All language subtitles for Impossible Engineering s02e11 Worlds Tallest.eng

Today on Impossible Engineering, the
world's tallest construction, a record

-breaking supertower.

Construction has never been attempted
before at a building this tall in

London. And the tallest bridge on earth.

The deck is about 150 meters above the
Plateau de France.

It took revolutionary engineering.

Look at the crazy amount of glass that
this building uses.

11 ,000 separate pieces.

to make the impossible possible.

London.

Some of the world's most iconic
buildings dominated skyline.

And in 2012, a modern marvel was
constructed, altering the city's look

Meet the Shard.

At 1 ,016 feet tall, this futuristic
skyscraper is the tallest in London.

Wow, look at that.

That's an incredibly audacious piece of
architecture and some very impressive

engineering.

The Shard rises up from the heart of
downtown London.

This jaw -dropping tower is over three
times the height of the Statue of

Liberty. Its facade is made out of a
staggering 11 ,000 glass panels.

That's enough glass to cover 130
basketball courts.

Beneath the 196 -foot spire lies the
spine of the building.

The colossal concrete core supports 72
levels,

totaling over a million square feet of
floor space.

Building these buildings is always
exciting.

You're building up.

taller than anybody's gone in Europe.

But this one was particularly difficult.

The population in London is surging.

It's estimated that the city could reach
10 million inhabitants by 2030.

With limited room to grow, designers of
any new buildings are looking to the

sky.

Finding enough open space to build a
megatower in this bustling city is a

seemingly impossible challenge.

It's smack in the center of London, with
London Bridge Station on one side,

Guy's Hospital Tower on the other, the
Jubilee line of the two passing very

close underneath.

Building the shard on this site would be
impossible without help from a great

innovator from the past.

In the 1950s, the bustling Italian city
of Milan wanted to build a subway.

But engineers needed to figure out a way
to build without disrupting city life.

We've come here to a site where the
metro network is being expanded.

And being here and seeing the scale of
this site, you can imagine the

disruption that would be caused if you
tried to do this in the center of the

city. Really an enormous challenge.

Poor soil conditions make tunneling
beneath the city streets here nearly

impossible. This is actually a really
good illustration of one of the key

problems here in Milan.

You can see how much water is flowing
in. So these are about the worst

conditions you could hope to be digging
tunnels in.

To contend with watery soil, tunnelers
historically used a technique called cut

and cover.

Let's imagine that I want to dig a
trench down between these buildings.

And you can see what happens when I do
that in this sandy soil.

Initially, there's no problem. But if I
push just a little bit too far, you can

see that eventually I destabilize the
soil and my structures will fall into

trench. And obviously that's completely
unacceptable on a site in a congested

urban center.

But engineer Dr.

Christian Bader turned the cut -and
-cover concept on its head.

Instead of building one big trench
initially, he built two little trenches

the sides of the buildings, and into
those trenches he inserted reinforced

concrete walls.

And these then became known as diaphragm
walls.

After dropping in diaphragm walls, Vader
built a roof over the tunnel, allowing

city traffic to resume above.

Digging, tunneling, and construction
could take place without disrupting life

Milan and in cities across the world.

Instead of cut and cover,

Vader's technique covered, then cut.

It's now known as hop down.

Standing down here in one of the new
tunnels of the Milan metro, it simply

wouldn't exist without that construction
technique.

But to speed up construction, engineers
at the Shard take Vader's top -down

method and turn it on its head.

Normally, a building like this would be
built by building a basement first and

digging a big hole down to the bottom
level of the basement and then starting

the core from that lowest level and
building upwards.

Now, we built the core on stilts,
effectively, that held up the core while

were building it upwards, and then we
were... at the same time digging

underneath it and going downwards.

That had never been done before.

It was an innovation for the Shard.

Just 23 piles support the Shard's
concrete core as it rises from a void in

basement level two.

As excavations of the underground floors
continue around the presunt columns,

the core rises, as if balanced on a
tabletop above.

This allowed the engineers to shave
literally months off this project, and

shard was built much more quickly and
much more cheaply than it could

have been.

But huge ambition comes at a price.

The $618 million project required more
than 1 ,400 workers on site.

The flow bit of construction is building
a concrete core that is the real basis

of stability for the structure.

And getting that in place quickly is a
real challenge.

The Shard's concrete core consists of
over 350 ,000 cubic feet of concrete.

Pouring this much concrete would have
been impossible had it not been for a

groundbreaking method developed over 100
years ago.

Minneapolis was known as the flower
capital of the world.

Raw grain was brought here from across
the northern prairie, processed here,

then shipped across the country and
around the world.

But flower production in the 19th
century was dangerous business.

Dry millstones could ignite flower dust,
causing catastrophic explosions inside

wooden silos.

With modern materials, Engineer Charles
Hagelin and grain trader Frank Peavey

designed a safer, stronger silo.

By using concrete in 1908, Hagelin built
the Washburn Crosby Elevator 1, part of

the Washburn A Mill.

At its peak, it could safely produce
almost 2 million pounds of flour a day.

The most innovative thing about wood
design are these 15 cylindrical silos,

measuring about 100 feet tall.

To build the silos, Hagelin developed an
ingenious new method called slip

forming.

So what we've got here is a simple
demonstration of how slip forming works.

I've got this bucket of slightly wet
sand here.

This is going to represent our concrete.

And I've got this other bucket here with
the hole cut in the top. This is going

to represent our slip form.

And here's how the process works.

A little of the concrete goes in.

And slowly, about a few inches every
hour, the slip form gets raised up and

And then I add a little more.

And raised up a little bit higher.

The slip form rig is continually forced
up by hydraulic jack, while concrete is

poured non -stop.

The concrete at the top remains wet and
fluid.

By the time the concrete emerges from
the bottom of the moving mold, it's dry

enough to support the growing structure.

Hagelin's use of slip form construction
revolutionized the way that tall

buildings are constructed.

And today, concrete has become one of
the most widely used materials in

construction, allowing us to build
higher and faster than ever.

At over 800 feet.

The Shard's concrete core is nearly
eight times taller than the Washburn

elevator silos.

Engineers used a supersized version of
Hagelin's slip form rig, measuring 85 by

72 feet.

Thanks to a high -capacity concrete
pump, the system was so efficient, it

reached the 21st floor in just 10 weeks.

It's amazing to think the first 21
stories of this concrete structure went

before they'd even finished the
foundations below.

The concrete core is still sitting on
just 23 piles in the center of the

basement. Engineers need to pour the
rest of the foundation before they can

continue building up the core.

It took 32 hours.

We poured the whole thing in one go, and
it was 5 ,500 cubic meters of concrete.

It was tremendously exciting to see all
that concrete arriving on site.

Built from a central concrete core, the
tower's unique hybrid superstructure is

pulled up around it.

Forty floors constructed of steel, 29
stories of concrete, topped off by a

monumental 23 -story spire at the
pinnacle of the building.

When you're building a tower that's over
300 meters high, one of the real

challenges is getting the people and the
materials up to these incredible

heights when you're doing the
construction.

And the higher the tower gets, the
harder that challenge becomes.

So how do you get enormous amounts of
building material to the top of a mega

tower like the Shard?

The Shard in London is the tallest
building in Western Europe, but getting

materials to the top during its
construction would have been impossible

the innovators of the past.

Heavyweight lifting gained its footing
in the 19th century in an unlikely

Venice, Italy.

It was a time of great change in the
maritime industry, and old wooden

propelled by ore and wind were being
replaced by steel -hulled ships and

big engines.

Traditional manually operated cranes
couldn't handle heavy loads like these.

This seriously compromised the Italian
Navy's boat -building program.

In 1885, British engineer Sir William
Armstrong developed an ingenious

Because of the growing trend of metal
hull construction, the Navy decided to

commission just the thing for the
Arsenale.

And here is the stunning Armstrong
crane.

And the way it works is like this.

This huge boiler would generate enormous
amounts of steam, and that steam would

flow up through the pipework down into
these chambers below.

The steam drove these enormous systems
back and forth, back and forth, and they

in turn helped pressurize the hydraulic
circuit.

Hydraulics allowed the Armstrong crane
to lift what was at the time an

unimaginable 160 -ton load.

It transformed the fortunes of Arsenale.

It opens up a whole new frontier in
crane technology.

Engineers at the Shard took Armstrong's
historic crane design to the next level.

Building this superstructure meant
building some of the tallest, most

tower cranes in the world.

They started with four cranes at ground
level. Those went up to about 160

meters. But above that, we've still got
140 meters of the building to go.

How do we get the structure, the
construction equipment up to that

Engineer John Parker and his team came
up with a radical idea.

Mounting a tower crane to the Shard's
concrete core.

What was unique about the Shard was that
the tower crane was supported on that

slip wall.

Usually you have to fix the crane to the
concrete.

We avoided all that so they could both
go up together.

Installing the Shard Spire required an
even more radical approach.

We then had to use the crane that was
attacked. to the split form to build

another crane which can't leave it off
the main building and allow them to

this final spire on the top of the
structure.

Engineers elevate the tower crane to a
staggering 1 ,040 feet, enabling them to

install the custom -built steel sections
that form the 23 -story spire.

Over 500 tons of steel is installed in
nearly 100 separate lists.

But this isn't the only way the
designers of the Shard are pushing the

architecture.

Its facade is made out of a staggering
11 ,000 glass panels.

That's enough glass to cover 130
basketball courts.

Look at the crazy amount of glass that
this building uses.

It's extraordinary.

It just extends above me in a great big
ribbon of glass up to the sky.

But glass is structurally weak.

So how do you create London's tallest
building out of it?

It would be impossible without an
architectural risk taken 150 years ago.

The Shard in London is the tallest
building in Western Europe.

Comprised of over 11 ,000 pieces of
glass, its bold facade would have been

impossible without an architectural risk
taken 150 years ago.

In the 19th century, as cities like
Liverpool grew ever more dense and space

buildings became smaller, architects
were faced with a real problem.

They had to build upwards, but in doing
so, they had to build thicker and

thicker walls to support the increasing
weight of their structures.

Local architect Peter Ellis came up with
a revolutionary design for his high

-rise building.

This is the Oriel Chambers building.

It contains one of the world's most
important engineering and architectural

blueprints.

That's because the Oriel Chambers
building doesn't need exterior

walls. An iron framework carries the
load of the structure on the inside.

This allowed Ellis to create a facade on
the outside that doesn't have to

support the building.

Ellis' iron frame structure opened up a
whole new world of architectural

possibilities.

Ellis created the glass curtain wall.

The building has 56 road -facing bay
windows over five floors.

The windows flood the interior with
light.

150 years later, the benefits are still
clear.

And to compare it with the building
across the street, where the stone

construction means the windows are very
small, this would have been an amazing

place to work in.

Without Ellis' pioneering use of the
curtain wall concept, The glass -clad

supertowers of today which dominate
cities across the world might not ever

been invented.

It's a real masterpiece of engineering.

Engineers at the Shard are building on
Ellis' glass curtain wall with 13 acres

of glass.

What's incredible is that from outside
the Shard, it looks like it's a

made entirely of glass. But actually,
this glass takes none of the weight.

That's all borne by the steel and the
concrete structure inside.

An incredible piece of engineering.

The Shard's extraordinary superstructure
holds eight sloping facades, defined by

the tower's iconic vertical fractures.

It's often called the shard of glass,
and the idea was to have a beacon here

that would shine out. And this sloping
shape is very good at reflecting the

sunlight and making it shine.

It's a once -in -a -lifetime
achievement.

Also scraping the sky and rising 1 ,000
feet over one of Europe's deepest

valleys. It's higher than the Eiffel
Tower.

It's the tallest bridge on Earth.

It was a very, very big adventure.

Why did engineers take on such a massive
construction?

The small medieval town of Miu lies
directly in the path of the busiest

route between Paris and the
Mediterranean coast.

Miu is not at all adapted to the
motorway traffic.

It could be necessary to have three
hours to cross Miu.

To free MeU from this plague of traffic,
engineer Michel Villajour is attempting

what was previously thought to be
impossible. Build a road high above MeU

the gargantuan Tarn Valley.

The result.

The MeU Viaduct.

The tallest bridge on Earth.

This massive bridge spans a staggering
one and a half miles, towering over 500

feet above the Tarn Valley.

Just seven concrete piers support the 40
,000 -ton steel deck, which is held in

place by a single row of 154 super
-strength cable stays.

Many thought it was impossible to build
that bridge.

We had this very important series of
problems to solve.

Michel had to design a bridge that could
span one of Europe's deepest, widest,

and windiest canyons, using an uneven
valley floor as a foundation.

This would be impossible without help
from the great innovators of the past.

The MiU Viaduct is the tallest bridge on
Earth, but constructing it across one

of Europe's deepest, widest, and
windiest canyons would have been

without strong building materials
developed by a great innovator of the

I'm heading out to the Eddystone, one of
the most treacherous rocks in the

English Channel.

It's a place that arguably marks one of
the most important moments in civil

engineering history.

Eddystone Rock is 14 miles from the busy
port of Plymouth, England.

The rock has sunk countless shifts over
the centuries.

In the 17th century, a lighthouse was
built to warn passing vessels.

A building that can withstand the
elements out here, the pounding of the

day after day and the wind and the rain,
requires a real engineering

achievement.

And engineer John Smeaton had a unique
idea for the Eddystone Lighthouse.

He believed that the sea must give way
to the building, and, unlike earlier

lighthouses made of wood, he built a
lighthouse made of stone.

But it was how Smeaton joined the stones
together that was truly revolutionary,

earning him the title the father of
civil engineering.

Smeaton's original lighthouse stood on
this spot for over 120 years.

And in fact, we can still see the bottom
half of it as that stump of a

lighthouse over there.

Smeaton's structure was so strong, it
was only cracks in the rocks that it sat

on that forced engineers to dismantle
the lighthouse and rebuild it on

Ho.

The secret to Smeaton's success is an
innovative bonding material that can

survive the constant pounding of the
sea.

Smeaton experimented with mixtures of
lime, clay, and iron slag to create

hydraulic lime.

I'm going to try to demonstrate the
innovation that Smeaton accomplished at

tower. Here we have a traditional cob
mortar. This is a mixture of sand and

and straw and lime and a bit of earth.

And these types of mortars were used
traditionally for many hundreds and

thousands of years.

And the other material that I have here
is Smeaton's mixture.

Luke places Smeaton's hydraulic lime
inside a cardboard tube, then places the

tube in water.

And then I'm also going to do the same
with the traditional earth mixture.

Got both tubes now filled with the
mortar.

We're going to go away for about a half
an hour, and then we're going to come

back, and hopefully we'll see a pretty
dramatic difference in terms of how

they've performed.

First, we're going to look at the tube
that's filled with the traditional mud

mortar. We're going to see exactly how
much it's set.

And you can see absolutely nothing.

This is the one we're much more
interested in. This is the one with the

that's based on the hydraulic lime
technology that Smeaton came up with.

I can immediately feel that this one is
much more solid. I squeeze it, nothing

happens. If I have a look inside, I can
actually see this now is very, very

solid.

That combination of setting very quickly
and setting underwater completely

revolutionized civil engineering.

What Smeaton had created was the
precursor to Portland cement.

Portland cement's the key ingredient in
all modern concrete.

The engineers at the MeU Viaduct are
using John Smeaton's hydraulic line

technology on an epic scale.

All the piers represent something like
90 ,000 cubic meters or more than 200

,000 tons of concrete.

And this is the concrete which is of
very high strength.

Engineers built each of the seven piers
in 13 -foot sections using a state -of

-the -art self -climbing frame. A
hydraulic -driven system pushed the

reinforced concrete mold upwards in
stages.

One of the big problems, of course, was
to lift concrete because this pier, this

one, is 245 meters high.

Cranes lift buckets of concrete, which
is then poured into the concrete mold.

After each pour is set, the mold is
dismantled.

The frame carrying the mold is then
mechanically pushed by the hydraulic

up the pier and re -anchored in the set
concrete.

The mold is then reassembled for the
next pour.

Each cycle takes about three days.

The piers are completed in just over two
years.

Developing solutions to erect the seven
piers at the same time, it was a very,

very big adventure.

With the bridge pierce complete, Michel
is ready to tackle his next challenge.

Construct MeU's one and a half mile long
bridge deck, long enough to span the

vast Tarn Valley.

The staggering height of the bridge
makes this a unique challenge.

The great enemy of the design of the
bridge is the wind.

The deck.

It's about 150 meters above the Plateau
de France, and so this means that we

have rather high winds.

How do you make the world's tallest
bridge stable enough to handle the

-force winds high above the town of Miu?

Designers look to an ingenious
innovation made by a British civil

half a century ago.

All right, now this is what I'm talking
about.

A vertigo -inducing 135 meters below me
lies the Severn Bridge.

The Severn Bridge provides a vital link
between England and South Wales.

Lying inland from the Atlantic Ocean,
the River Severn begins where the

Channel ends.

The high ground of Exmoor on the South
Shore and the mountains of Wales on the

North create a funnel for the prevailing
westerly winds and Atlantic storms,

increasing their power.

Civil Engineer Sir Gilbert Roberts was
the man tasked with building a bridge

across the River Severn.

He investigated how aerodynamic objects
handled strong winds, which led him to a

truly groundbreaking idea for a bridge.

So what I have here is a model airplane,
and you can imagine that the wing of

this airplane is representing the bridge
deck. So a wing has a curved surface on

the top and it has a flat surface on the
bottom, and this means that air passing

over the wing has to travel further
across the top than on the bottom.

As air passes over the curved surface,
it speeds up and loses pressure.

The pressure of the air below remains
high and pushes up towards the low

pressure area, creating lift.

There we have our starting weight, 45
grams.

What I'm going to attempt to show you is
with this hairdryer to generate some

wind.

Right, so there we go.

The engineers here didn't want that to
happen to the bridge deck.

But when Luke flips the airplane over,
the lift effect is reversed, creating a

downward force.

You can actually see the downward force
that's coming from the wind, and that

holds everything nice and taut and safe
in very strong winds.

Now that the curved surface is
underneath, air loses pressure as it

and the high pressure above presses
down.

And, of course, this is exactly the
principle that the engineers used on the

Severn Bridge.

With this breakthrough, Sir Gilbert
Roberts and his team created an

steel box girder deck.

The first of its kind in the world.

Engineers at the MiU viaduct have
created a bridge deck that's over 3 ,000

longer than the Severn bridge deck and
weighs a colossal 40 ,000 tons.

It has a continuous shape, very, very
limited inclination, helps the wind

passing. below and reduces automatically
the wind forces.

To build MiU's colossal steel deck,
engineers had to assemble it in pieces

a gigantic steel jigsaw puzzle.

The pieces were cut in factories all
across France before being transported

MiU.

Core, which could be the spine of the
bridge, has been assembled in segments

20 meters and brought with trucks to the
side.

The extreme height of the piers rule out
using a crane.

The only option for engineers is to try
to slide the two massive sections of

deck together from each side of the
valley.

The piers are so slender that classical
launching techniques would have been

very critical.

It would not have been possible.

The leading edge of the deck weighs 7
,700 tons.

The pier's great height to width ratio
means they're susceptible to lateral

forces. Pushing the deck across the
pier's surface will create friction,

increasing the lateral force with
potentially disastrous consequences.

Reducing friction on this scale would be
impossible without help from an

accidental innovation from the past.

The Minou Viaduct in France is the
tallest bridge on Earth.

To construct it, engineers had to build
the road deck from each side of the

valley and meet in the middle without
causing friction, which would collapse

bridge. This would have been impossible
without an accidental innovation from

the past.

In 1938, an American chemist... Roy
Plunkett was experimenting with the gas,

tetrafluoroethylene, when it
unexpectedly solidified, coating the

test tube with a waxy resin.

Called polytetrafluoroethylene, or PTFE,
Plunkett had created what would

eventually become Teflon.

It has lots of different properties.

It's very corrosion resistant.

It's chemically inert. It doesn't react
with other materials.

And it has a very high melting
temperature.

But above all of these, it's very, very
slippery.

And being slippery means that Teflon is
a great tool for overcoming the forces

of friction.

Something that's hard to do with a
standard metal.

So here I have a sled connected to a
metal tray underneath and about 45 kilos

bricks and sand.

As I start to pull against this now, you
can see I've got 5 kilograms and I've

still got no movement. So that's the
friction preventing my sled from moving.

I'm up to 7 kilograms, 10 kilograms, 11,
12,

and there it goes.

So that's about 120 newtons of force to
pull those along.

Next, Andrew uses a metal sheet coated
with PTFE.

So let's give it a go.

I've got 2 kilograms, 5, 6, 7, and look,
it's starting to move already.

7 kilograms here to overcome the
friction.

And you compare that to 12 kilograms,
that's 120 newtons. That's about 50

newtons difference to move the same
amount of weight.

PPFE is made of carbon and fluorine
atoms.

Fluorine has a high electronegativity,
meaning it repels other atoms.

The fluorine wraps around the carbon,
preventing the carbon from reacting to

outside forces.

Slippery substance.

Engineers at the MiU Viaduct are using
PTFE in a unique mechanism that will

launch the massive bridge deck across
the Tarn Valley.

Call the translator.

The machine uses the slipperiness of
PTFE and hydraulic jacks to lift the

off each pier entirely before moving it
deeper into the valley.

Each translator uses two wedge -shaped
blocks coated in PTFE. A hydraulic ram

pulls the upper wedge, which slides it
up the lower wedge.

This lifts the deck away from the pier,
pushing it forward at the same time.

The lower wedge then slides backwards,
lowering the deck back onto the pier.

Each cycle moves the deck approximately
two feet.

All the launching systems are moving in
the same time, by the same distance.

And so you can understand very clearly
that it's not producing any force in the

pier.

15 months after starting, the two
sections of deck meet above the Tarn

This system was really the key of the
success.

But supporting 40 ,000 tons is no small
feat.

Additionally, unstable limestone in the
region ruled out a suspension bridge,

which relies on firm anchor points at
each end to take the weight of the deck.

So for Michel, there was only one
alternative.

I wanted to design a cable state bridge
because cables are very strong.

They allow to make very, very modern
structures.

Constructing a multi -span cable -stayed
bridge on such a huge scale would be

impossible without groundbreaking work
from over 60 years ago.

The MiU Viaduct is the tallest bridge on
Earth, but supporting its 40 ,000 -ton

steel deck. by a single row of 154 table
stays would be impossible without the

innovation done by a German engineer
over 60 years ago.

Franz Dissinger helped rebuild Europe
after World War II.

With some 15 ,000 bridges in need of
repair, Dissinger's construction

were both cost -effective and efficient.

What Dissinger built was this, the
Stromson bridge.

A cable state design that has since been
recognized as a landmark in engineering

history.

This cable state support system in
Stromson, Sweden is simple but very

effective.

Imagine... My arms are cantilevering out
from my body like this. And I'm trying

to hold the buckets of water in place
like this.

I need to do a lot of work with my arms.

This is not exactly easy to hold on to.

I'm going to use this rope here to
represent the stay cables attached to

bridge deck.

And I'm going to pull that over my head,
which is representing the piers.

So now the majority of the weight is no
longer carried by my arms, but through

the cables onto my head and down to the
ground.

And that is exactly what is going on
behind us.

The weight from the bridge and the loads
from traffic are being transferred

through the cables and down onto the
piers.

Engineers at MIU have taken Dissinger's
method to the next level, creating a

structural masterpiece.

The origin of this bridge is a cable set
bridge, but with multiple spans. This

is really very special.

Dissinger's Stromson bridge has only one
central span.

The massive Miu Viaduct, 6.

After a little more than three years of
construction, the integrity of the

bridge can now be tested.

28 trucks, weighing a total of 900 tons,
are driven en masse to the center.

The deck flexes, but only a few inches.

The bridge remains firm.

Today, I'm, of course, extremely proud
because there are many steps in erecting

a bridge like this.

Finally, when the bridge was completed,
it was an enormous success.

For engineer Michel Villajour, it
represents the achievement of a

You know, when you have past years
working and fighting for a bridge, you

and that suddenly it's finished.

There is really a moment where you don't
know what to do.

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

innovations of their own.

Engineers of the Shard and the MiU
Viaduct have made the world's tallest

structure.

They've made the impossible possible.

Repair and Synchronization by
Easy Subtitles Synchronizer 1.0.0.0