra

connection and the friction that's
needed to overcome this steep grade.

And in fact, we're now on the steepest
part of the track, called Jacob Bladder.

There's a whopping 37 % grade here. And
in fact, the difference in height

between the front of this carriage and
the back of this carriage is about 13

feet.

Marsh's engineering genius didn't end
there.

To safeguard the train from rolling
backwards, the pinion engages with a

brake so the cog can only move in one
direction.

If the train starts to slide down the
mountain, the ratchet will automatically

drop, locking the wheel in place.

Marsha's design was an engineering
marvel.

When it opened on July 3, 1869, tourists
flocked to take the train and come up

to the top of this mountain and enjoy
this incredible vista.

And in fact, Marsh's design became the
blueprint for other Cog Mountain

across Europe and around the world.

Engineers at AT &T Stadium in Texas are
using Marsh's rack and pinion system on

an epic scale.

A cutting -edge track guides 1 ,600
-pound panels up and down the stadium's

steep -inclined roof.

One of the challenges with a retractable
roof on a domed surface is, of course,

the curvature.

So each of the panels, as they move then
down the tracks, they travel about 100

feet vertically.

Over 1 ,300 feet of mechanized railing
is installed on the stadium's arches.

The amount of engineering that went into
this was really massive.

You know, you have structural electrical
mechanization.

The 65 ,000 square foot retractable roof
panels move using this rack and pinion

system.

You can see the rack here, and then the
gear pin here will interlock with this,

so it's an extremely robust connection
that very directly connects the roof to

the retractable portion.

The gigantic roof needs surprisingly
little power to open and close.

The retractable roof is powered by a
series of 7 .5 horsepower motors.

Each side is powered by 64, so it's
roughly a Corvette engine pulling and

pushing the roof as it moves along.

The motors need to generate almost 1
,000 horsepower to close the roof.

To open the roof, the motors act as a
braking system.

There's a lot of energy generated as
they move back down because of the

of the panels themselves.

When combined with the world's largest
lighting glass doors, this awesome

structure offers a unique open -air
experience.

When everything is open, you really have
almost an outdoor experience that you

would get in an outdoor venue.

I think that flexibility and that
uniqueness is what sets the stadium

But to keep such an open venue
comfortable in this sweltering Texas

stadium needs a supersized climate
control system.

80 ,000 -plus fans generating heat.
You've got all the technology, including

video and sports lights. All those
things create a particular challenge.

In Arlington, Texas, engineers have
created a modern marvel.

This building is about 3 million square
feet.

The largest stadium built to date is
about 2 million square feet, so we're a

third larger.

With a gigantic retractable roof and the
world's largest sliding glass doors,

the structure literally embraces the
element.

But to succeed as a year -round venue,
the stadium needs a cutting -edge

control system.

We really felt like our fans deserved a
venue that would be able to be climate

controlled, and mainly for the heat,
because it gets really hot down here in

Texas.

Keeping all 105 ,000 spectators
comfortable is a huge engineering

There were two big influences.

External heat hitting the building and
heating it up. And you've got 80 ,000

plus fans generating heat. You've got
all the technology, including video and

sports lights.

All those things create a particular
challenge.

So how do you keep such a vast stadium
cool?

Designers look to the great innovators
of the past for the answer.

Man has strived to keep cool for
centuries.

Roman Emperor Various Avitus demanded
mountain snow be brought to his garden

during the summer to make the most of
the natural breezes.

But his comfort was short -lived.

In 2nd century China, inventor Ding Wan
created a mechanical fan system to

provide the perfect temperature for a
room full of people.

Except that is for the unfortunate
operator.

In the early 20th century, a problem
facing the print industry inspired what

would become the first air conditioner.

In 1901, a young engineer called Willis
Carrier was summoned to a publishing

company with a problem.

Because the facts had printed in colour,
the paper had to go through the presses

multiple times to build up those
different layers of ink.

But because of the heat and the
humidity, the paper would swell and

time it was put through, and that would
mean the colours ended up not being

aligned, ruining the print.

25 -year -old Willis Carrier had a
simple but very effective solution.

Physicist Andrew Steele is heading into
an artificial jungle to put Carrier's

concept to the test.

Now, it's not especially hot in here,
but it's very humid, above 90%.

Here we have a modern reimagining of
Carrier's invention.

We've got a nice big fan here on the
back, and on the front we've got this

spiral of copper tubing.

So what we're going to do is pump some
cold water through that copper tube.

We're going to suck the hot, humid air
from all around us in through the back

the fan.

And as if it wasn't enough of a
challenge taking on the jungle, we've

this kettle back here, which, when it
starts to boil, is going to produce a

of steam.

Down here we have our reservoir of nice
cold water. It's full of ice packs.

And inside here we've got the pump.

So what I'm going to do is just start
the pump up.

And over here, just switch on the fan.

And you can see this hot, steamy, humid
air is being sucked through the fan.

As the water vapor in the humid air hits
the cold pipes, it condenses, turning

it into a liquid state.

And even though it's only been on a very
short period of time, it's already

sucked all this water, this humidity,
out of the air.

Willis Carrier's method to reduce
humidity at the publishing company had a

welcome side effect.

And on this side, it's actually quite
pleasant. It's lovely, it's cool, and

very dry.

The modern air conditioner was born.

Factories and hospitals were transformed
by this technology.

And in 1922, the advent of a centrifugal
chiller allowed entire buildings and

department stores to enjoy the comfort
of Carrier's invention.

Today, air conditioning units are
completely ubiquitous.

They allow us to control ventilation, to
clean air, to dehumidify, and most

importantly, to control its temperature.

Willis Carrier's invention truly has
made the impossible possible.

Engineers in Texas are using Carrier's
groundbreaking invention on a staggering

scale.

What you'll see as you look across the
top of the upper bowl are huge ducts.

Many of these ducts are about six feet
in diameter, so you can actually walk

through the middle of them.

The system can throw out 11 ,000 tons of
cooling capacity, but that's not

enough. To keep spectators comfortable
in this vast open space, designers will

need to take advantage of the laws of
physics.

is one of the largest dome structures in
the world.

It truly is a one -of -a -kind venue and
really an incredible engineering feat.

Keeping all 105 ,000 spectators
comfortable is no easy feat. To get the

done, engineers are taking advantage of
the laws of physics.

What they're doing is delivering a
curtain of air that washes down.

over the surface of the seating bowl. So
we're really not air conditioning all

104 million cubic feet.

We're actually air conditioning a zone
about 10 to 12 feet tall.

This downward flow of cool air blankets
spectators. It remains in place because

of its density.

Cold molecules are packed close
together, increasing their weight.

Low -density hot air rises, accumulating
in the vast space in the dome roof.

The size of the interior is one of our
key physical properties that allows us

separate the cooled air from the heated
air and keep the seating bowl cool.

But to truly be a multi -use venue.

Engineers need a surface that can suit a
variety of needs,

not just football.

We knew that it needed to be a venue
that would not just house the Dallas

Cowboys. We wanted to be able to be
flexible so that we could move our field

to grass or grass to concrete or
concrete to wood.

Engineers are seeking inspiration from a
structural masterpiece of the past.

Civil engineer Alfred Castillo, Jr.

is exploring an engineering icon that's
been closed to the public almost 10

years.

Wow. This is incredible.

Opened in 1965, the Houston Astrodome
redefined sports architecture.

Prior to the Astrodome, stadiums here in
Texas, they were built completely open

to the elements.

But coming to a baseball game in the
middle of a Texan summer isn't exactly a

great deal of fun.

Developer Roy Hoffines was moved to
build a stadium after his young daughter

complained of the heat and mosquitoes
when they attended baseball games

together.

The result was a $35 million stadium
that could comfortably house the Houston

Astros away from the glare of the Texan
sun.

It was the world's largest indoor arena
with a circumference of nearly half a

mile. At 350 ,000 square feet, it made
it the largest air -conditioned room on

Earth.

A small but significant problem was
discovered when it opened.

Players used to complain that the lucite
in the dome roof would reflect light,

and therefore making it virtually
impossible for them to catch a fly ball.

Some of the panels were painted white,
but then that led to another problem.

The stadium grass started turning brown
and eventually died.

The stadium needed a solution fast.

Two American engineers, James Faria and
Robert Wright, had the answer.

The pair developed chemgrass, a
synthetic turf consisting of a carpet of

grass blades stretched across a thin
rubber base.

After a trial at a Rhode Island school,
the innovative product was rolled out at

the Astrodome.

And in 1966, the Houston Astros played
their first ballgame on a fully

artificial field that, in honor of the
stadium, it was renamed AstroTurf.

This ingenious invention provided a
resilient playing surface for nearly 40

years. Its portability allowed the
Astrodome to host anything from

racing.

AstroTurf changed sports architecture
around the world.

And the Astrodome provided the blueprint
for an indoor multi -purpose venue.

You can fit three Astrodomes inside
Arlington's mighty stadium.

You know, it's about 120 ,000 square
feet of surface area, and it's really

stage.

What you see here is the result of 30 or
40 years of technological advance and

creates really the finest playing
surface.

To make the stadium's football field,
The massive concrete substructure

over 100 ,000 square feet of state -of
-the -art synthetic turf.

Synthetic turf really rolls up just like
Carthage,

rolls back out, takes about 10 hours.

We've had this surface for the Dallas
Cowboys. We have a completely different

field for college football.

We've had grass in here for soccer, and
we have had basketball here as well.

I certainly think the multi -use aspect
of it will be one of the legacies of the

stadium.

But to create a venue that will truly
leave its mark on history, engineers

turn to a great innovation from the
past.

It was here, at Wimbledon, that the
BBC's first live broadcast of a sporting

event would take place.

And install one of the largest video
boards.

AT &T Stadium is an engineering marvel,
one of the largest dome structures in

the world. It can house over 105 ,000
spectators.

This building has really changed the way
these buildings are perceived.

But to fill all those seats, the stadium
needs an unrivaled viewing experience.

For us, our biggest competition is not
the team on the other side of the ball.

It's network television.

You can set up one of the finest TV
surround sound high -tech environments

your own house.

So what we had to do here was be better
than that.

How do you make every seat the best seat
in the house?

It would be impossible without one of
the 20th century's greatest innovations.

London's Alexandra Palace, an iconic
building that was at one time the center

an engineering phenomenon.

At the beginning of the 1930s, the race
was on amongst some of the world's

finest minds to develop the first
universal, standardized broadcast

system.

Scotsman John Logie Baird had already
created a mechanical method of

transmitting a moving image.

And in the U .S., Philo Farnsworth had
developed a rudimentary electronic

version.

Engineers were determined to build on
those pioneering inventions.

Leading the charge in the UK was a team
of British scientists led by the Russian

Isaac Schoenberg.

Hard at work here at Alexandra Palace.

At the same time broadcast television
was being developed, engineers were

building the very first cameras.

The basis for recording any image is
capturing light.

And what we've got here is a simple
model of a camera. So we've got a big

box and we've got this hole in the
front. Let's go around and have a look,

what we can see.

Well, actually, right now, not very much
because that hole is so big that all

the light is bouncing off the objects in
front of the camera, not really ending

up anywhere in particular on the screen.
We've just got a wash of light.

So what we need then is a lens. And as
our lens, I'm going to be using this

magnifying glass. So if now we pop that.

There we go, on the front of the camera.

I can actually bring the scene in front
of the camera into focus.

The ability to record a moving image
onto film was achieved by the late

but transmitting an image so it can be
viewed in another location is a much

greater challenge.

Russian engineer Vladimir Zvordkin
provided a starting point in 1931.

He patented a camera tube known as the
iconoscope.

Within the tube, a captured image was
projected onto a mosaic of light

-sensitive material, breaking it into
thousands of picture elements known as

pixels. A sweeping electron beam charged
the pixels before they were fed out of

the camera.

Zvorkin's invention allowed us to turn a
picture into an electrical signal, but

it was how that moving image was
transmitted and then replicated on a

the other end that's the really
incredible part.

Schoenberg's team built on Zvorkin's
technology, creating the Emetron, the

British broadcasting company's first
industry standard camera.

By 1937, it was possible to broadcast
live into people's homes.

It was here, at Wimbledon, that the
BBC's first live broadcast of a sporting

event would take place, with the men's
final being beamed into homes across

London. And the hefty young man from
across the Atlantic defeated the good

-looking Continental 6 -3, 6 -4, 6 -2.

The key to transmitting a television
picture is in how the images are

from the camera.

So imagine this is a single still image
of a tennis champion. It's a bit hard to

believe in this case, I know.

What happens is that inside the camera,
that image is scanned into individual

lines, broken down like this.

And then these lines are taken out of
the camera up to the transmitter,

transmitted through radio waves, which
are picked up by the aerial on top of

your home.

Then they're brought down into your
television, where these lines are

reassembled again into a full image.

And obviously, this has to happen very
quickly.

Oh, there we go.

Schoenberg's Emetron camera system used
405 lines, what was then considered high

definition.

I'm not sure I can manage that many.

But that's just a single frame.

To create a moving image... TVs need to
do this at least 24 times every second,

fast enough for the image to appear to
be moving.

The illusion of movement is much the
same as you get with a flick book.

By looking at a number of still images
in very quick succession, you get the

illusion of movement.

Transmitted through Alexandra Palace's
television tower.

Broadcast like the Wimbledon final
marked the arrival of one of history's

greatest innovation.

It's hard to imagine the modern world
without television.

From transmitting breaking news around
the world to covering major sporting

events, TV is now central to the way we
communicate and are entertained.

And without it, the world would be a
very different place.

Engineers in Texas are redefining live
broadcast using one of the largest video

boards.

There's about 10 .5 million LEDs. That's
about 26 ,000 square

feet of video surface.

It's really unparalleled in major
stadia.

It doesn't matter where your seat is.
There is always an unbelievable view.

You don't feel like you are in the upper
deck. You feel like you are a part of

the action, that you can see the passion
and the inspiration on the

participants' faces.

The Colossal Television poses an
enormous challenge for engineer Guy

The structure is 72 feet tall and 160
feet wide.

That's 1 .3 million pounds.

That's a weight of 40 airplanes.

It's so massive, it has to be suspended
from the building's main arch trusses.

So here we are on basically level 10 of
the video board.

We're about 170 feet off of the ground.

We have the main arch trusses, which are
spanning the nearly quarter -mile span.

And then we have these box trusses,
which are there to provide support to

video board.

These monumental arches are once again
providing a critical engineering

for this extraordinary building.

When we were all out here and they
hoisted that board up, everyone was

at the roof wondering, did it sag?

That's such a feat to marvel over and to
appreciate just how complicated the

engineering was.

Three, two.

Since opening its doors in 2009, AT &T
Stadium has hosted over 10 million

visitors.

The first thing people do when they walk
in, they walk in and they go, oh wow.

It's really fun to watch people's
reactions.

For architect Brian Truby, it's been a
life -changing experience.

Seeing the building perform.

is one of the most gratifying things in
my career.

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

innovations of their own, engineers have
changed the face of stadium design.

This venue proves that if you have huge
aspirational goals, you can actually

attain something that's never been
attained before.

and have made the seemingly impossible
possible.

You know, every day I walk around and
I'm just marveled by the feat that this

building actually is.

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