Original subtitles

[Narrator] Why did engineers build an upside down skyscraper?

[Hayley] If you suffer from vertigo,

this building is not the one for you.

[Narrator] How can a restaurant sit 18 feet below

the surface of the North Sea?

[Corina] An underwater restaurant is wild enough,

but putting it on one of the planet's stormiest coastlines

is off the charts.

[Narrator] And how do you engineer a heavy metal library?

[Jay] that was the equivalent of 20 Statue of Libertys.

[Narrator] This is the age of the extraordinary.

[Hayley] It's like one of those insect-eating plants,

only enormous and white.

[Narrator] Where ingenious engineers have unleashed

unchecked creativity.

Now their secrets are revealed.

As we discover the inside stories of their construction.

[Corina] This is an incredible feat

of planning and engineering.

[Narrator] To try and understand

"How Did They Build That?"

All right, we start the program with a tower like no other,

built in an earthquake zone that looks like a twister.

Now, this building is a real marvel.

By which I mean it's a real building

that looks like something out of a Marvel movie.

Yet the incredible Vancouver apartment block

that you're about to see is not a superhero fantasy.

There's no big muscles. There's no CGI.

They really made this!

[Narrator] Vancouver, British Columbia.

Canada's most densely populated place.

Here every square inch counts.

But right in the middle of the city is a plot.

A small triangle of land,

hemmed in on all sides

and subject to stringent planning laws.

[Michael] There's a force field that the city of Vancouver just

said "thou shalt not" and there's no negotiating that.

[Narrator] No one's worked out how to build on it,

until radical architects come up with a gravity-defying design

for an architectural marvel.

[Hayley] If you suffer from vertigo,

this building is not the one for you.

[Narrator] A tower that gets wider as it gets taller,

appearing as though it could topple over at any time.

[Corina] We all know that for ultimate stability,

you need a big base that gets smaller as you go up,

not the other way around.

[Michael] The bigger concern was

what's going to happen in an earthquake?

[Narrator] It's 59 storeys of skyscraper

that forced engineers to flip tower construction on its head.

This is Vancouver House.

So how did they build it?

In 2014 with property prices shooting through the roof,

developers are eyeing up every square inch of real estate

in Vancouver.

Because of this, a site previously considered

too small and tricky was on the table.

Right in the center of the city it should be prime real estate,

but its proximity to Granville Bridge

brings with it a serious planning headache.

The city has banned building homes near busy, main roads,

which is certainly the case here.

The city of Vancouver has safety offsets from bridges

and it's similar to all their bridges.

It's about 98 feet you can't encroach within.

It is 98 feet not just sort of horizontally,

but it's sort of an envelope that you can't have structures

encroaching it.

Imagine a 98-foot bubble around the bridge,

and nothing else is allowed to sit within that bubble.

[Narrator] And as if that isn't enough,

any development there can't cast a shadow over the local park

making the area even smaller.

Coming up with a design that overcomes the restrictions

and creates a building big enough to make a profit

will require architects to do some serious

thinking outside the box.

But then that's what Danish firm, Big are known for.

Take Copenhill, a power plant topped with a ski slope.

The circular eight house housing project,

the Marsk watchtower.

For them, there really is no such thing as a problem.

This is a good example of how constraints work

in the creative process.

What we always try to do is define the parameters

that the project should fulfill,

and use them as drivers in the design process.

[Narrator] So out of the tiny, triangular plot

their plan is to build a stunning new skyscraper,

which will bend its way around the bridge

and get wider as it gets taller.

Pulling this off and stopping it from tipping over,

will need some serious engineering.

The columns holding up the larger upper floors

will have to navigate the building's massive curve

and merge, getting thicker as they go down.

Thousands of feet of tensioned steel rebar will run all the way

from the top of the building to the bottom,

literally pulling it into place.

And to make up for the small footprint,

the foundations will be super deep.

It's an ingenious way to get the most out of a

limited plot like this.

[Narrator] Of course, it's all well and good

having innovative design ideas,

but someone has to make sure that when they build it,

it's going to stay standing.

[Michael] The architect came up with that form

and then it landed on our desk and said how can this work?

Turn it upside down. And it works great.

[Narrator] And put very simply, having a larger building

at the bottom getting smaller at the top

would have overcome most of the engineering problems.

[Ellie] A building with a square or rectangular floor plan,

the gravitational pressures are fairly equal.

Every floor is pushing down with a fairly equal force.

But with this building, every floor is a different shape.

This means that by the time you get to the bottom

of the building, the forces at the back of the building

are different from the sides

and different again from the front.

And the result is a building

that not only wants to fall over,

but it wants to twist as it does it.

So, it's up to the engineers to accommodate

and neutralize all those forces.

The obvious concern is the building wants to fall over

under its own weight.

But for us locally,

the bigger concern was what's gonna happen in an earthquake?

[Narrator] To find out, the team builds a computer model

of the tower and tests it to see what happens if it's hit

by an earthquake similar to some of the worst

in North American history.

Like the magnitude seven, Vancouver Island quake of 1946,

which caused chaos across 100,000 square miles,

triggering devastating landslides

and fires.

[Michael] Our initial runs show that we could come up

with a design that was within those limits.

Then test it against twice the maximum credible

earthquake expected.

And with some tweaking of the design,

we found even at that level

we could keep it within allowable drift limits.

So we've essentially designed it for double what any other

building in Vancouver would be designed for.

[Narrator] It all looks well and good on paper

and computer screens,

but just how well will that translate to a

real-world skyscraper?

In 2016, it's time to find out.

Work gets underway,

starting with the supersized, super strong foundations

critical to the building's success.

The basement under the tower was quite deep.

It was a challenge to get that far down

with such a small footprint.

[Narrator] To anchor a building into this tiny plot,

the team intends to create

140,000 cubic feet of foundations.

It will weigh a staggering 10 and a half thousand tons.

And it's essential that if it's to be strong enough,

all this concrete is poured in one go.

If you have a break when pouring concrete foundations like these,

you can have what they call a cold join,

which is essentially a crack.

This is where the bottom layer has set

and the next layer doesn't bond properly to it.

And with a building like this,

you don't want to take any chances.

[Narrator] What that means is all the concrete

needs to be poured before any of it sets.

It's going to be a major challenge.

[Michael] It was the largest continuous concrete pour

in Vancouver's history.

[Narrator] Next,

can they pull it off?

[Narrator] In Vancouver, Canada, work is underway to create

the foundations for an extraordinary new skyscraper.

All the concrete needs to be poured in one go

before any of it sets

or it may not be strong enough to do its job.

This needs some serious organization.

It was the largest continuous concrete pour

in Vancouver's history, up around 4,000 meters.

It was so large that no one company could do it.

So all three of the major concrete suppliers in Vancouver

were involved.

And once it started, they couldn't stop.

So it was basically 24 hours of concrete trucks rolling up,

the concrete getting placed, moving on, the next one in line.

[Narrator] The pour takes 24 hours straight,

But thanks to the team's meticulous organization,

It's done.

With the foundations complete,

the engineers now turn their attention

to building the columns

which will hold the building up.

[Michael] Because the building grows as it as it comes up,

one of the challenges, well, how are we going

to support each of these floors as they get bigger?

[Narrator] On three sides, there isn't a problem.

The columns go straight up and down

like in a regular skyscraper.

But on the fourth, the building twists

and gets bigger, creating a massive challenge.

How to transfer the force created by the bigger floors

above down through the building?

If they can't find a solution,

the top floors will be left unsupported

and at risk of collapse.

[Michael] On one side of the building,

by the time we're at the base,

the building's only seven feet wide.

So a seven-foot-wide column to hold up 53 stories

is quite a challenge.

[Narrator] Because the floors are smaller at the bottom,

so are the spaces where engineers

can put the structural supports.

But somehow, they've got to support everything above.

[Michael] What we came up with was at the top of the building

where the floor plate's large, there's a series of columns

and they come down.

As the building starts to come in the column steps down

and joins the next column in from the edge,

and join the next column down.

All the columns are of course, coming down here vertically.

But then they start to walk in here,

so that basically one column ends up carrying the load

of four columns at the top.

[Narrator] On their own,

these columns may not be enough to hold the building up.

We all know that for ultimate stability,

you need a big base that gets smaller as you go up,

not the other way around.

[Narrator] The clever design has overcome

the site's planning issues,

but created some very real engineering challenges

in the process.

To help give the building enough strength to deal with the bigger

floors at the top, the engineers construct a very special spine.

First, they run steel rebars linking it top to bottom.

The bars are anchored into the large footing at the base

to give the weight to pull against

and then they were run up continuously,

so every floor they're coupled with high-strength couplers.

[Narrator] They plan to tension the steel rebar every so often

using a hydraulic tensioner.

Turning it on for the first time

should start to pull the spine straight.

For the building, it's a momentous moment.

For everyone else, not so much.

[Michael] We were all very excited when we head

to the first point of putting tension into the bars

to see what would happen.

And I guess, in your head,

that you're expecting this grandiose thing.

It's literally just this hydraulic cylinder

that goes over top of the bar.

And they stick a compressor up to it,

doesn't take very long.

And the little gauge says the force in it.

You put a bunch of nuts on it to lock it off.

And that was kind of it. It was very undramatic.

[Narrator] Finally, in 2019, Vancouver House is completed.

And the results blows the city away.

[Thomas] Obviously, as an architect all buildings

are controversial and some people like the work

we do and some people don't, but I think in this case

we've had very positive feedback.

[Man] If you are going to build skyscrapers,

I would like to see more unique buildings like this.

[Woman] We're lucky to have such a unique building in our city.

I love it. Absolutely, I love it.

[Michael] Just seeing it and seeing the attention it got.

And being able to say like, you know, we participated in that,

I think is yeah, it's very exciting.

[Narrator] This twisting, turning tower is not just

a thing of beauty, it's a gravity-defying wonder,

showing that overcoming limitations can lead to

some of the most creative thinking

and daring engineering imaginable.

When I visit a seafood restaurant,

the experience for me is always way more enjoyable

if the restaurant is by the sea.

Delicious food as close as it's possible to get

where it was caught.

The only way to be any closer would be to eat in a restaurant

that's actually in the sea itself, say 18 feet below

the icy waves of the Norwegian North Sea.

But they couldn't, right? They could.

And they have.

[Narrator] From majestic fjords

to the magic of the northern lights,

Norway has some amazingly special experiences to enjoy.

But in 2014, a hotel owner decided it needed a new one.

A fine dining restaurant that would be like no other.

A place with an eye-popping view of a completely different world.

An underwater restaurant is wild enough, but putting it on one

of the planet's stormiest coastlines is off the charts.

[Narrator] Creating a restaurant 18 feet below the surface

of the North Sea would test engineers to their limits.

I think it was the most stressed I've ever been.

[Narrator] It would take four years

and over eight million dollars to build one of the coolest

restaurants on the bottom of one of the world's coldest seas.

This is the Under Norway Restaurant.

So how did they build it?

[Narrator] It's 2014, and in Norway,

hotelier, Stig Ubostad has a rather mad idea,

to combine two of his favorite activities,

fine dining and scuba diving,

when he decides to build an underwater restaurant.

To do a thing like this,

you need to have a passion for the sea.

And I've been diving since I was a small kid.

It's fantastic.

[Narrator] Stig's family-run hotel

sits on the southern tip of Norway's coast,

exposed to the full force of the North Sea.

Building it on land wouldn't be exactly easy,

so imagine trying to build it under the sea.

This spot in Norway is where the storms

from the north and the south collide.

[Stig] We can get waves up here to four or five meters

at the highest.

[Narrator] Below the waves, strong, nutrient-rich currents

attract a diverse range of marine life.

We wanted to have in rough seas, not in sheltered water

because the marine biology is a lot different.

[Narrator] Stig's plan is to create a restaurant

where diners can enjoy swimming with the fishes

while sampling the very best the sea has to offer.

What's more,

they won't even have to dip a toe.

To help pull this off,

he brings in the team behind the Oslo Opera House.

The architects at Snohetta know a thing or two about

building beauty by the water.

This though, will be something different again.

It was a kind of a crazy idea, to build the first

and biggest underwater restaurant in Europe.

That was actually the brief.

[Narrator] Although a few underwater restaurants exist

in places like the Maldives,

none has to withstand the day in, day out force

of the North Sea.

Not only will it need to be beautiful,

but also, very, very tough.

We couldn't create a building where you,

at any point would feel unsafe, going underwater, for instance.

So all these things came together with a

very stiff kind of concept.

And we created more like a pike that intersects with the water.

[Narrator] The architect's ingenious design

calls for a tube of concrete 111 feet long

with walls about two feet thick.

One end will be attached to the shoreline,

while the rest is submerged under the sea

to create a huge, sunken periscope.

It's piece de resistance will be the world's largest clear,

acrylic panel, 36 feet wide, 11 feet high

and 12 inches thick.

This will create a widescreen window

into the watery world beyond.

To avoid being swept away by the powerful waves,

the restaurant will be firmly anchored to a concrete base

connected to 18 steel piles sunk into the seabed deep below.

If there's one thing an underwater building needs,

it's firm foundations.

[Narrator] Luckily, building heavy-duty structures

is big business around here.

The oil rigs and pipelines needed

to exploit Norway's oil fields,

mean local engineers are experts in building structures

that can survive this seriously hostile environment.

Well, we get a phone call one day saying,

oh, I've got this underwater restaurant that needs to be

installed onto the seabed. Can you guys help?

I hear that you're local and

know how to do marine engineering.

[Narrator] Normally a structure like this

would be built on dry land, moved on heavy haulers

and finally lifted into the sea.

But the cost would be enormous.

So instead, they decide to build the whole thing

on a barge on the water.

It's a cheaper solution

but comes with its own set of problems.

[Ben] Every time you have to pour a concrete formwork,

you end up changing the stability of the barge.

We had to tell the guys, well, if you pour 100 ton

of concrete over here, then you need do something

with the ballast water in the barge over here.

Otherwise, it might all end up upside down.

[Stig] And also, one of the biggest challenges is

if you get that in addition with the high seas and big waves,

it's always moving around. So it was quite challenging.

[Narrator] These aren't the only waves

the team has to worry about.

They need to make sure the structure is going to be

strong enough to cope with whatever hits it,

even if that's a once-in-a-decade storm.

To do that, Ben turns to a piece of

cutting-edge computer technology.

So the wave analysis is a really interesting point.

It's based on computational fluid dynamics.

Computational fluid dynamics are calculations

that mimic wave actions.

[Ellie] In this case, they can create a hypothetical,

powerful storm 12 miles offshore

and calculate the exact size and power of the waves that,

that will create at the restaurant site.

[Corina] They can then feed these loads into the

structural analysis for the design

and then strengthen it accordingly.

[Narrator] They take advantage of Norway's endless summer days

to move the build forward.

Work pushes on creating thick concrete walls,

ceiling and floors.

And to minimize the chance of fractures and leaks,

the main outer structure is built as one completely,

continuous concrete shell.

Wooden molds are used to create the shape around a network

of reinforcing steel bar.

At one end,

there's an opening for the huge underwater window

36 feet wide and over 12 feet high,

which is being made at a specialist factory

in the Netherlands.

[Rune] The special thing with this, is it also,

this is 25 centimeters thick

and it's made out of acrylic, 11 meters wide

and I think 3.8 high and it consists of

three different pieces, which are glued together

so that's very special with this big window

that also its position in the construction,

so the water pressure itself

make it even more watertight because of the pressure.

[Narrator] The completed shell weighs 2,500 tons.

It's now got to be moved to its final position

across the bay

before being sunk and fixed to its foundations.

First, they need to get it off the barge and into the water,

which normally wouldn't be too much of a challenge.

[Ben] When we install big oil rigs offshore,

we use barges that are properly sized.

So we sink the barge down

and you can float off the structure that holds

the oil platform on top,

and everything goes extremely smoothly.

But in this case,

the barge that we built the restaurant on was too small.

[Narrator] Conscious of project costs,

the team builds the concrete structure on a small barge,

but that creates a new problem to overcome.

So if we tried to submerge that barge

with the restaurant on top of it,

there was a 100% chance that it would flip upside down.

So we didn't want that, of course.

We end up having to put what we call the reaction barge

onto the end of the installation barge just like this

with a pivot point.

And it added extra buoyancy or extra stability.

[Narrator] At 3:00 AM on the morning of July 27, 2018,

the moment comes to float the concrete shell off the barge

and move it into position.

They've waited for the best possible weather,

but they can't take any chances.

So installation must be completed in one seamless,

24-hour operation.

[Stig] When doing it, it needed it to be dead calm on the sea,

and luckily enough, it was.

And we just had that one shot.

[Narrator] Stage one goes well.

But the project now faces its biggest moment of danger.

Once it has floated free of the barge,

the shell is uninsured.

[Ben] As the restaurant was coming off the barge,

that was by far the most stressed I've ever been.

[Narrator] In Norway, work is underway to build

an extraordinary underwater restaurant.

The uninsured concrete shell is being towed out

into the deep water of the bay.

Waiting there is one of the largest floating cranes

in Norway.

Only when that is attached to the shell

will the insurance kick back in.

[Stig] For the construction on the barge,

you get normal insurance, building insurance.

And when it's attached to the ship then its marine.

But in the between, you don't have any insurance.

[Narrator] To great relief, the crane is successfully attached,

and the shell is insured again.

It guides the shell in and over the concrete foundation slab

18 feet below the surface.

Now they've got to sink the restaurant,

which turns out to be a surprisingly difficult task.

[Ben] To get it down onto the seabed,

we had to pump 500 tons of seawater

into the restaurant itself.

[Narrator] Moreover, they have to do that without damaging

the restaurant's most important feature,

the 36-foot-wide window onto the underwater world.

[Ben] We have this beautiful, really expensive window,

and we couldn't put any seawater or water in general

onto the inside of the window.

So all of the water ballast is actually contained in

in massive garbage skips.

[Narrator] It takes nine hours,

but slowly,

the restaurant sinks towards the steel piles.

It is bolted onto the foundations.

[Ben] So it was quite a simple, novel arrangement,

really beautiful actually,

from an engineering point of view.

[Narrator] The rest of the time on site

is more like a traditional restaurant installation

with plumbing, electrical, insulation

and ventilation systems all added.

Bespoke furniture is commissioned

from local furniture makers

and made from local forest wood.

The world's newest and largest underwater restaurant

is finally ready.

In March 2019, it serves its first food to 40 lucky people.

The 18-course tasting menu with wine, at $430 dollars,

is of course, delicious,

but all eyes are on that unique view

made possible by that 12-inch-thick acrylic window

that bends by up to an eighth of an inch.

[Ben] That window is very special.

In fact, on the biggest storm events,

if you put your hand on the window,

you can feel the waves crashing through.

The window actually deflects,

I think a maximum of four millimeters.

[Narrator] The vibrations soon turn

from nerve wracking to good,

as the unique seafood and view combination creates a big stir

on the international restaurant scene.

[Stig] It's been immense.

We had 2.2 billion digital views within the first half year

and around 3,000 articles in 104 different countries.

This beautiful architecture,

like we saw that on the Instagram.

It's worth a trip to you know, visit here.

[Corina] I have to see it,

so I've made the earliest possible reservation

in two year's time.

You know, if engineers had their way,

we'd just make completely symmetrical square boxes

and we'd put them on the seabed with no windows.

But that wouldn't be beautiful, would it?

Our next building is one of those baffling feats of

engineering that appears to be exempt from all laws of gravity.

At first glance, this Seattle landmark

resembles a stack of books on the verge of toppling over,

which is kind of the idea, since it's the city's new library.

Watch how Seattle rewrote the book on big, bold public spaces.

[Narrator] Seattle, Washington.

Famous for its coffee, the Space Needle and grunge.

And now to add to that list, an extraordinary library.

Ready for the 21st century.

And boldly going where no one has gone before.

[Corina] This giant stack of boxes and slopes

seems to teeter dangerously over the street.

[Narrator] In building this temple to calm and quiet,

engineers would have to prevent almost 5,000 tons of steel

from toppling over.

[Jay] That was the equivalent of 20 Statue of Libertys.

[Narrator] They need to stop it from becoming too

hot to handle in summer.

[Hayley] That curtain of glass could turn the building

into a giant greenhouse.

[Narrator] And if that wasn't enough,

prevent flooding from day one.

We had a tremendous amount of groundwater pouring in.

It was pretty dramatic.

[Narrator] But that's only the beginning

because it's a building that really wants to fall down.

[Ellie] With virtually no columns to keep it standing,

it seems an impossible feat.

[Narrator] It needs a vast, steel lattice to battle

catastrophic earthquakes.

This is Seattle Central Library.

So how did they build it?

It's the end of 1990s

and America's northern-most major city is booming.

Seattle's population is now approaching half a million.

And to be honest, it's doing pretty well.

But in this modern city, there are fixtures and fittings

that are beginning to feel a bit out of place.

Not least, its library.

Established at its current site in 1960.

[Andrew] The city of Seattle was growing quickly.

And the library needed to expand its size

and range of collections, services and programs

to meet a growing population.

[Narrator] So the city decides it's time to build a new one.

But this time,

it's going to be different like no library we've seen before.

Libraries have traditionally been thought of as kind of

musty, dark places, and really, the vision

for this library was to turn that whole idea on its head.

[Narrator] The library also wants to embrace the dawning era

of digital technology.

These are the heady days of the dot.com boom.

And Seattle has some of the biggest players

right on its doorstep.

In a place that's home to some of the most

forward-thinking tech companies, the city looks outside its walls

to find someone to design it.

[Rem] It was in a very interesting moment when

Microsoft and Amazon were all emerging

and influencing the condition of Seattle.

[Narrator] They turn to Dutch architect, Rem Koolhaas.

From his revolutionary skyscraper for China's

CCTV station in Beijing,

to Holland's so-called vertical city in Rotterdam.

He's not afraid to bust the boundaries.

[Ellie] He's right up there with Geary or Hadid.

He pushes engineers to their absolute limits.

[Narrator] Koolhaas's design doesn't disappoint,

and will redefine what engineers can build.

Set on a steeply sloping downtown site,

the new library will consist of four huge boxes

stacked one on top of the other

to create an 11-story building.

But Koolhaas wants each box to be massively offset,

jutting out precariously

with just a slim, central concrete core

shared between them.

A network of ingeniously positioned super slim columns

will add support to the boxes above,

crucial in this earthquake-prone area.

Finally, sloping walls of glass will envelope each of the boxes,

exposing all areas to vast amounts of daylight.

It all creates a uniquely open, welcoming space

for research and learning.

Koolhaas's building has space for more than a million books,

but is unrecognizable as a library.

This is a 21st century information store.

[Rem] What you see is a stack of open, closed, open, closed,

open, closed elements.

This element is shifted in the direction of Mount St. Helens.

This section is shifted to have a view of the sea.

And then in-between, there was a big livingroom

where they could develop a lot and change a lot over time.

[Narrator] When the construction team sees the transparent

glass and steel design model,

they know they have an almighty task on their hands.

There's no interstitial space, you can, you can cover

over connections or anything. Everything is exposed.

In some ways its completely unforgiving

as far as a construction team is concerned.

[Narrator] In 2001, construction begins,

and they're faced with their first major challenge.

The new library is being built on the site of the old one.

And that's on a very steep hill.

[Jay] A pretty significant portion of the building

is below grade.

So structurally, how do you hold back that much dirt?

[Narrator] The team comes up with an ingenious answer

to keep the existing basement wall of the library,

which is currently holding back the hill.

[Dale] We had to support the wall laterally

before we could demolish the building.

Because the structure of the building was holding

that wall up originally.

And that proved to be a real challenge.

[Narrator] To do this, they need to underpin the wall

with vast steel piles driven into the ground.

Then they'll have to fix tiebacks,

huge iron rods, which will be attached

to the wall, then fixed securely into the ground.

But they quickly run into a major problem

that threatens to bring down the entire wall

and hillside with it.

[Dale] We had a tremendous amount of groundwater

that was pouring in along that wall,

so we had to actively de-water under the road

in order to relieve a lot of that pressure,

which was a bit of a scramble.

It was a constant challenge to mitigate all the groundwater

that was coming through.

And also, it didn't help when we were building in December,

January, February are the wettest months here.

[Narrator] With the weather fighting against them,

the team ends up constructing a new wall in front of the old one

in a last-ditch effort to prevent it from giving way.

It was a definitely pretty dramatic.

[Jay] There was a bunch of challenges for that.

They're like, I think we just kind of

outsmarted ourselves on that one, you know?

[Narrator] With the wall steady and danger averted,

the serious work of laying the foundations begins.

The next problem facing the engineers

is how to support the various floors,

which the designers want to float above one another

without using vertical columns.

For the construction team,

it seems an impossible challenge.

[Jay] When I looked at the model,

they had these little vertical columns

that they under different parts of it.

And I said, well, what are those?

And they said, well, we need those

to make the model stand up.

And I said, well, there's probably a good chance

that if you need them to make the model stand up,

I'm gonna need something like that

to make the building stand up, too.

[Dale] Rem Koolhas wanted us to remove

as many interventions as possible.

He wanted the building to look slightly dangerous.

[Jay] And that's where it got to be really tricky.

And we spent a lot of time trying to figure out,

well, how in the world are we going to do that?

[Narrator] The answer they come up with is to tilt the

supporting posts at an angle.

These raking columns will be placed at key points

around the building and will support its vast steel frame.

[Nehemiah] The benefit of raking columns is that

you can transfer the load at an angle.

The downside, however is that they require

very careful calculations. There's not much room for error.

[Dale] That made it incredibly challenging for us to build

because we had to figure out how to get these

huge columns into place at the right sequence.

[Narrator] With the help of the latest 3D computer modeling,

the team is able to work out exactly where,

and in what order,

these columns should be placed.

But if that wasn't enough,

the team also has to make sure the building will be able

to stand up to whatever mother nature throws at it.

And here that includes earthquakes.

[Narrator] In Seattle, work building the new

central library's vast steel skeleton is progressing.

But engineers have to make sure it can deal with

one of the biggest natural problems the city faces,

earthquakes.

In 2001, the huge Nisqually quake

ripped through Seattle's buildings and infrastructure.

Next to a major fault line,

the big one is expected to hit anytime soon.

[Jay] We have very high seismicity,

large earthquakes, fairly frequent.

We get relatively high wind loads through here as well.

And again, it's a lateral load,

a horizontal load trying to move the building horizontally.

[Narrator] The team comes up with an awe-inspiring solution.

They're going to cover the entire building with a vast

steel lattice of diamond shapes.

It will look dazzling and protect it.

The shape of the panel allows for redistribution

of that lateral load.

So the number of sides that it has by being diamond shaped

allows it to share the load with more adjoining panels,

making it easier to resist.

[Sam] If there's an earthquake or if there's a high wind event,

the load is transferred into the diamond grid,

and the diamond grid is resisting that.

[Narrator] There is no room for error.

This grid has to be cut and installed

with pin-point accuracy.

The stability of the library literally depends on it.

[Dale] We were really challenged because the tolerances

on the seismic steel are almost perfect.

We had to be within one half inch plus or minus

with all of it.

[Narrator] While they're building the mesh,

the team holds it in place with sections of temporary

ironwork called false work.

These have the added purpose of helping to support

the entire steel framework.

But all of that will have to come out.

[Dale] I kept asking the ironworkers for their plan

of how they were going to remove all this false work.

And they gave me this sketch.

And it showed the ironworker apprentices

torching all the columns.

The journeymen ironworkers in the bar across the street

and the structural engineer would stand in the middle

of the building.

Because they figured if the engineer was willing

to stand in the middle of the building,

then the plan must be successful.

[Narrator] Finally, the day comes for the engineers

to put their money where their mouths are.

Time for the temporary steel to come out.

There was no going back.

We literally were torching the columns off at the bottoms.

If something started to go awry,

I don't think we really had much of a recovery plan for it.

[Narrator] The team waits anxiously.

Everyone stands well back.

Will some 5,000 tons of steel skeleton remain standing?

[Dale] There was a range of anticipated deflection

that the engineers calculated, and it barely moved

within that range. It was quite successful.

[Narrator] With the steel lattice complete,

it's time for the finishing touches.

10,000 glass panes to shroud the exterior,

almost the size of three American football fields,

letting in natural light.

Though that creates the next challenge

for the team to overcome,

the heat of the Seattle sun.

[Dale] Basically, this is a giant greenhouse,

and we didn't want to have to cool the building excessively.

[Sam] We also don't want too much sun coming in

and making people uncomfortable.

[Narrator] To overcome the problem,

the team come up with an ingenious solution,

clever glass.

Each window will be made from two panes sandwiched together

and in-between there will be a tiny air space containing

an aluminum mesh to soften the sunlight

at key times of the day.

The idea is that it creates essentially like

mini sun louvers

as you look through it.

So it's transparent as you look through

and it's blocking the sun as the sun is coming down on it.

[Narrator] Invented especially for this building,

it's believed to be the one of the world's first

microscopic sunshades.

[Corina] In summer when the sun is high and hot,

they create shade.

In winter when the sun is cool and low,

they let light in. Win, win.

[Narrator] In 2004, following six years of planning,

designing and building,

the city of Seattle has an extraordinary library

ready for a new age.

It was like nothing anybody had seen before.

[Andrew] The New York Times memorably called it

a library with fishnet stockings going to the disco.

[Narrator] The 130,000 square foot

glass curtain on the outside

together with the vast, cavernous spaces on the inside,

and topped off with a 3-story book spiral in the center,

all combined to make this library

a very special place to be.

[Sam] The great thing about the spiral that it allows us to do

is to have a continuous run of books,

so the Dewey Decimal run is uninterrupted from 000 to 999.

It's never been done before.

[Narrator] The construction team on the ground

can stand proud of their success.

It's such a brilliant building.

It's such an amazing icon for the city.

[Hayley] Creating magnetic new public spaces like this

is what will keep city centers alive in the future.