All language subtitles for How.Did.They.Build.That.S03E08.Subways.and.Sightlines.1080p.HULU.WEB-DL.AAC2.0.H264-WhiteHat_track3_[eng]

[Jay Ellis] What happens
when an architect

who's never
designed a skyscraper

lets her imagination run wild?

[Sean Linnane] How the heck do
you build 80-some floor plates,

no two of which are the same?

[Jay] How do you construct
a 26-mile underground railroad

through the center
of a bustling city?

[Chris Dulake] With all of these
excavations underground,

it's a dangerous place to be.

[Jay] And how do you create a
man-made wilderness

in the heart of an urban jungle?

The client was obsessed.
"Make it as green as possible."

[Jay] This is the
age of the extraordinary.

[Amma Agbedor]
It's totally different

from anything around it.

It's like a visitor
from another planet.

[Jay] Where ingenious engineers

have unleashed
unchecked creativity.

Now their secrets are revealed

as we discover the amazing
stories of their construction.

[Mat Picardal] You look
at this building,

and your brain
just screams at you,

"This building
does not make sense!"

[Jay] To try and understand...

...how did they build that?

My favorite fact
about skyscrapers

is that in strong winds,

they can sway by up to two feet
in any direction.

Now, architects allow
for this wherever they work,

but especially when
the 82-story,

876-foot skyscraper
they're building is in Chicago,

otherwise known
as the Windy City.

So, when you see
this next building,

all those wonderful shapes
and sculpted ledges,

they aren't there just
to look pretty.

[Jay] Chicago, Illinois, is the
birthplace of the skyscraper.

And having built
them for 140 years,

they've gotten pretty good at
putting up your standard tower.

Thin, fat, short, tall,
there's a lot of them here,

but most are hardly pushing
at the boundaries.

[Jay] That is, until the start
of the 21st century.

When the developer
of a new high-rise

picked an unexpected architect
for the job.

It was kind of a surprise,
because I had never really

designed a tall building before.

[Jay] Her design for over
700 apartments and condos

with outdoor space
challenged how skyscrapers look,

how they work,
and how they're lived in.

This is Aqua Tower.

So, how did they build it?

It's 2006.

In downtown Chicago, near
the shores of Lake Michigan,

a huge regeneration project
is underway.

An area near the former docks,

once crisscrossed by railway
tracks, is being transformed.

The next new building to go up
will be a mixed-use skyscraper.

And it's going to be a big one.

The entitlements
for the overall master plan

permitted a few
of the building sites

to be extra large, extra tall.

Aqua was one of those.

[Jay] At over 800 feet,
it will join an exclusive club

of the 20 tallest buildings
in Chicago.

And the developer
wanted to make an impact.

[Sean] It needed
to stand out architecturally,

but it has to be
financially viable.

And for a developer,

that often means kind of
boring, rectangular buildings.

[Jay] To avoid that trap,

they turn to a local
up-and-coming architect

whose work
has been winning awards.

Her style
is almost like an artist.

It's very sculptural.

[Jay] The choice comes
with a huge risk.

[Amma] When you're building
hundreds of feet into the sky,

you want a safe pair of hands,

meaning you want to
work with a team

that's maybe done a project
of this scale before.

[Jay] That most definitely
isn't the case

with Jeanne Gang.

This was my first tall building.

I really didn't imagine
that I would be

even doing a tall building
at that point,

because most of my work
was smaller scale

and with communities.

[Jay] That experience of working
with communities, though,

inspires Gang to make
this skyscraper different.

There wasn't much outside space
for tall buildings,

especially in Chicago.

And there wasn't a way
to easily meet your neighbors.

They were all kind
of a bit isolating.

So it was really ripe
for reinvention.

[Jay] Her design does just that.

It turned a blank, boring,
rectangular building

into, really, a sculpture.

[Jay] What she comes up
with is a blueprint

for an undulating building
covered in rippling balconies.

Built in a
densely developed area,

each is designed
to maximize the views

and be perfectly placed
for the residents to interact.

But making them a reality will
be a huge engineering challenge.

First, they'll need to
find a way to anchor

the 800-foot tall tower

in the notoriously
unstable Chicago ground.

Then they'll have to
design curved balconies

for the 82 floors, no two alike,

before building them
to the demanding schedule

of a commercial development.

Finally, they must find a way
to stop the wind

that typically whips around
tall buildings

from making these precious
outdoor spaces unusable.

In 2007, work starts
on the foundations.

With the final tower
measuring 876 feet tall,

they've got to be substantial.

The first step is to drill

massive steel and concrete
foundation columns

100 feet down into the bedrock.

Usually, this would be
fairly straightforward.

But here, there's a big problem.

Underneath this site is
an abandoned railroad network.

The ground is riddled
with disused tunnels.

It's like trying to drill piles
into Swiss cheese.

If the foundations aren't
rooted in solid ground,

it puts the whole building
at risk.

[Jay] The team has no choice.

They're going to have to
block off every tunnel

and then find a way to fill them

to make sure they don't collapse
under the weight of the tower.

They decide the solution is
something called flowable grout.

Flowable grout is
an engineer's dream.

It'll fill
the hole you need filled,

minimal shrinkage,
it dries fast,

and you can pump
it for long distances.

[Jay] They may know how to fix
the problem,

but it's no easy job.

It's so dangerous working in
those old, disused tunnels.

I mean, you have no idea what
condition they're in.

Having a safe system to get
the people down there,

putting in bulkheads
to seal off the tunnels,

and eventually flooding
them with the flowable grout.

So a lot of coordination
and a lot of effort.

[Jay] It takes almost 5,500
cubic feet of grout

to fill the tunnels and
three days for it to solidify.

Only then can the foundations be
built and then capped off

with a 12-foot-thick
steel reinforced concrete slab.

Next, the team turns
its attention to the tower.

The key to its success
is going to be the balconies.

As well as
providing outdoor space

and a sense of connection
to the neighbors,

Jeanne Gang hopes they will also
give the residents good views.

Something unexpected
in the boxed-in site.

The idea that I had was just
to make it

almost like a topography that
would allow you to, like,

kind of peek around the corner

where you normally wouldn't
be able to see.

[Nehemiah Mabry] It's an
incredibly simple

and clever idea
to gain better views.

You essentially stretch
the building out here and there.

[Jay] To work out the views
from each balcony,

the team painstakingly uses
a scale model of the area

and lots of string
to show the sight lines.

Then they deploy
computer modeling

to design each
of the curving balconies,

which extend out
between two to 12 feet.

Now, they have to work out
how to build them.

To make the curved balconies
look really elegant,

they need to be free
from any visible support.

They need to look like they're
holding up their own weight.

[Jay] To do that, they turn to a
bit of engineering magic.

[Corina Kwami] The balconies are
basically cantilevers,

so sticking out bits of the
building that are made rigid,

and supported by hidden beams
within the structure.

Our structural engineer gave us
some parameters,

and so it was kind of like,

"Do it within these boundaries
and draw within the lines."

We could cantilever
more on the corners,

and less in certain areas.

[Jay] With the design down,

the next challenge is
building the 82 floors

to the relentless demands of a
commercial budget and schedule.

[Sean] For super tall buildings,

the faster you build
the building,

the faster you can get to market
and generate revenue.

So, a lot of the focus
happens on

how long it actually takes
to do an individual floor.

[Jay] The quickest and
most efficient way

to pour floors
is to have a repeatable design.

But to create Jeanne Gang's
undulating balconies,

that won't work, because each
is designed around the view.

You're looking at creating
a unique and bespoke floor plate

for each and every floor.

How the heck do you build
80-some floor plates,

no two of which are the same?

[Jay] In Chicago,

the team building a new
867-foot-tall skyscraper

is wrestling with the challenge
of building 82 floor plates,

no two the same.

It risks blowing a hole
in the schedule and the budget.

So, the team comes up

with an ingenious,
but experimental, system.

They create a giant tray.

Made in sections,
it's big enough to hold

the entire floor plate
of each story,

including the balconies.

Inside it, they carefully map
out the curving balcony areas,

creating a special mold
in steel.

[Randy Bullard] We started
working with different gauges,

or thicknesses,
of metal forming system

that would allow us
to bend and curve

the form systems
for each particular layout.

[Jay] The tray is then ready
to fill with concrete.

[Dave Eckman] When
the concrete had cured,

they were able to pull the
flexible slab edge away,

which then just became
a straight piece of steel again.

And then once that
floor is done,

that steel can be moved

to do the same thing again
with a different shape.

[Jay] It's not just the
steel edging that gets reused.

With this system,
the entire mold is, too.

[Eamonn] When the concrete had
reached a sufficient strength,

the whole assembly would
roll out like a kitchen drawer

and then be picked up by
a tower crane,

and then flown up to
the next level and repeated.

[Jay] With this
kitchen drawer technique,

the building flies up.

[Sean] They got to a
three-day pour cycle

for a floor plate
that was somewhere between

14,000 and 15,000 square feet.

[Jay] As the tower rises,

the team has to take on
its last big challenge:

the wind.

There's a reason why
high-rise buildings

don't normally have balconies.

It can be incredibly windy
up there.

[Jay] Not only can the wind

make the balconies
uncomfortable to sit on,

it could make the entire
building sway dramatically.

[Sean] High-rise buildings move.

It's a natural thing
that they move.

They are designed to move.

You just don't want them
moving too much.

[Jay] In a lot
of tall buildings,

engineers put huge tanks of
water or oil in the top floors,

which counteract
the effect of the wind.

The problem is these take up
so much space in the building

that could be used
for the apartments.

[Jay] But at Aqua Tower,

the balconies are
so cleverly designed,

there's no need
for a counterweight at the top.

[Corina] By chopping up the
surface of the building,

the balconies break up the wind,

dramatically reducing
the impact on the tower.

[Jeanne] We've tested a model
in the wind tunnel tests,

and yes, indeed, it actually
does disrupt this wind flow

and helps with ameliorating
the pressure on the building,

but also making it more
comfortable.

[Jay] In 2009,

two years after breaking ground
and three years sooner

than would be typical
for a building this size,

Aqua Tower welcomes
its first residents.

[Priscilla Mims]
It is just exquisite.

There's really no other building
in the city

that looks anything like it.

[Jay] It's a high-rise
that offers its residents

an indoor-outdoor living
experience like no other.

[John Fitterer] We live
on the 68th floor.

I can go outside.
I can get fresh air.

We have a summer party
out there.

And it is very much like
a community living at Aqua.

[Priscilla] It's a
neighborhood within itself.

And it's amazing
that just creating

that in-and-out pattern
of the balconies

can do that to a
tall building like this.

[Jay] In the birthplace
of the skyscraper,

Aqua Tower has truly
earned its place.

Aqua has really made its mark
on the Chicago skyline.

Even if you don't live there,

you come upon it, and it's
something special to discover.

[music]

For busy cities the world over,

good, fast, reliable
public transportation is vital.

Over in London, a huge project
to build a new subway line

beneath the streets
of England's capital

was recently completed
to great acclaim.

Although, the first train
did arrive a little late.

A full 80 years, in fact,

after the project
was first proposed.

But, boy, was it worth the wait.

[Jay] Welcome to the
Elizabeth Line.

A 73-mile-long railroad

complete with 10 brand-new
state-of-the-art stations.

To build it, the team
had to dig 26 miles worth

of underground tunnels.

The scale of the engineering
is breathtaking.

[Jay] The challenges and risks

were like nothing
encountered before.

We're tunneling under the most
expensive property in Europe.

[Jay] At stake was
a city-wide subway

designed to last 120 years.

[Howard Smith]
The Elizabeth Line is

a once-in-a-generation railway,

a legacy that will just grow and
grow over the decades to come.

[Jay] The result
provides passengers

with a smooth, spacious,
and very speedy journey

across the capital
of the United Kingdom.

The Elizabeth Line
is one of the 21st century's

greatest
infrastructure projects.

[Jay] So how did they build it?

[Jay] Britain is the birthplace
of the railroad.

But the way the system
evolved in its early days

left the capital, London,
with an enduring problem.

In the 1840s, so many people
wanted to build railways

in London, that
there were plans to cover

almost the whole of
Central London in railways.

So a royal commission said,

"Let's keep railways
to the edge of the city."

[Jay] With all the trains ending
at the outskirts of the city,

passengers were forced to take

alternative transportation
into the center.

Even when the subway arrived
a few decades later,

it didn't resolve the issue.

Everybody was getting off big
trains, going down escalators,

and getting onto small trains

to go around the center
of the city.

[Jay] In the 1940s, when
the city was looking to rebuild

after World War II,

a plan was devised
for a new cross-London railroad.

It would take passengers
through the heart of the city

on underground tracks
without changing trains.

But with so many other
infrastructure projects

needed in the aftermath of
the war, it took a back seat.

Fast forward six decades,

and a new version of the idea
is on the table.

[Howard] From 2004 onwards,

we got to planning what's become
the Elizabeth Line.

So, it's an old idea
of taking big trains

and allowing people
to travel straight through,

from outside
into the middle of town,

and one that's become a reality
for London in the last 20 years.

[Jay] The daring plan
is to carve out

a 73-mile continuous route

that will start
40 miles west of the city,

passing through
Heathrow Airport,

through the city center,

and then to the UK's financial
center at Canary Wharf,

before terminating
20 miles further east.

The main challenge will involve
sinking a 26-mile network

of supersized tunnels
deep beneath the city.

Eight giant tunneling machines

will have to excavate
interconnecting routes,

starting from the west
and the east of London,

before meeting in the middle.

The team will also
have to design

ten giant new stations

that will serve both the
new and existing subway lines,

Integrating the Elizabeth Line

with the existing
transportation network.

In May 2009, work starts on
the first of ten new stations.

Canary Wharf in East London,

where a huge $650 million US
underground station

must be built in time
for the eastern tunnel

to pass through it,

before meeting the western
tunnel in Central London.

[David Johnson] The real
challenge for Canary Wharf

was if there were any problems
with the construction works,

we would then delay
all of the tunneling works,

and that would have a knock

on to the whole completion
of the project.

[Jay] The challenge
for engineers

is that Canary Wharf
sits on the River Thames,

and the proposed station will be

in one of London's historic
docks, 90 feet underwater.

[David] All of the works
were within the water

of the West India docks.

This gave us a lot
of challenges in terms of

how we could dewater the docks
to construct the station.

[Jay] To create a dry
construction site

in the middle of a dock
calls for

a clever piece of engineering
known as a cofferdam.

Similar to the lock on a canal,

it works by damming water
on one side

so the other side
can be drained dry.

It's tricky enough to achieve
on any site,

but here the challenge
is even greater.

[David] The traditional
cofferdam construction

would use sheet piles,

which would either be vibrated
or driven into the ground.

This would obviously
create lots of noise

and lots of vibration
from the works.

[Jay] But Canary Wharf is home
to the UK's financial district,

and the headquarters

of some of the world's
largest banks, and insurers.

We had 100,000 people
working around the site,

and also hotels and residents
in close proximity,

and we couldn't spend
three or four months hammering

or vibrating sheet piles
into the ground.

[Jay]
They need to find a way

to build
the cofferdam silently.

[David] We actually had
two machines

specifically made
for the project

that were shipped over
from Japan,

where they'd already
developed a system

for pressing in
large diameter tubes

into similar ground conditions.

[Jay] It's the first time
this type of engineering

has been used in the UK.

Instead of hammering,

the Japanese method silently
presses and pulls

the sheet piles into place,
using hydraulics.

One by one,
the interlocking sheet piles,

each 61 feet high
and 4 feet wide,

are pressed into the dock bed.

[David] We targeted to install
three piles per day,

and we did
that over three months,

and completed 310 piles,

installed within
about a four month period.

[Jay] The last step is
to pump the cofferdam dry.

Over three weeks, we pumped out
60 Olympic-sized swimming pools

in terms of volume of water
from the cofferdam

to create our dry working site.

[Jay] Now, the giant
new underground station

can begin to take shape.

[Howard]
A great big concrete box

constructed 260 meters long.

You could tip some of the
really big buildings in London,

put them on their side,
and they'd fit quite neatly

into something like
Canary Wharf Station.

[Jay] With the
station work progressing,

the team can move on
to their next challenge,

and it's a big one.

[Jay] To create the
26-mile underground section

of the route,
they need to start digging.

[Corina] The machines you need
for a job like this

are not available at Home Depot.

And there are only a handful
of companies that actually

manufacture the equipment
that is required to do this job.

[Jay] The equipment in question
is a tunnel boring machine,

or TBM, worth
$15 million US apiece.

The team orders
eight from Germany,

but they're too big
to ship whole,

so they're delivered in pieces
and rebuilt on site.

It's no easy task.

[Corina] Building a TBM
is like building a bridge,

or a major piece
of infrastructure.

You have to build foundations
where you're making the TBM.

It's that heavy.

[Jay] Finally, in May 2012,
tunneling begins.

[Chris Dulake]
It was phenomenal.

It was an exciting time
for anybody involved.

[Jay] They operate like
huge mechanical worms,

chewing at the face
of the tunnel,

and pulling earth onto an
internal screw conveyor.

That earth is then expelled
from the rear of the machine.

Designed to work 24-7,

they can bore 330 feet
of tunnel per week,

operated by a crew of 12 inside.

If everything goes to plan.

But that's a big if when you're
tunneling under the center

of one
of Europe's biggest cities.

The industry
has a bad track record

in collapses in urban centers.

[Mat Picardal] The greatest
risk you face when

you're digging underground
is support.

How do you make sure
the earth around you holds up

when you're burrowing down?

[Jay] If the tunnels
collapse underground,

then the buildings above
could sink.

The team needs
to tread extremely carefully.

[Chris] With all of these
excavations underground,

as soon as you lose control,
it's a dangerous place to be.

[music]

[Jay] In London, engineers
building a new rail line

with ten new stations
and 26 miles of track

running deep beneath the city

need to make sure their enormous
tunnel boring machines

won't destabilize buildings
above as they dig.

Part of the solution comes from

the machine's
ingenious in-built technology.

[Chris] As they drive forward,

you're able build a precast
concrete lining

behind the machine
from a series of rams

that sit around the
outside of the machine

that enable you to
lock that lining in

and then drive forward.

[Jay] Shoring up the tunnel
as they go isn't enough.

The drivers also
need to maintain

steady and constant pressure
at the machine's cutting edge.

If we didn't control
that amount of movement

and that face pressure,

we could induce quite a bit
of ground movement

that would have affected
the buildings above us.

[Jay] The slightest
movement underground

can have huge
consequences above.

[Jay] As the
Western Tunnel reaches

London's theater
and shopping district,

engineers monitor the impact
of micro-movements

on some of Europe's
most expensive real estate.

[Chris] And there were
some significant buildings

that we were tunneling under.

So for every single structure
that fell within

the one-millimeter contour of
movement at surface,

we predicted the level of damage

to the building
that would occur,

and if it was
an unacceptable level of damage,

we applied a process
called compensation grouting.

[Jay] It works by injecting
high-pressure grout

underneath the building,
which expands, lifting it up.

[Chris] It sounds like
a complex process,

but as the buildings
above settle,

as you tunnel underneath,
you compensate for that movement

by pushing them back up.

We installed about 60 kilometers

of pipework to deal
with those movements.

And yeah, they worked very well.

[Jay] While the network
of tunnels takes shape,

teams are hard at work
across London

completing the ten new stations.

It means even more digging,

and creates one heck
of a pile of dirt.

[Chris] All of those underground
constructions in London

totaled about 6 million
cubic meters of material.

And so the biggest challenge was
getting that out of London

without impacting on the public.

[Jay] Removing it by truck
will add

half a million road journeys

to an already congested capital.

For moving that sort
of stuff any distance,

you want to put it on rail
or you want to put it on water.

[Jay] The answer runs through
the heart of London,

the River Thames.

[Howard] Night and day,
conveyors running,

bringing spoil out into barges
and taken down the Thames.

[Jay] Even better, all that
earth doesn't go to waste.

25 miles along the estuary,
it's used to create

an entirely new wetland
and bird sanctuary.

We had over 4 million meters
cubed of material placed there.

And that enabled us to then
break the seawalls down,

so that we allowed the tide to
come back in over those areas,

then reinstated a wetland.

[Jay] In 2022,
the Elizabeth Line opens.

With over 130 million journeys
made on it each year,

it has expanded London's
rail capacity by 10%.

[Julian Robinson]
To leave a great piece

of infrastructure
for London, fantastic.

What do you ask for in a career?

[Jay] In the ten new stations,

smooth, sculpted
concrete tunnels

encourage people
to flow through them,

While clever lighting maximizes
the sense of space.

Every detail has been
thought through,

right down to how they sound.

[Neil McClements] We
incorporated thousands

of acoustic perforations into
the crown of the tunnels.

And this creates a really soft
acoustic environment

for passengers, a calm,
almost Zen-like atmosphere

away from the hustle and bustle
of the city above.

[Jay] The line is predicted
to add $55 billion

to the British economy.

And it's connected dozens

of previously
underserved communities.

People are able to look
for new houses or for new jobs

that they couldn't have got
to before.

You know, that's a boost
to the city itself.

The Elizabeth Line?

Game changer.
Absolute game changer.

[music]

Azabudai Hills
might not sound like

a bustling
neighborhood development

in the center of
the Japanese capital of Tokyo,

but this earthquake-proof wonder
is way more green

than its urban location
might suggest.

Not only does this
city within a city

have a living roof from which
thousands of plants

grow down to ground level,

it also processes sewage,
and then uses it

to control the indoor climate.
Genius.

At 37 million people,

Tokyo has the highest population
of any city in the world.

And they all need somewhere
to live and work.

Tokyo has one of the lowest
areas of natural greenery

per person for a large city
in the world.

[Jay] But in the late 1980s,

a developer set out
to change that

with a groundbreaking piece
of urban planning.

Creating a complex of
homes, offices,

a hotel, shops, and restaurant,

including the tallest skyscraper
Japan has ever seen.

[speaking Japanese]

[Jay] And surrounded by
six acres of green space

in the heart of the city.

The client was obsessed,
"Make it as green as possible."

[Jay] Realizing this vision
took almost 35 years.

It meant negotiating
with over 300 landowners.

The team had to ensure it would
survive in one of the most

earthquake-prone cities
in the world.

Building in a zone like this is,
everything has to be bigger.

Everything is
much more tightly braced.

[Jay] All in a bid to change
the face of Tokyo forever.

This is Azabudai Hills.

So, how did they build it?

Half of Tokyo was destroyed
by Allied bombing

in the Second World War.

In the postwar years, the
city saw a huge redevelopment,

but money was concentrated
on buildings, not green spaces.

Toward the end
of the millennium,

people were realizing how
detrimental this could be.

[Corina] Studies have shown
that green areas in cities

not only mitigate climate change
and improve air quality,

but also bring
communities together

and contribute
to the local economy.

[Jay] In the late 1980s,
developers Mori Building

decided to transform a 20-acre
area of downtown Tokyo.

Their vision is to create
a green oasis

where people can
live, work, and play.

[speaking Japanese]

[Jay] To do this,
they will first need to get

more than 300 individual
property owners

to agree to their land
being redeveloped.

Then, the plan is to put

most of the living, working, and
retail space into three towers,

one of which will be
Japan's tallest building,

leaving room to create
six acres of green space

across the complex.

We're building seven
or eight million square feet,

but it's all vertical.

It preserves the land for
human use, for green space.

It's a much, much better way
to build a city.

[Jay] The team knows
this will be a model

for other cities to follow.

So, it will need
a revolutionary design.

To start,
they will need to demolish

the existing buildings
on the site.

Then, create
separate foundations

for the three towers,

individually suited
to their different needs.

After that, they will need to
figure out how to

make sure the tallest building
in Japan will stand strong

in the most earthquake-prone
city in the world.

Finally, they'll have to fit in
shops, bars, and restaurants

at ground level, while also
creating the lush green spaces

that the client wants.

The piece of land chosen
for the project

is in the densely populated
Minato area of Tokyo.

The first challenge
is persuading

more than
300 individual landowners

to agree to the redevelopment.

It's like taking on a project

the scale of the
Rockefeller Center in Manhattan,

and getting 300 individuals to
cooperate in making it happen.

[Jay] No easy task.

But in exchange,
they are offered units

in the completed development.

[speaking Japanese]

[Jay] Not surprisingly,
it's a slow process.

In Japanese culture, building
consensus is really important.

They even have a special word
for it called nemawashi.

And things take
as long as they need to.

[Jay] No one could have
predicted, though,

that it would take
more than three decades.

[music]

[Jay] In Tokyo, Japan,

it's taken over 30 years to win
over more than 300 landowners

and navigate the complex
Japanese planning system.

But finally, in 2019,

work begins on a bold new
mixed-use development,

incorporating not one,
but three skyscrapers

surrounded by acres of greenery.

Building this anywhere
would be a challenge.

But here,
it's especially difficult.

Tokyo is a hugely active
earthquake zone.

So, authorities prefer
to keep buildings

shorter and wider to make
them earthquake resistant.

Here though,
architects Nihon Seiki

and U.S. firm
Pelli Clark & Partners

must work together
to design three huge towers,

including the tallest
Japan has ever seen.

Earthquake-proofing them
starts from the foundations.

All of the towers are sitting on

what is called
a matte foundation.

It's a very stable,
huge slab of concrete, frankly,

embedded in the earth.

It is critical in the sense
that it spreads

the weight of the building
over this big concrete platform.

It doesn't concentrate
the weight in any singular are.

[Jay] The tallest tower
will be 1,000 feet.

Building its 16-foot-thick
matte foundations

takes 15 months.

By 2020, after a total
of 274,000 cubic yards

of concrete have been poured,

the groundworks for the
entire complex are complete.

The next challenge
is to design and build

the steel structure
for the towers.

These also must be super strong.

[Michael Lewis] The main thing
is structure is big.

The columns are much bigger
than we're used to.

The beams are much bigger
than we're used to.

And, of course,
you have to brace a lot more.

[Jay] In an earthquake zone,
strength needs to be balanced

with flexibility
so that the building can move

and absorb the impact

without collapsing
under the strain.

And because the effects
of an earthquake on a skyscraper

are magnified the taller it is,

the team has to use
every shake-resisting trick

in the book.

The towers will be fitted
with giant oil dampers,

or shock absorbers,

more than 300
in the tallest tower alone.

But the seismic measures
don't stop there.

[speaking Japanese]

[Jay] They design
1,200 metal braces

in the walls.

Made from soft steel,
they effectively absorb energy

during large quakes.

And they'll add huge weights
at the top of each tower.

These will move
in the opposite direction

to the building
during an earthquake

to counteract
the swaying motion.

For most buildings, they only
usually have one or two

of these technologies, but this
building has all of them.

[Jay] With the tower safe,

the team moves on
to making them green,

including installing a very
unusual heat recovery system.

[speaking Japanese]

[Jay] Using the sewage to heat
the building in the winter

will reduce the tower's
CO2 emissions

by about 70 tons a year.

As the towers near completion,

the team faces
a fresh challenge.

Realizing the vision
for a natural green wilderness

in the heart of the city.

Although the skyscrapers

have freed up space
at ground level,

this premium city real estate

is also needed for
shops and restaurants.

Figuring out how to squeeze in
enough greenery

falls to Heatherwick Studio.

The green area requirements
for this area

in Tokyo are quite ambitious.

It was clear that we wouldn't
just be able to have

conventional buildings
next to a garden,

that we would need
to integrate the two.

[Jay] Luckily, Heatherwick's
previous projects include

1,000 Trees in Shanghai
and Little Island in New York.

So they know about imaginative
ways to green a city.

We almost started
with a diagram of

"What if it's just
a green valley?

And in fact, our site sat
within a natural valley?"

And we started to think, "Well,

"could we just exaggerate
the valley in some way?

Could we start
to lift up this landscape?"

[Jay] They devise a world first.

A giant pergola will stretch
like a net over the shops below

and be covered in plants.

The big question is
how to build it.

The construction
of the pergola system has been

probably the biggest challenge
on this project for us.

The geometry itself
is obviously curved.

It's curved in elevations,
but it's also curved in profile.

Which means that you don't
just have a single curve,

you have what we call
a double curve.

[Jay] To create
the undulating double curves,

Heatherwick works with
the architects and engineers

to design a custom frame
built from bent pieces of steel.

Before a more natural-looking
finish, they want to

cover it in panels of
glass fiber reinforced concrete.

This is a very
lightweight concrete,

which means you can get
very thin panels

and use a lot less concrete.

It also is reinforced
with glass fiber,

not steel, which makes
it lighter and easier to make.

[Jay] These specialist panels
will be prefabricated offsite.

and craned into position.

The problem is they need
so much of this special material

that Japan runs out.

Production switches to China,
which means shipping them over.

[Michael] Shipping panels
from one country to another,

it's not just as easy
as finding a ship to do it.

You have to look
at controlling the temperature

of the concrete panels,

controlling the moisture content
of the shipment vessel,

because any change in the
moisture content, or too much

of a change in temperature
could compromise the panel.

[Jay] After a nervous wait,

in 2020,
the panels arrive unscathed.

Now comes the task of
assembling the intricate,

curving, three-dimensional
jigsaw puzzle.

Our biggest fear was
the coordination of those

concrete panels with the
other components on the facades.

[Jay] If this complex puzzle
doesn't go as planned,

the pergola is
at risk of collapse.

[Michael] So you have concrete
meeting aluminum curtain walls

or concrete meeting the floor
where it meets stone paving.

[Jay] To make matters worse,

it's the middle
of the COVID-19 pandemic,

and the architects
are stuck in London,

unable to supervise in person.

We've had some long calls.
Six or seven hour calls.

It was very stressful,
that time.

[Jay] Over the coming months,

the team follows
things remotely,

and watches as everything
falls into place.

All that's left is to fill the
pergolas with the 320 varieties

of plants and trees
that will breathe new life

into this corner of Tokyo.

In November 2023,

after nearly
35 years of waiting,

Azabudai Hills finally
welcomes back residents.

And it's a triumph
on a huge scale.

It's really unusual to feel such
a natural and wild environment

in the center of a city,

and I think that's been
the biggest surprise for me.

[Jay] Over 90% of
the previous occupants

have opted
to return here to live.

[speaking Japanese]

[Jay] They've done
the seemingly impossible,

creating a lush green space
in the middle of Tokyo,

and building
the tallest tower in Japan

capable of withstanding
the most violent earthquake.

There's individual elements
that I love and little moments

where I like to kind
of go and spot and walk through.

I guess the one thing
I'm really proud is

how it all stitches together.

[Jay] They have created
a model for urban living

that could inspire a generation.

For me, Azabudai Hills
is the pinnacle of my career.

[music]

♪ MTV ♪