All language subtitles for Superstructures Engineering Marvels Series 1 5of6 Biggest Dome 1080p

♪ ♪

♪ ♪

narrator: Like no other,

this enormous,
state-of-the-art building

dominates the entire city
that surrounds it.

Andrew steele: The singapore
national stadium

is a truly epic structure.

Benjamin flowers:
It's simply undeniably unique.

Roma agrawal: You have
this beacon of light

coming off the top of it.

Narrator:
The multi-award-winning
sports arena

is a dazzling symbol of
singapore's national pride,

but more than that,

it's architecture on a scale
never previously achieved.

Steele: It's the largest
free-spanning dome in the world.

Narrator: How on earth
do you build a dome this big?

Agrawal: It's, you know,
a real marvel

of structural engineering.

Narrator: When it opened
in June 2014,

the spectacular ceremony marked
the end of a torturous battle

against the laws of nature.

Physics as well as the climate,

and even the land
the stadium is built on,

presented a deluge
of horrendous hurdles

that came close
to defeating designers.

Clive lewis: Obviously
it's a major project

with huge challenges
along the way

to making it and realizing it.

Narrator: The only way
to find out

how architects and engineers
won the battle

to turn the stadium
into a successful reality

is to take it apart
and reveal the innovations

hidden within it.

The futuristic
singapore national stadium

is the centerpiece of a giant
$1.3 billion sports hub.

♪ ♪

dreamed up at the start
of the millennium,

the intention was
to give the city-state

a glossy, new,
forward-looking image

with a stadium that could host

prestigious
international events.

Oon jin teik: Back in 2000,
the year 2000,

singapore was really looking
at transforming itself.

It is a red dot, little red dot

in the context of
neighboring countries

in this part of the world.

We may be small, but the dreams
and aspirations of singapore

is actually very bold, very big.

Narrator: Today the stadium
stands as a testament

to those grand aspirations.

Lewis: The national stadium is
the largest free-spanning dome

in the world,
spanning over 1,000 feet.

The range of
engineering disciplines

that we were controlling
was beyond anything

I've done before in my career.

Narrator: Designing a venue
that delivers

a great experience to tens of
thousands of people all at once

is quite different to any other
engineering challenge.

And for architects,
a stadium can be

the most creative
project of all.

Flowers: This is
incredibly hard to do,

it requires a vast investment
in technology to engineer that.

And so you have to have
the right kind

of geological conditions

and the right kind of
infrastructure systems in place

to support the building
both during its construction

and during its lifetime.

Mike king:
All of these buildings
are one-offs, you know.

You're not doing it as number
seven in a series of ten,

you know, these are each
unique buildings

with their own constraints
and their own set of reasons

for coming up with various
aspects of the designs.

Narrator: The problems
to overcome can be anything

from crowd transportation

to the sourcing
of building materials.

For the singapore
national stadium,

there is one issue
that will never go away.

(thunder)

jin teik: We are located
in a tropical zone

where it not just rain,
it pours cats and dogs, right?

Narrator: In the 1970s,
the first national stadium

was built on the same site.

But it was open-air
and completely useless

against the elements.

Right from the start,
the brief for the new stadium

insisted on
a weatherproof roof.

The architects could only
come up with one solution.

It was radical and would be
a huge and very public gamble,

because it had never
been attempted

on this scale until now.

King: There's a huge
amount of pressure,

and you're always feeling that
if it didn't work this time,

then you didn't have
an alternative.

Flowers: To build an actual
structurally sound, solid roof

over a stadium is a feat of
engineering of some distinction.

Narrator: For starters, the
area of a stadium roof is vast.

And that means weight,
lots of it.

Several stadium roofs
have collapsed.

Flowers: You have to think about
the obstacles you face

whenever you enclose
a stadium of any kind,

which is how do you
hold the roof up?

And in most
conventional stadiums

that was done with columns.

Narrator: Columns are
very effective

for supporting flat roofs.

But any column system
inside a stadium

has a fundamental disadvantage.

Maxwell hutchinson:
In a large sporting arena,

the starting point
for the designer

is the field of view
of the spectator.

They want to be able
to see what's going on.

(cheering)

flowers: You don't want a column
interfering with the view

of the fans sitting behind it
of the action on the pitch.

So how do you deal with that?

Narrator: For the new
singapore national stadium,

any design with columns
is ruled out.

But a roof is still
a requirement,

and it must be
supported somehow.

Architects delve into history
for inspiration.

♪ ♪

king: Going back to sort of
roman bridges and the like,

the arch has always been
a very natural form

for resisting
uniform gravity loads.

That's why they work well for
bridges, and even naturally,

you know, the natural arches
that would form in rock.

Agrawal: If you think
about the arch,

you've got this
curved structure,

and when you put a uniform
weight on top of that arch,

the arch basically channels
all of that load

into the bottom of the arch,

but it keeps the entire
structure in compression.

So what that means is
it's being squashed together.

Hutchinson: You take an arch
and just keep on rotating it

and rotating it and rotating it,
you get a dome.

King: Not only is that efficient
for resisting

a uniform downward load, because
it's a three-dimensional system,

it actually has quite
a lot of resistance

to buckling out of shape.

Narrator: The architects choose
a dome for the roof,

but they go a step further
and plan the entire structure

to be contained in the dome.

Flowers: As is the case with
anything, with any building,

scale matters.

So sometimes when you do
something that we know well,

but you just do it a lot larger,
the impact really is tremendous.

Narrator: But what about
the weight problem

that a roof of this scale
inevitably poses?

The stadium's first secret lies
underneath its outer shell.

♪ ♪

there are no supporting walls.

The whole building is basically
a roof, a lightweight dome

formed by a number
of gigantic metal arches.

Six steel trusses span
from side to side,

and at 90 degrees to them there
are giant transverse trusses.

Together they hold up
the whole roof.

♪ ♪

agrawal: Trusses with
lattice structures

are structural engineers'
favorites,

because they've got
triangles in them,

and triangles are
really, really stable shapes,

they don't deform.

So if you imagine that
you had a rectangle shape

and if you put kind of
funny forces onto it,

it can deform into a diamond,

but triangles
just don't do that.

Narrator: There are over
11,000 tons of steel

in this monumental structure.

But in 2008,
when the design team

are still drawing up plans,

the global financial crash
takes its toll

and steel prices rise, all too
aptly, right through the roof.

King: When we initially did
the design of this,

we had almost double the amount
of steel that was in the roof,

and then as steel prices
escalated,

then there was a real drive

to say, okay, how can we
drive efficiency into this?

Narrator: To stop the project
going way over budget,

the team urgently needs
a revised design.

Lewis: Our design mantra was
to reduce weight everywhere

in the structure of that dome,

so we got the best, most
efficient shell structure.

Everything had to be optimized
to a minimum weight

to make that a very
efficient dome.

Narrator: They create
an innovative computer program

that can work out
the minimum amount of steel

that would still meet
the structural requirement.

Lewis: We developed a very
bespoke piece of software

to achieve optimization
of every element

within that roof structure,

whether that was
the thickness of the steel

or the diameter of the tube,
it was all optimized

to make it the lightest
steel structure possible.

King: 20, 30 years ago,
you just couldn't do that.

It would take you years
to do the sort of design

that we've done here
in a matter of months.

Narrator: The result is
a world record-breaking dome

that is so large,

the sydney opera house
would fit inside it.

King: All of the sections
are hollow,

so they're all hollow
tubular sections,

so you make them as thin
and as light as you can.

You're up here and you're
looking at it in various angles,

and everything just looks right
and it looks in balance,

because everything is here
for a reason.

Narrator: Reducing
the amount of steel

cleverly saved the budget
going bust

before construction
had even started.

King: If you took all
of the steel in the roof

and you melted it down

and laid it down on the
footprint of the building,

you'd only have
15 millimeters of steel.

Agrawal: The structure
that makes it up

looks really light
and elegant and slender,

so I think it's, you know,

a real marvel
of structural engineering.

Narrator: One challenge down.

But the roof design
is just the start.

Making it hold its own weight
is one thing,

firmly attaching it to
the ground is quite another.

Narrator: When the high-tech
singapore national stadium

was built, the construction
team faced a serious problem.

The local terrain was
completely unsuitable

for erecting
a large, heavy building.

King: Because
it's reclaimed land,

directly underneath the grass
and the topsoil here,

we have a lot of
what's called marine clay,

and marine clay is about as
useful as dark gray toothpaste

to build a building on.

It really is just muck.

If you were coming
down onto rock,

the force from the dome could
go directly into the rock.

We don't have
that advantage here.

Narrator: The poor ground
threatened the whole project,

but there was a clever solution
right in front of them.

King: We started with the
demolition of the old stadium

here in late 2010.

The old stadium was crushed up.

Lewis: All of the concrete
was used as either a base

or some parts of the ground
forming for landscape.

Narrator: And on top
of that debris,

a rock solid base of concrete.

Hutchinson: The singapore
stadium is built off

what is called
a raft foundation.

Now, that is a large
concrete slab over the ground.

Narrator: Unfortunately,
the raft foundation alone

is not enough.

The dome's weight pushes out
as well as down.

It would collapse
into a giant pancake

unless something holds it in.

Once again, the engineers look

to historic masters
for inspiration.

Hutchinson: In the historic
domes, like florence cathedral

or st. Paul's, is a chain,
a metal chain.

So you put a metal chain
around the edges,

so where all the weight
of the dome comes down

and is trying to pull out,
it's restrained.

Narrator: Engineers stole
that renaissance concept

and came up with what's known
as a ring beam.

Instead of using
a chain above ground,

they buried it
in the foundations.

Hutchinson:
In the singapore stadium,

the dome is restrained
at the edge by steelwork

that it must be
completely continuous,

as if it were a chain,
to stop the dome pushing out.

It relies upon being
one structure

with complete,
undamaged integrity.

King: So what I'm standing
on the edge of at the moment

is the ring beam,
and it contains 14 ducts

of very high-strength
steel cables,

and those cables, the amount
of force that we put in those,

we've pre-stressed them,
is around 4,000 tons.

So it's a huge amount of force.

The ring beam is like a large,
very strong, elastic band

that's pulling it back in

so that all those legs
don't spread.

Narrator: Most critical is
where the huge trusses

meet the ring beam.

A single error here, and
the trusses would explode out.

♪ ♪

king: So these are some of the
most complex and nerve-racking

parts of the project
to construct,

and we call them
the thrust blocks.

So the entire roof,
which is 9,000 tons of steel

and around 15,000 tons
total weight,

comes down on only 20
of these supports.

So you can imagine how
hard they're working.

Narrator: The weight
of the whole structure

is directed down onto
these huge thrust blocks.

The only way to understand

how they're locked
onto the ring beam

is to look inside one of them.

Hidden within the giant
concrete block is the secret.

175 metal rods
called shear keys

penetrate right into the heart
of the ring beam.

Their length and diameter
perfectly calculated

to be just enough to completely
secure the truss.

King: Bringing this down,
just to get 175 shear keys

to sit inside
that reinforced mat,

was one of the most challenging
elements of the whole job.

Narrator: The next aspect
of the project

is where the real
headaches start.

The pitch is made
of live grass,

which leads to another
complex engineering problem.

The enormous roof
has to open and close.

Lewis: The moving roof did pose
challenges for us, you know,

quite commonly they're done
on a flatter roof profile,

and they're very linear in their
opening and closing arrangement.

Doing it on a sphere created
some real challenges for us.

Narrator: The moveable sections
each cover 100,000 square feet,

and because they're curved,

getting them to move at all
is a mechanic's nightmare.

King: The retractable roof is
around 1,000 ton per leaf.

There's two leaves
that open and close.

So the roof had to be
very strong and very stable.

Narrator: The design was
for the moveable leaves

to run on rails,
but there was a dilemma.

Any expansion or contraction
of the metal components

could make the panels jam.

So they couldn't be too rigid.

King: We worked out very early

that we should have
a very stiff, fixed roof,

but then kind of
a floppy, retractable roof

that could kind of bend
and move a little bit.

Steele: The solution that
engineers ended up using

was an incredibly efficient
winch system,

with winches mounted
on that retractable roof

to reduce the amount of cable
that was required.

♪ ♪

♪ ♪

♪ ♪

♪ ♪

♪ ♪

♪ ♪

aaron wong:
When you are wheeling in,

it pulls the roof
upwards to close.

When we are lowering the roof,
the majority of the lowering,

the work is done
by sheer gravity.

Narrator: The roof panels
are mounted on rails

attached to the arched trusses.

Powerful winches on the base
of each panel heave them up

to close the roof,

and the cables take the strain
when it opens.

But here's where
it's really smart.

Sensors monitor exactly
where the panels are,

preventing them
from ever skewing

more than an inch and a half.

And to reduce friction,

the number of wheels in the
system is kept to a minimum.

King: If we reduce
the number of points

that it actually hangs from,
or the driving points,

then that will also
reduce the possibility

of the whole thing jamming.

Wong: This silver-looking strip
is like a barcode,

and the position sensor actually
reads off this silver strip

to inform back to
the event control room

where the control system is,

on the position of the roof
at any one point of time.

So this is tracked very closely.

And one fun fact is that
it's so sensitive

that even a drop of water

would actually cause
the entire system to stop.

Narrator: The retractable roof
is a key feature

of the stadium.

Incredibly, it can open
or close in just 20 minutes.

Thanks largely to lightweight
inflatable pillows

of plastic called etfe,
which make up its skin.

Sean de rozario: Basically,
all aspects of the roof movement

is actually controlled here
from the event control room.

We've already done
our last checks,

mission control is good to go,
and we hit the button.

♪ ♪

♪ ♪

♪ ♪

♪ ♪

wong: Operating such
a huge structure,

it's better to have
as little heavy elements

as possible as we can.

One primary reason why
it needs to be inflated

is to allow water to run off, so
that it is not a flat surface.

If it's flat, water can collect,

or if it's sagging,
water can collect.

♪ ♪

narrator: Today the maintenance
team are out, using a drone.

Wong: We're actually flying
above and outside of the stadium

because we actually
get to go to places

where even
the remote access technicians

would have great
difficulty getting to.

So over there we are
actually able to scan

the entire outer shell, outer
dome of the stadium itself.

♪ ♪

king: If you're in the tropics
or you're equatorial,

like we are here in singapore,
and you're coastal,

then you have salt in the air,

you have a hot,
humid environment,

things rust very, very quickly.

De rozario: So with the drone
we are actually able

to go up there, start to inspect
for things, see whether there,

let's say for example, are there
any abnormal rust streaks

coming down from the roof?

Are there any panels
that look misaligned?

Is there anything that
really looks off?

♪ ♪

♪ ♪

on occasion when
the pitch is in,

we actually use it to monitor
the quality of the pitch

and to actually see how well
the grass is growing

on a frequent basis.

Narrator: Keeping a vigilant
eye on the state of the turf

is vital for any venue that
holds world class soccer,

rugby or cricket events.

But for the singapore stadium,
it's now especially important,

because soon after
the pitch was planted,

there was a disaster.

Steele: Unfortunately there
just wasn't enough light

getting into the stadium,
and the grass, it died.

Narrator: The singapore
national stadium

is one of the most high-tech
sporting arenas in the world.

But when it opened, it had
serious teething problems

with one vital component:

The turf.

Jonathan teo:
In any sports stadium,

the pitch would be
the crown jewel,

because this is where all the
football action, rugby action,

all those events or activities
happen here,

and you have a full house
of 50,000 people watching.

So I would say the pitch
would be most important.

Steele: One of the huge
challenges building a stadium

like this is that you've got
a living thing at its center,

this huge lawn
that's got to be kept

in absolutely tiptop condition

for international
sporting events.

Jin teik: Because we are located
in a tropical zone,

because we have
a retractable roof,

it is not so simple to just
grow grass in this climate.

Teo: So the five key elements
of growing grass:

You need light, water,
temperature, air,

and of course nutrients.

So, to keep this grass healthy,

these five elements
are important.

In a dome where we have
shade and all that,

first of all,
the light is compromised.

Steele: When the stadium opened,
disaster struck.

At the center, the crowning
glory of this stadium

is its beautiful, flat,

international quality
grass pitch.

But unfortunately there
just wasn't enough light

getting into the stadium,
and the grass, it died.

Narrator: More than
an embarrassment,

the withered grass threatens

the fundamental viability
of the stadium.

Detractors called it
a white elephant,

a colossal waste of money.

Footballers like carlos tevez
are prevented from playing

on the substandard turf.

Steele: When it got to the point
that managers weren't allowing

their star players
onto the pitch

for fear that the terrible,
sandy condition of it

would cause them injuries,
something had to be done.

Jin teik: In initial days we
used the stadium growth lights

to enhance the exposure
of light.

Steele: This problem with
the grass was so fundamental

that they tried
everything to solve it,

and they spent
a phenomenal amount of money

trying to just blast this grass
with artificial light

to help it grow.

Narrator: But the light
isn't the problem.

The grass still stubbornly
refuses to grow properly.

Desperate for a solution,
they take a major gamble

and commission
a brand new type of turf.

Teo: We are now currently
at the nursery

where I grow all my grass,
my pitches.

This is where I do all the work,
the start of the journey,

before all the grass rolls
get all rolled up

and go into the national stadium
for events.

Narrator:
At an offsite location

away from the stadium,

jonathan and his team
of horticulturalists

experiment with
different types of grass.

Teo: To some point, my family
actually finds it quite queer

and sometimes funny, what I do.

I get out very early
in the morning

and I come back when
the sun is setting,

and they do wonder what I do.

Until I take them to the park
and I explain to them

the different grass types
and how is it maintained,

and they go, wow!

We are doing
a traction test here,

and this is a portable
traction tool,

and as it rotates, you have
a reading on the wrench here,

and the time when we stop

is when we hear the grass
almost tearing,

and we look at the reading
from here.

So a good traction
would be about 40.

So this is what we're
trying to achieve

to get it ready for
the national stadium.

Narrator: Eventually they
choose a brand-new hybrid turf

that is part real grass
and part synthetic fiber.

Teo: This is the section of the
turf rolls of the hybrid system.

It's reinforced turf,
as you can see,

there's some fibers that's
intertwined with the turf grass.

Of course, the grass matters
a lot as well.

It's just a combination of both,
that's why it's a hybrid.

Narrator: The big advantage
of the nursery

is that spare pitches
can be grown here

and transported to the stadium
whenever they're needed.

The hybrid turf has
7% synthetic fibers

mixed in with live grass

to give the cutting-edge
playing surface consistence.

A layer of high-grade sand
aids traction,

but it's a special
woven backing

that holds both roots
and fibers together.

A network of subsoil pipes
supplies the pitch with water.

Teo: The irrigation system
is fully automated.

I have a computer system
in the office

where I can do my work
and control it.

I can have a remote
to control it,

and as well as an app
on my mobile phone,

that I can control it while
I'm having breakfast, yeah.

Jin teik: In the past one year,
it's been very positive.

We get definitely a sense
of satisfaction,

of saying, okay, this strategy
is working, it's coming along.

But then again,
there is never complacency,

because we are dealing
with a natural product here.

Narrator:
The removable pitch is known
as a lay and play surface,

and for the singapore stadium,
it offers up an added bonus.

Teo: We have pretty much
a multi-events calendar

where we've got sporting,
we've got community events,

so because of this, the lay and
play solution was approached,

and it works out
very well for us.

Narrator: They can change
the pitch in just 48 hours.

But whatever the event,

there's one issue that
always needs addressing:

How to prevent spectators
sweltering

in singapore's
super-hot temperatures.

Narrator: Singapore lies
just one degree north

of the equator, its tropical
climate unforgiving.

Humidity is
consistently over 70%,

and the temperature often soars

well over
80 degrees fahrenheit.

To avoid the spectator
experience being compromised

by the extreme heat, the
national stadium's engineers

must provide cooling
on an enormous scale.

Flowers: Imagine the biggest
room in your house,

we're talking about something
thousands of times larger.

You know how hard it is
to heat and cool that room.

Imagine trying to do it
at a stadium of this scale.

Hutchinson: Quite clearly
you can't condition the air

from the top and blow it down,

because it will just
heat up again.

One of the essentials about
any form of heating or chilling,

you don't want to heat
or chill a space,

you want to heat
or chill people.

Steele: Rather than
air conditioning

the whole enormous volume
of the stadium,

what the engineers came up with

was a per seat
addressable system.

Narrator: Remarkably, cooled
air is blown individually

to every member of the crowd
from below.

Lewis: The air is being,
is being pushed out

through, below the seats,

and you're getting the effect
of that as blanket of cold air,

local to the seating tier,

not trying to cool the whole
volume of the stadium.

Narrator: Pull out the seating,

and there is an intricate
labyrinth of tunnels.

Ducts that send cool air

to outlets beneath
every single seat.

Randall lim tse hsiang: So using
the concept that hot air rises

and cold air sinks, we are able
to keep the cool air

in the stadium by pushing
through the seat outlets

and downwards
to all the audience.

If you put your hand here, you
can actually feel the cool air

coming out from the seats.

Narrator:
It's a brilliant idea,

but the ducted air still needs
to be cooled somewhere.

Lim tse hsiang:
We have 160 air handling units

located at the back of house

that provide cool air to all the
individual seats in the stadium.

Narrator: Warm air
from the atmosphere

draws into these giant
heat exchangers

where it meets cold water.

Lim tse hsiang: Behind me are
the chiller plant room,

producing chilled water,

and once this chilled water
leaves the plant room,

it travels through the pipes
to the individual air chutes,

air handling units
they're so called.

Narrator: The challenge here
is how to produce

very large quantities
of cold water on demand.

Steele: So one of the solutions
they've come up with

is to use loads and loads
of balls of glycol,

so basically antifreeze,

which you cool down to a very
low temperature before a game,

and that means that you
can use them to store up

all that cold in readiness
for the big event.

Narrator: Glycol works
like the ice packs

we put in the freezer;
it retains cold.

Agrawal: The night
before a big match,

they'll cool down the glycol,

which in turn can
cool down the water,

and then this water will cool
down the warm and humid air

which is then circulated
out into the stadium.

Narrator: Once the cooling
is achieved,

the water simply recirculates
through the system.

♪ ♪

when the singapore national
stadium was conceived,

one of the most
demanding directives

was that it should be
a multiple function area.

Like no other stadium on earth,
it must host soccer, rugby,

cricket and athletics,
as well as rock concerts.

Each kind of event needs
a different-sized area,

but for all of them,

spectators need to be as close
to the action as possible.

Steele: The only way
to make sure people

are right at the forefront
of the action

in loads of events with
very different configurations

is to allow the seating stands
themselves to move.

The first thing that happens is
that middle tier retracts

downwards, and then the front
tier of seats can move back,

covering those up and
making a bigger space

in the middle of the stadium.

Lewis: There's 30,0000 seats
that move.

In athletics mode,
they drop down to the ground

and they're tucked under
the retracted seats,

and there's about 5,000 seats
that appear in football mode.

Narrator: The tiers weigh
up to 1,500 tons each,

so this is an incredible
feat of engineering.

Hidden underneath
the seating bowl

is a state-of-the-art
lift system.

Lewis: That's called
a serapid machine.

It's a chain-driven machine
that crawls around in a trench.

Narrator: With the help of this
machine beneath the tiers,

the stadium's capacity
transforms 50,000 to 55,000.

And for both configurations,

designers have maximized
the spectator experience

by scientifically designing
the acoustics.

Narrator: In public arenas,
spectators demand excitement.

They want a high-volume assault
on their senses.

Lewis: It's always
about creating

the unforgettable experience
for spectators.

In the singapore's national
stadium we have achieved

something really special
in terms of atmosphere.

Narrator: An important aspect
of that experience

comes from
the stadium's acoustics.

(cheering)

hutchinson:
You want it to be noisy.

If you're cheering on the reds,

you want to hear everybody else
cheer on the reds,

and the louder the noise,
the better.

(cheering)

lewis: Acoustics are
incredibly challenging,

because you're dealing with
the different types of events,

so you're dealing with concerts,

you're dealing
with soccer events.

You're dealing with different
capacities within the venue,

so you have to design
for absorption

on people being in the bowl, or
how the sound will be reinforced

within that atmosphere.

Narrator: Here in singapore,
sound engineers applied

rigorous science to the choice
of materials for the roof.

Anything that would absorb
sound, like soft curtaining,

was rejected.

Steele: You want to hear that
crowd magnified, amplified,

and so in the singapore stadium
they've got loads and loads

of highly sound-reflective
surfaces that bounce that sound

back at all angles to try
and make everything sound

as loud and intense
and vibrant as possible.

Xu jingfeng:
It's very important to have

lower part of the roof
to be reflective,

which can reinforce
this excitement

generated from the crowds.

Narrator: Today jingfeng is
running a test to determine

if those reflective metal
and plastic surfaces

are still performing
as intended

throughout the stadium.

Jingfeng: We're going to play
a special test sound

to check the frequency
distribution

at each receiver location,

as well as how evenly the sound
level is across the stadium.

The special sound that we're
going to play is pink noise,

which is a flat sound
across the overall spectrum.

Narrator: Pink noise is sound
that's evenly spread

between low and high
frequencies.

If the monitor shows
a flat response,

it means the space
is reflecting

all frequencies equally.

Any drop-off shows that
frequency is being absorbed.

The results are
all pretty flat.

Good news.

♪ ♪

♪ ♪

(cheering)

when a stadium is
at full capacity,

it is particularly vulnerable,

and that means crowd management
has to be at the very center

of every design decision.

King: And when the game's done,
everyone's out, you know.

So it's 55,000 people
want to leave now.

Modeling that
so that you understand

how people can do that
comfortably and leave

and get to the various
transport facilities

within a reasonable time frame
and comfortable and safely,

is absolutely critical.

Narrator: The price paid
when things go wrong

is the heaviest imaginable.

Agrawal: In a stadium,
when it's full,

you've got tens
of thousands of people

all in there at the same time,

and we know that we've had some
really devastating disasters

in the past, whether
it's hillsborough or heysel.

Narrator: At both tragedies,
critical errors compounded

and people were
crushed to death.

And if fire takes hold
at a stadium

with poor exit planning,

the results can be
equally shocking.

Hutchinson: And we saw that to
our cost at the bradford stadium

where there was
a terrible disaster,

about not being able
to get people out.

King: Fires in these sorts of
facilities are very, very rare,

but the history in the uk
has shown that they can occur,

and understanding
how people will react

and making sure that they can
react and they can leave safely

in a very short period of time
is critical as well.

Lewis: We've designed
the building so that

the typical scenario is
an evacuation in terms of a fire

or something which requires
an immediate local response,

and for that we have
an eight-minute time frame

in which we're allowed to
take people from their seat

to a point outside
of the stadium.

Narrator: Planning how 55,000
people can quickly evacuate

the stadium is a task where
the architects couldn't afford

to make a single mistake.

Narrator: A life-threatening
emergency at a crowded stadium

is one of the greatest fears
for any architect.

Agrawal: So it's absolutely
imperative that the design

of the structure and
everything that goes around it

is really spot-on
to make sure that we don't have

any devastating
consequences from it.

Narrator: Singapore stadium's
engineers used computers

to analyze crowd behavior

and help them plan
entrances and exits.

King: These things
are amazing to watch,

because you watch where people
crowd and where they congregate

and where you're getting
too many people,

where are the pressure points.

And it's really important to
find where that's going to occur

and then change the design
before you've built it.

Lewis: Part of the design of
stadiums is around ensuring

that every exit, as you
sequentially go to the outside

of the building,
is getting wider,

so you're sequentially able to
flow unimpeded at a faster rate

out of the building.

And a lot of that required us
to make changes to the design,

because some of the widths,
even 10-meter widths,

were required to increase
to 12-meter widths

to allow for counterflow
of people

under the cover of that canopy.

♪ ♪

narrator: The status
of any stadium is defined

by the prestige
of the events it holds.

One of the most impressive

staged at the singapore
national stadium

was the 2015
southeast asian games.

King: That was
a very successful event,

and it really showcased how
the stadium can be best used

for those sorts of events.

That was something where
the people of singapore came,

and really, I think, felt
a wonderful atmosphere in here,

and, I mean, it's their city
on display to the world.

Narrator:
But in this day and age,

even a world class event is
not enough to draw attention.

Flowers: Increasingly stadiums
are urban projects.

They help give
identity to cities,

and so therefore you want them
to be prominent in the skyline

and prominent in the cityscape.

Agrawal: So for me
the most impressive thing

about the singapore
national stadium

is those plastic cushions
at the top that light up

and just give the building
a huge amount of personality.

Right at the crown, at the top
of this beautiful dome,

is this absolutely
startling feature

where they use lights
to project images and videos

which you can see not only
from the inside of the stadium,

but also outside
from the city itself.

George michaels: The fact
that we have a live roof

is very unusual, but it adds
to the enhancement

of the patrons' experience,
and this is what we aim.

We want to give the patrons,
as they're coming in,

they can see a lit roof, and
once they come into the stadium,

it's even a better
experience for them.

King: When there's a goal
and it says "score" and "goal,"

and it flashes from
one side to the other,

and there's all this rock music
and everything going on,

it just really
pumps up the crowd,

and that's important
for the stadium,

for the stadium
to be successful,

but also how it's conveyed on tv
for viewers at home.

Agrawal: So in order to create
this really impressive display,

they've used
tens of thousands of leds

on the retractable
portion of the roof.

Narrator:
The vast screen is one of
the largest in the world.

And because it's made of leds,

it draws comparatively
little power.

It's the final piece
in this high-tech puzzle

and cements the stadium's
high profile.

Not only is it the largest

free-spanning dome
in the world,

it's prevailed against
all its detractors

and become a triumphant

sport, entertainment and
economic success story.

Flowers:
Stadiums are so expensive,

in part because they are among
the most profitable buildings

you can build.

Essentially a stadium is
a machine for making money,

which is what we used
to call skyscrapers.

But I really think stadiums
have supplanted skyscrapers

as the penultimate--

no, the ultimate 21st century
machine for making money.

Narrator: Against the odds,
the singapore national stadium

has overcome the problems

of building on soft,
reclaimed land,

it has a roof
of unprecedented scale,

and extraordinary engineering
enables its seating tiers

to be transformed on demand.

Jin teik: I think the emotional
part is that it's come true.

It's a dream come true,

it is one that is,
it will transform our lives.

Lewis: Just an amazing venue
which we, as a team,

are just incredibly proud
to see open,

and it is about an integrated
approach to architecture,

design, with engineering,
to achieve what we've achieved.

♪ ♪

♪ ♪

captioned by
side door media services