All language subtitles for How.Did.They.Build.That.S04E03.Speedcore.and.Steambend.1080p.FUBO.WEB-DL.DDP5.1.H.264-FFG_track3_[eng]

it reinvigorates
a forgotten neighborhood?

We had to build
this ceiling structure

with two crews at once,
and then there was this moment

where they had
to meet in the middle.

We weren’t sure
was it gonna actually meet.

How do you build
a 1,500-foot bridge

that supports itself
almost entirely from above?

There were
many sleepless nights.

This tensegrity bridge,
it had never been attempted

anywhere in the world.

And how do you build
a colossal skyscraper

in record time with
an engineering technique

never used like this before?

Everyone came with
this mentality,

we don’t know how
we’re gonna get it done,

but we’ll figure it out.

Welcome to a world
where anything is possible.

The space where innovation
and creativity collide.

This isn’t just impressive,
it’s revolutionary.

Where the only limit
is human imagination.

This wasn’t just
ambitious, it was audacious.

No one had ever attempted
anything like it.

Unpacking the miracles
and mysteries of construction.

Sometimes buildings
can change the world.

And this is one of them.

To ask...

How Did They Build That?

You know that phrase

"So many books,
so little time"?

Well, when an inspiring
new library was proposed

for Calgary, Canada,

it was more a case of
"So many books

"and a totally unsuitable site
for a building

big enough to keep them all in."

Of course, if there’s one thing
great architects love,

it’s an "impossible" project.

And the building they produced

is seriously worth
shouting about--

even inside a library.

Shh!

Oh, sorry.
Shh, shh. Sorry. Sorry.

At the turn
of the 21st century,

Calgary, Alberta
is one of Canada’s

fastest-growing cities

thanks to its thriving energy
and financial sectors.

But Calgary’s
East Village neighborhood

has been struggling
to keep up since the 1940s.

It hadn’t really
been taken care of.

There was a lot of buildings
that were in disrepair.

Things only got worse
in the 1980s

with the introduction of
the new light rail train.

When the light rail
transit line went in,

it was literally
a physical barrier.

It cut off access between

the west of the city
and the East Village.

The city decides it needs

to reinvigorate
this part of town.

And in 2007, plans are
drawn up to redevelop it.

Our challenge was to change
perceptions of the district.

At the heart of it
will be a brand new library

built on a plot of land

with the train tracks
running right through it.

The new Central Library project
became an opportunity

to reconnect these
two parts of the city.

They settle on a design
from a local company, Dialog,

and global firm, Snohetta,
a company with a reputation

for complicated buildings.

So the difficult site
doesn’t daunt them.

In fact, it inspires them.

We realized that the library
could be formed

around the curve of
the train line

so that the library
could lift itself up

over the train line

and then create this prow,
like a boat,

towards the center of the city

and connect the east side
and the west side of the town

where it had previously
been cut off.

I think that at the start,

we knew that we were on to
something

that had
the potential to be great.

The architects’ goal
is for the building to be

much more than a simple library.

Sitting on top of the tracks,

it will bridge
the two parts of the city.

First, they will have to
find a way

to safely enclose
the 600-volt electric cable

that powers the trains

and figure out how
to keep the noise from

disturbing the readers.

Next, they need to find a way
to support the elevated building

and the 180 tons of books
that will be inside.

To join the two sides
of the tracks,

there will be a passageway
under the library.

Its complex curving design
will mean

bending thousands
of pieces of wood,

each to the
exact right shape.

But they will need to do
all of this

without disrupting
the train service

running through the site.

If they can pull it off,

they will have
successfully reunited

Calgary’s downtown
with the East Village.

So this is a project

that actually was gonna
be a challenge

from day one

all the way, actually,
to the end of the project.

The team arrives
on site in spring 2014.

Their first problem,
working out how to build over

one of the busiest
rail lines in North America,

which carries 90 million
passengers a year.

When we started looking at
the plans and visiting the site,

the reality set in as to
how close

the active railway corridor was
to the geometry of the building.

It will require
both a feat of engineering

and steady nerves

as the team works
to carefully enclose

the active train tracks

in a concrete box
almost 500 feet long.

We’re doing all this work,

which is very complicated
anyway.

And in the middle of it all,
you have a train passing

and the passengers
are waving at you.

And it’s like,
what is happening?

Now they need to install
the roof.

It was directly
over top, you know,

just a few inches above

the contact wire
that has thousands of volts.

If you even get close,

there’s a chance of
getting electrified.

You don’t even have to touch it.

Turning the power off
costs US $100,000 a day.

So the transit company will
only allow one 48-hour shutdown.

The only way they stood
a chance of getting the roof in

quickly enough
was to make it off-site.

Huge concrete panels
were prefabricated,

then lifted into place
like a giant puzzle.

At midnight
on August 22nd, 2015,

the power is turned off.

And then the 24 hours,
it was go, go, go.

All these pieces
had to fit perfectly

and had to be
erected seamlessly.

All 60 of them,
and each one being unique.

It’s a race
against the clock.

There was a lot of anxiety.

A lot of anxiety with that.

Finally,
with eight hours to spare,

the last panel
slides into place.

Once that roof was placed,
there was a huge moment,

sigh of relief.

With the light rail
enclosed,

in September 2015,

the team can start work
on the library itself.

But finding a structural system
to hold it up

is a massive challenge.

Engineers love columns.

Plenty of vertical supports

that direct forces down
into the foundations.

The trouble here was

the architects wanted
a grand, open entrance

without
a single column in sight.

The books alone will weigh
an incredible 180 tons.

How do we take all
of these enormous loads

and transfer them
all the way down the building?

So the solution for that

was to design very large
structural steel trusses.

The huge trusses were built

from interlocking triangles,

which are nature’s
strongest shape.

They don’t just hold the weight,
they distribute it perfectly,

making them nearly unbreakable.

80 enormous steel beams,

the largest 170 feet long
and weighing 30 tons--

the same as a humpback whale--

are welded together

to form the five
enormous trusses.

There’s weeks of welding.

Weeks and weeks of welding.

Then, as the trusses
are being put together,

they discover a massive problem.

There was a couple members
where the steel,

after the fabrication,
had a series of hairline cracks.

Even the tiniest fault
in those massive steel trusses

could cause the whole
building to collapse.

They had to be rock solid.

No one really knew
what was causing those cracks.

The team realizes the issue is

in how the steel is being made.

Steel isn’t perfect.

Every single piece
has tiny flaws.

If it cools too fast,

these flaws
turn into stress points.

And stress points
turn into cracks.

Those can lead to big trouble.

To overcome it,
they start again,

this time with
a slower cooling process.

It solved the challenge.
We didn’t see it happen again.

And by November 2016,

the fifth and final truss
is in place.

The team can move on
to the next challenge,

making sure the noise caused

by vibrations from
the passing trains

doesn’t disrupt the library.

Instead of the concrete being

rigidly connected to
the pile foundation,

you basically
break that connection.

And it’s a series of layers
of rubber pads and steel

that help dissipate
that rumble from the tracks.

Over the next six months,

they build the main structure

before wrapping it in almost
500 crystalline panels

to create the glimmering facade.

Finally, the building’s beauty
is starting to shine through.

When you’re inside,

walking along the corridors
alongside that facade,

which is getting
all of these reflections,

it’s like being
in a kaleidoscope.

The next major challenge
will be

creating the wood-covered passageway,

which was inspired by
the weather

over the Rocky Mountains.

When two pressure systems meet,
they create this arched cloud,

this vast arch,

and it can stretch 100 miles
across the horizon.

It’s called a Chinook cloud.

To create this swooping
overhead entrance,

they decide to use
locally sourced

Western red cedar timber--

beautiful, durable,
and sustainable,

but not very pliable.

Once you bend a piece of
wood to a certain point,

I mean, eventually it cracks,
it splits, it breaks.

In Calgary, Alberta,
Canada,

the team behind
an incredible library

built on top of the
city’s light rail train

are creating a swooping entrance

made from local
red cedar timber.

But how do you bend
a huge wooden arch

without breaking it?

You reboot technology
used by the ancient Egyptians.

Steam bending works by placing
wood into a sealed box

and filling it with steam.

The heat and the moisture
soften the wood just enough

to bend it into shape--

but only for
a short, critical window.

It created this incredible,

intense moments in manufacturing

where it would be, okay, go,
guys, the steam box is ready.

We’re taking
the battens out of the box.

We gotta
run over to the jigs,

push them down
before they kind of harden.

Twisting and bending
the arch in two directions

is incredibly complicated

and needs some
21st century technology

to help pull it off.

We created a highly accurate
three-dimensional computer model

of the entire ceiling structure
to be able to know exactly where

each piece of timber should go.

And we used incredibly
complex software algorithms

to actually model the geometry
of each individual wood batten.

Then, the 21,000 square feet

of curving cedar
needs to be fitted quickly.

Due to the schedule,
we had to build

this ceiling structure
with two crews at once.

So we started from the ground,
as you can imagine,

with one crew,
and we started way over here

at the other end
from the other crew.

And then there was this moment

where they had to
meet in the middle.

We weren’t sure,
was it gonna actually meet?

Four months after starting,

they’re about to find out.

I still remember
our site supervisor calling me

and he was like, it fit!

Just an incredible
moment, right?

After four and a half
years of construction,

on November 1st, 2018,

Calgary’s incredible
new Central Library

opens its doors to the public.

That opening day
was so amazing.

To see everyone else see

what I’d seen over
the last five years

was very emotional.

When we first came here,

we were like,
wow, this is amazing.

Definitely we have to come back.

I walked in here
and it was like,

wow, I couldn’t believe
what I was seeing.

It didn’t look like
a library to me.

This is breathtaking.

But this is more
than a library.

Its extraordinary timber-framed
walkway sits above the railway,

healing the divide
between the East Village

and the rest of downtown.

With the addition
of the library,

East Village has really gone
from a part of our downtown

to being a part of Calgary
that shouldn’t be missed.

A temple to reading
unlike any other on the planet.

It’s just such
an incredible building

and an incredible library.

I think Calgary
has absolutely redefined

what a library can be,
and I would argue should be.

When architects were tasked to
build a new skyscraper

on a super tight deadline,

they turned to
a never before used

construction concept to
get it done--

SpeedCore.

And while any new
engineering technique

comes with a degree of risk,

the people of Seattle
were less concerned about

the building going up

as they were about
the 50-year-old

architectural masterpiece
next door crashing down.

Seattle is the largest
metropolis

in the Pacific Northwest,

with a stunning skyline
to prove it.

And in 2014,
there are plans for

a colossal new skyscraper
to join it.

The build site is on
a block that is already home

to the beloved Rainier Tower,

a skyscraper whose chewed bottom
has earned it a nickname.

Locals call it
the Beaver Building,

and it was designed by
Seattle-born architect

Minoru Yamasaki,

who’s best known for
New York’s Twin Towers.

So it’s pretty special.

Not surprisingly,
the space comes with

some seriously tight
building restrictions.

Any development plan for

the remaining
three quarters of the block

should not obstruct the views

in the
original Rainier Tower.

That, though, isn’t enough

to stop Seattle architects NBBJ

from coming up with
a radical plan for

58 stories of mixed-use space

Retail at the bottom,
offices in the middle,

and then 18 floors of
residential units at the top.

Building it will come with
a whole set of challenges.

Because first, they will have
to dig down 100 feet

to create the foundation
without bringing down

its 50-year-old
neighbor in the process.

Then they must stop the soil
around the foundation

from caving in.

A traditional concrete core
is gonna be too slow

and too expensive.

So they need to find
a revolutionary new way

of holding the building up.

And when they’ve done all that,
the finished tower

needs to complement
the Beaver Building

and not get in the way
of its views.

Definitely probably one of
the more complicate projects

that I have been part of
and our team has been part of.

On May 8th, 2014,
the team wins the contract.

The search for
an engineer is on.

Luckily,
they don’t have to look far.

The building was literally
right outside of

my personal office window,
60 feet away.

Having worked in the
Beaver Building since the 90s,

Ron knows the site,
warts and all.

Of the many challenges on
this building,

one that we faced
straight away, was

how are we going to make
the below-grade levels--

the basements, if you will.

The new Rainier Square tower

will have a six-story
parking garage, all underground.

And that means
digging a very big hole.

But still very daunting where
you’re going to dig

a 100-foot hole
immediately adjacent to

an occupied 40-story building.

So this was kind of
challenge number one.

In Seattle, work starts
excavating for the foundation

of an enormous 58-story tower,

which will sit feet away

from one of the city’s
most iconic buildings.

It’s nothing if not challenging.

How do you do that
while not putting in peril

the existing 40-story building?

Its extraordinary shape

makes it
all the more difficult.

What’s really unique about
this particular tower

is that the base of
the tower is a pedestal.

This incredibly small footprint

means it’s putting even more
pressure

on the soil beneath.

To stop the excavations
from bringing it down,

the team must hold the soil
under the original tower

in place by
building a huge wall.

The best analogy
I can offer you,

if you can imagine a dam

that’s holding back not water,
but dirt.

And that dirt happens to have

a 40-story
building on top of it.

Perhaps, not surprisingly,

this wall
needs to be pretty special.

The actual dam,
or the wall, that we built

is a secant pile wall.

A secant pile wall is a set of
overlapping concrete columns.

Normally, a secant pile wall

might be 24 to 30-inch
diameter holes.

In this case, we had holes
that were 5 feet diameters.

With the wall in place,
work progresses very carefully.

There was a very extensive
monitoring system set up

to determine if the
building itself

was moving in any way
that was of any concern.

It moved, but it moved
within expectations.

It all performed as it
was intended to perform.

Their next challenge

is going to be
building the tower.

Around the world,
many, many tall buildings

have been designed and
constructed using what is

a reinforced concrete core.

It’s a column that runs through

the center of the tower

and usually houses
the elevators and stairwells.

It’s what gives big
skyscrapers their strength.

It’s a tried
and tested method,

but here, there’s
a pretty big problem.

We made an evaluation of
the cost and the time required

to build that design.

And the conclusion was that

it cost too much
and it took too long.

And that was our cue

to introduce
this idea of SpeedCore.

Developed in the 1990s
in the United Kingdom,

the SpeedCore building
system was largely unknown.

At the time,
I’d never heard of it.

But it had been used in
nuclear facilities before

for blast resistance,
but never in a high rise.

The concept of SpeedCore is

to prefabricate steel modules

and then stacked up
one on top of another,

kind of like Lego blocks.

Then to add to its
strength and stiffness,

fill them full of concrete.

Using it here to create
the tower’s strength

will be revolutionary.

What’s amazing about the
SpeedCore is you’re able

to build the core
and the floors at the same time,

which is where you’re saving
a huge amount of time.

In theory,
building this way

will make it
cheaper and quicker.

We’re able to go back
to our client and report,

lo and behold, we think we can
save 10 months on the schedule.

And the client says,
go for it.

So 170 miles away in Portland,

they start fabricating
the steel module.

These panels are very large.

They were 14 feet tall
and 30 to 40 feet long.

And they weighed on the order
of about 9 tons each.

In October 2018,
the first steel panels arrive

on site in Seattle.

As an engineer,
this is a huge moment.

If it works, it will reduce
the schedule by months.

If it doesn’t,
it will be a disaster.

The team hold their breath
as work gets underway.

The first job is putting
the steel modules in place.

The core is composed of a
bunch of sandwich panels.

And then they’re joined together

to the next panel to
complete a core section.

Our panels were welded together.

We didn’t want to do
a bolted connection

because having
to line up bolt holes

is very, very difficult.

In the end, there was 26 miles
of welding in this building.

Normally, you do not
measure welding in miles.

That’s not a unit of measure
that’s very typical.

As they’re filled with
concrete, the tower shoots up.

The biggest difference
is just seeing the units

put together at such a speed

that you’ve never
really seen before.

They were able to set one
entire floor of walls in a day,

in one day,
as opposed to five days.

But as they get to
850 feet,

there’s a very different
challenge--

the team needs to defy
the laws of physics.

Pumping concrete at height

is really kind of technically
challenging.

Just pumping something up
850 feet,

you need to overcome
the force of gravity

to overcome the friction
within the pipe.

To pull this off,

clearly any old concrete
isn’t going to do the job.

We knew that it needed to be
high strength.

It needed to be very flowable

because it was
going to have to flow

from one module into the next.

So we worked on
an appropriate mix.

What they came up
with was a thinner mix

with no aggregate in it
that would fill the modules.

The only downside was that
it would take longer to set.

It’s a huge success.

The SpeedCore knocks months
off the construction schedule,

leaving the team ready
to face their next challenge--

the glass facade.

This is by far the most complex
project that I’ve ever done,

and I think that we
as a company have ever done.

In Seattle,
work is about to begin

on the curving glass facade

that will maximize
the tower’s floor space

while keeping
the neighbors’ view.

But building it
will be a nightmare.

The geometry of
each floor is different,

so it just creates a lot of
unique challenges for us.

There are steps up to level 40,

and each floor has a unique
step inward to the building.

Usually,
a skyscraper’s glass skin

hangs on an aluminum frame,

where the bars that hold
the glass in place

slot together neatly,
floor after floor.

But that doesn’t happen here.

Because every floor
steps back a little,

the vertical bars don’t line up.

Instead of nice,
clean, 90-degree angles

like you’d normally have,

every connection
is off by a little bit.

To overcome this,
they turn to a technology

used in aeronautics,

but rarely in construction.

What we ended up deciding to do

was look at a way to have a node

that was 3D printed
out of aluminum

that kind of takes up
all the geometric complexities

and into this printed part.

It turned out really good.
It’s super precise.

With each set
of connectors

individually printed,

the team can now seal
the building

with the thousands of windows
that make up the exterior.

It’s cool because
no matter what side

of the building you look at

and what corner
you’re looking at,

there’s so many
unique aspects of it.

In September 2020,

the last window
slides into place,

finishing the three-year build

and revealing
Rainier Square Tower

in all its glory.

It’s the most iconic
project that I’ve ever done,

and I think we’ve ever
done as a company, too.

It’s up there,
highlight of my career.

At 850 feet,
the 58-story tower becomes

the tallest mixed-use building
on Seattle’s skyline,

elegantly complementing
the iconic tower next door.

Seattle has been
changing significantly

over the years,

and to be able to add
a significant project,

to me, this is

a once-in-a-lifetime
opportunity.

With 734,000 square feet
of office space

and 189 luxury apartments above,

it may dwarf the neighbors.

Its clever design, though,
gives Ron

the best seat in the house
to watch over it.

Every day that
I came into my office,

I was able to see the progress,

I was able to see the speed
at which things were happening,

and even somewhat frighteningly,
seeing the steelworkers walking

on the steel beams
in outer space,

30 or 40 stories in the air,
right outside my window.

It actually gave me
knots in my stomach.

Creating this tower

has truly been
an incredible journey,

with results
that speak for themselves.

Everyone came with
this mentality of,

we don’t necessarily know how
we’re gonna get it done today,

but we’re smart,
and we’ll figure it out.

Would you use this toy
to build a bridge?

In Brisbane,
Australia, they did.

Well, sort of.

Architects use the same
principles of tension

and compression that
makes this toy enjoyable

to create one of
the most revolutionary

and fun bridges on Earth.

How did they do that?

In the early 2000s,
the city is growing fast.

It needs a new bridge to
cross the Brisbane River,

linking the Northside’s
busy city center

to the Arts District
on the South Bank.

It was thought
that it would be good

to have more connections
across that river.

A pedestrian and cycle bridge
out of the city,

so that more people would walk
and be healthy and cycle.

So the city launches
a competition for a bridge

that will complement Brisbane’s
buzzing Arts District.

The bridge is located virtually

at the front door of
the Gallery of Modern Art.

It needed to be a piece of art,
a big piece of art.

The engineers behind
the iconic Sydney Opera House

think they’ve got
the winning idea.

We looked at lots of
different bridge types,

but the one that met
the brief best in terms of

being unusual and wonderful
was this idea of

a lot of masts and cables

to make it look
like a sculpture.

So how do you build a bridge

that’s also a work of art?

You attempt something
that’s never been done before.

Use a little-known engineering
principle called tensegrity.

Tensegrity exists in sculptures,
like this,

where tension cables, like
these,

hold isolated elements,
like these rods, in place,

creating a stable,
self-supporting structure.

Local architects
Cox Rayner

are up for the challenge.

What excited us all was trying
to do something

that hadn’t been done before.

The thing about tensegrity
is it doesn’t make sense.

And that’s
the mystery of tensegrity.

You end up with something
that looks like it’s made

out of sticks and string,

or cat’s cradle, as my son
called it when he first saw it.

The idea is that the
entire bridge

will be supported from above

by this cat’s cradle system
of poles and wires,

instead of by
pillars underneath.

If they can pull it off,
it’ll be a world’s first.

This was an opportunity to see,

can we apply the principles
of tensegrity to a real solid,

big structure
and make it effective?

The team hopes
to build a bridge across

a 1,000-foot-wide bend
in the Brisbane River

using tensegrity.

And that will be
both highly functional

and look like
a piece of art.

First, they will need to find
somewhere

to construct
the two supporting piers.

One in the river itself,
clear of the shipping lane.

The other on
the crowded North Bank,

home to an eight-lane
freeway and bicycle path.

Next, they’ll have to find
a way to support the bridge

while they
build out from each pier.

And they need to make sure
both sides meet in the middle.

Then, somehow,
the entire bridge

needs to be supported
from above

with a complex system of
cables and wires.

And, as if that’s not enough,

the whole thing has to be
finished in time

for the state of Queensland’s
150th birthday party

in two years.

This tensegrity bridge,
it had never been attempted

anywhere in the world.

And we saw this as
a milestone for Queensland.

The place chosen
for the bridge

has great significance to
the people who lived here first.

Before work can start,

the team consults
with the local tribes.

For thousands of years,

it was the main crossing
area for the tribes.

Parents would carry their
babies on their shoulders

or even the mothers

on their babies
because it wasn’t very deep.

There’s great cultural
significance with

the particular bridge location.

We were a little bit nervous

that we might not be doing
something

that the traditional owners
thought appropriate.

They spoke to us

and asked us
if we wanted to be involved.

And we gave
the name for the bridge.

Kurilpa refers to
the little kangaroo rat

that’s on the bend
of the Brisbane River.

That’s the meaning.

Kuril is
the little kangaroo rat,

and pa , place of.

With the bridge named Kurilpa,

work begins in December 2007.

The first job is finding
somewhere to sink the two piers

that will anchor the bridge
on each side of the river.

There were
many challenges to the site.

One was we had to cross
a freeway on the city side,

which was operational.

There’s a navigational
channel as well,

which usually in this river
is somewhat in the middle.

But in this particular location,

it was located over
towards the South bank side.

A site is found
in the river

that sits clear
of the shipping lane.

But it brings
many more challenges.

We had professional divers
that had to go down

and dig the shelf and start
the very first temporary pier

in muddy water that had
basically zero vision

with great knots of
water going through.

It’s critical that these piers

are gonna be strong enough

to withstand whatever
nature throws at them.

The Brisbane River is well
known to be prone to flooding.

So you try and make sure that A,
you can resist the floodwaters,

but B, anything floating down
the river on the floodwaters.

In Brisbane, Australia,

the team is
in the middle of constructing

an extraordinary
new pedestrian bridge,

which has to be tough enough
to handle a collision.

The largest barge,
I believe, is like

a 2,000-ton barge
going out of a control,

coming down
in a flood event.

So they had to
withstand ship impact.

And that means anchoring
it to the riverbed.

The main river pier of
the Kurilpa Bridge is supported

on approximately 16 piles
that go 18 feet into the rock.

They’re socketed in.

But the only way we were able
to socket those in

is to basically drive through
the alluvium

that was at
the base of the riverbed.

Approximately 10 feet
filled up with grout,

a bit of concrete for
mass or damping effect.

They’re all joined together,

and we concreted
the pole cap in there.

With the in-river pier
secured

on the South Bank side,

the challenge is finding
somewhere to build a pier

on the North Bank.

You had the Riverside
Expressway,

which is
the busiest motorway,

basically, in eastern Australia,
or definitely in Brisbane.

You had the
Bicentennial Bikeway.

And you had the Brisbane River
itself.

The only space to squeeze it

is between the eight-lane
expressway

and the city’s main bike path.

We had to carefully bring a pier
up between the two structures

and also maintain the operation
of the Riverside Expressway.

To keep the project on track

and traffic disruption
to a minimum,

the team works
through the night.

You can imagine
all the lead-up work

to understand
what the total numbers were

and understanding
the peaks in traffic flow

in the Riverside Expressway

and actually how many
night closures we’ll need,

how many day lane
closures we had to make.

Very challenging.

After 12 months,

with both bridge piers in place,

attention turns to
the next challenge.

How to build the 420-foot
deck between them.

The problems of
tensegrity

are to do with construction,

because it really only
works when it’s finished.

All the cables are stretched,
and they’re all taut,

and they all work in concert.

But when you’re building it,
the cables are slack,

so nothing is supporting
the bridge deck.

Where all the cables
and poles are tight,

the system works together
to create

this perfect balance of tension.

But when they’re not tight,
the whole thing stops working.

There’s no support at all.

The team has to find a way

of supporting the bridge
while they build it.

We wanted to avoid putting

any temporary piles or piers
into the river itself

that would get in
the way of navigation.

So it was a very intimate
collaboration

between
builder and engineer,

unusually intimate,
to exactly work out

the construction methodology.

Their answer is to build
the bridge out one mast and unit

of precast deck at a time

and hope it stays up.

There were many
sleepless nights.

It was always a fear
that something could drop

from that bridge
under construction.

That was my main concern.

It was this idea of

a self-extending
construction method.

You held up one bit of bridge

from a mast
you’d already erected,

then you put down another mast,

and that held up
the next bit of bridge.

As they build out,

temporary support struts
hold up the bridge.

To make clear
which are permanent massed,

the temporary supports
are colored red.

We had a lot of
temporary works there,

and that’s when the structure
is challenged its most,

when it’s under
those extreme forces

and under
temporary works control.

You know, you’re going
over one piece at a time,

you’re connecting
one cable at a time,

and to make it all
match up to the millimeter,

that was pretty challenging.

As both sides
of the deck extend out,

the question is,
will they meet in the middle?

As you build it,
it moves a lot

’cause the cables stretch.

At some stages, it was up
to a meter out of position.

So there was a nervousness.

You knew it had to be swaying

because there was nothing
holding it there.

So as
the last piece comes along,

you still don’t know,

because it’s still
a long way out of position,

whether the piece will do
the job it’s meant to do

and lower it just enough
to make it join together.

But the bridge
went in absolutely perfectly...

...which we thought was
an astounding achievement

by the combined team.

It means the cat’s cradle
of cables and masts

can be locked tight

to start
holding up the bridge,

and temporary support
struts can be removed.

It was a great moment.

Gave everybody a great sigh
of relief and excitement.

But with less than
four months until opening,

there’s a problem with the deck.

So since
the Tacoma Narrows Bridge

in America,
which failed in the 50s,

we’ve known that some bridges,

if they have
very thin bridge decks,

are susceptible to galloping

or lateral torsional
twisting in the wind,

where the bridge ends up
collapsing because it twists

more and more and
more as the wind goes.

Kurilpa Bridge was found
to have that susceptibility

when we modeled it
in a wind tunnel.

Which isn’t good news in
a city like Brisbane

that’s vulnerable
to tropical cyclones.

So the team comes up with an
elegant engineering solution.

So we added little fairings
on each side that just control

the wind enough
to stop that effect.

The simple triangular
fairings

improve its aerodynamics

so the wind flows over
the walkway

and doesn’t catch it,
making it twist.

It prevents it from starting,

and therefore you never get into
that mode of instability.

Finally,
on October 4th, 2009,

Kurilpa Bridge opens
to the public.

And in time for the state’s
150th birthday.

I came up to Brisbane
for the opening.

Everybody was overjoyed because
it came out exactly as we hoped

it would at the beginning.

We just felt that
we’d really created something

that contributed to the city.

I like it
’cause it’s an olive branch

that we were asked
to be involved.

There was a time
that wouldn’t even be

a second thought, to talk to

the traditional
people from the area.

And at night,

a photovoltaic lighting system
transforms it

into a colorful work of art.

The bridge is beautiful.

It allows people to stop on
the way to sit above the river.

There’s little seats there.

It’s a wonderful sight.

I go for my runs
every single day on it.

I use it for
daily walking as well.

I use it every day I’m at work

so that I can go for
a walk at lunchtime.

And then back up that hill,
that’s a great workout.

I love it.

It’s just nothing
like I’ve ever seen before.

I never really thought
as project director

that it would put Brisbane
on the map.

I couldn’t be more proud of
this project.

A true world first.

Kurilpa Bridge takes its place

as one of the most audacious
and technically ambitious

ever built.

♪ MTV ♪