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in today's impossible engineering.

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This must be one of the most complex
engineering projects ever undertaken.

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The world's largest free -spanning dome.

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The Singapore National Stadium is really
a marvel of engineering.

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You put 65 ,000 people in a place like
this, it's pretty fabulous, really.

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Stadium engineering on an extraordinary
scale.

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9 ,000 tons of steel was used to carry
this roof above me right now.

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And the pioneering historic innovations.
Here we are, up on the roof.

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It's huge.

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It's actually disorientating to see the
dome rotating.

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It's truly impressive.

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That made the impossible possible.

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Singapore is the second most densely
populated country on the planet.

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with about 5 .7 million people spread
over 281 square miles.

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This presents unique challenges for
engineers designing something as massive

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an athletic stadium.

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We need a facility to enable us to host
world -class international sporting and

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entertainment content.

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At the same time, it has to be multi
-purpose given our land constraints and

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need to optimize every available acre of
land.

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But in Singapore's tropical
environment...

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space to build isn't the only problem.

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So we are one degree north of the
equator, which means that we are warm

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humid, and we have rainfall almost one
-third of the year.

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So the stadium has to provide protection
against the weather.

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To take on this colossal challenge,
engineers have created a structure like

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other on Earth.

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This is the Singapore National Stadium,
a gigantic

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multi -purpose sports arena.

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Eight enormous arches create a 270 -foot
-high freestanding shell with enough

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space inside to contain the Sydney Opera
House.

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50 ,000 spectator seats can be increased
to 55 ,000. by an advanced

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reconfiguration system.

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And at the push of a button, two
gigantic roof leaves, each 107 ,000

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feet in size, will close to protect from
Singapore's turbulent weather

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conditions.

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The largest free spanning dome the world
has ever seen marks the dawn of a new

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age of superstructure.

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I think the engineers have achieved
something which is truly incredible.

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Everything from the smallest boat to the
entire free -spanning dome is a work of

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wonder.

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It's a huge achievement in terms of
engineering and design solutions, and

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all about integration of architecture
and engineering working together.

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It's up to Stadium CEO Lionel Yeo to
oversee this one -of -a -kind arena.

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Well, think about the scale of the
project.

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You have a dome which is this size, 310
meters wide, 82 .5 meters high.

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I think it is an engineering marvel.

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It's a very complex project.

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The domed roof in particular makes this
stadium a unique challenge.

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And engineer Mok Sui Chiang was part of
the team responsible for its

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construction.

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The dome is really a very iconic
structure here in Singapore.

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If you look across the city skyline, you
can definitely see it.

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So 9 ,000 tons of steel was used to
carry this roof above me right now.

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But how have they erected this structure
to stand strong with no columns or

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support?

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The dome wants to flatten out.

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That's the nature of a dome.

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You really need to prevent that from
happening.

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And how do you transform an enormous
stadium to accommodate huge concerts and

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sporting events?

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The national stadium will need to cater
for various events.

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And it's not an easy task to move such a
structure.

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And how can such a record -breaking
structure be sheltered against Mother

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Nature?

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It rains a lot and it rains hard.

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But the stadium's design calls for this
open roof.

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that needed to provide a serious amount
of shading and protect the spectators

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from the rain.

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Engineers knew from the very beginning
that this project would raise numerous

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complications.

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The seating arrangement that was
designed by the architect leaves a very

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space for engineers to design a roof
that covers it.

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With columns, you'll be obstructing the
view of the spectator.

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So it's quite critical to have the
columns removed.

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So to preserve spectator views, the team
has come up with a remarkable form that

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requires no columns at all.

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To support the dome of this scale, the
solution is to have a three -dimensional

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rib truss system.

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What we have here is six runway trusses
that run from left to right.

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And then you have, at 90 degrees, two
transverse trusses running across to

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it up.

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In addition to that, we have diagonal
trusses that connect the corners

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to form a very three -dimensional state
structure that is able to withstand the

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huge load that it's experiencing.

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An arch is one of the strongest shapes
under gravitational load.

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So combining the two transverse arches
with the six runway arches creates a

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three -dimensional arch or dome.

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Once you arrange the trusses in a three
-dimensional way, you really get a very,

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very stable structure.

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It's really the most efficient way to
channel all the forces down.

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During construction, giant cranes
erected the steel truss.

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while 90 temporary pylons supported the
structure from beneath.

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After nine months, the final piece was
raised into position.

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The temporary pylons were removed, and
the truss configuration could finally

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support itself.

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But with the framework in place,
engineers faced another problem.

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The Singapore Stadium, in fact, is built
on reclaimed land, which essentially is

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Singapore marine clay.

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And Singapore marine clay is like
butter.

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It is almost impossible to be supported
on.

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With soft ground and a massive dome
structure prone to flattening out, the

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must turn to the pioneers of the past.

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In Orange County, Indiana,

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architect Todd Rotman is exploring a
site that may hold the key to keeping

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Singapore National Stadium standing.

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This is what started it all, the Mineral
Springs.

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The secret to this area's popularity can
be found in its artisanal waters.

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People thought the water here had
medicinal qualities, so people would

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they would bathe in it.

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And this ended up becoming a playground
for the rich and famous.

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The draw to this area was enough to make
the owners want to build a hotel resort

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that could rival even the finest spas in
Europe.

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Tasked with making this dream a reality
were architect Harrison Albright and

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bridge engineer Oliver Westcott.

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In 1902, they revealed a building that
changed the world of structural

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engineering. Oh, wow.

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That is gorgeous.

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This is the West Baden Springs Hotel.

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It's just so huge. It's amazing.

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And its crowning jewel, a gigantic free
-spanning dome sitting high above the

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atrium.

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At the time, it was the largest dome in
the world, over 130 feet tall in the

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center point, over 200 feet in diameter.

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So what can Singapore Stadium's
engineers learn from this spectacular

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And what keeps it standing over 100
years after its design? What makes this

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amazing is the technology and the
engineering that went into making it

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because it hadn't been done before.

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Creating one of the world's largest
multipurpose facilities requires

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to radically rethink every aspect of
stadium design.

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This is the Singapore National Stadium.

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A record -breaking dome the likes of
which the world has never seen.

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8 .8 million cubic feet of concrete has
been poured into this megastructure,

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creating a 2 .9 million square foot
floor area, large

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enough for an enormous seating bowl,
capable of accommodating 55 ,000

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spectators.

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But to encase this vast arena, engineers
needed to draw inspiration from the

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design of a record -breaking 1902
structure.

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The West Baden Springs Hotel.

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What an amazing view.

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Designers Albright and Westcott
constructed the largest dome in the

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title it held for over a decade.

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But how does it stay supported above the
atrium without a single column?

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So if you look up at the roof, you can
see 24 steel trusses that terminate a

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drum in the middle.

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and extend down and out to the columns
along the perimeter.

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The problem is there's a lot of weight
being pushed out on them.

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So to take that load, pushing out, they
put two steel tension rings around

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the perimeter. So if you look out across
the dome, above and below those windows

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are those tension rings, and those are
structural components that hold this

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building up.

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To demonstrate how the inspired tension
ring beam solution works, Todd has

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scaled it down.

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We've got a simulated dome structure
with the trusses.

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We've got a weight.

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Let's put the weight on it and see how
the trusses hold up.

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So as you can see, the ends of the
trusses kicked out. There was nothing to

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them in place, and we've got a failure.

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Now, if we add a tension ring around the
perimeter of it,

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And we use the exact same trusses.

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Let's see how the tension ring helps.

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No failure.

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It's able to support the weight.

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And we can even put additional weight
and it still holds it.

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The tension ring is taking all of that
lateral force, it's containing it, and

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making all of the load go straight down.
So imagine the innovation of making one

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out of steel and supporting a 200 -foot
diameter dome. It's a simple concept,

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but used in a big way.

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Albright is rumored to have been so
confident in the dome's design that he

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on top of it as the construction
supports were removed.

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To get a closer look, Todd is braving
the climb to an area very few people

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get to see.

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All right, here we are, up on the roof.

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Yeah,

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but this isn't our final destination.

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At the very apex of the dome, its
trusses are tied together in a central

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structure, suspended high over the hotel
lobby.

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All right, so this, to me, is a little
bit more scary than being on the roof.

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These boards date back to 1901.

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You know, this is kind of where the
structure starts, right? This is where

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all comes together, and from here the
forces go out down the trusses to those

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tension rings.

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With the world's largest free -spanning
dome as its showpiece, the hotel

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attracted visitors from around the
world.

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More than a century later, the domed
roof has stood the test of time, thanks

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its ingenious tension ring support.

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To build this magnificent structure with
such a large dome, it's just a

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testament to the incredible engineering.

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It's truly awe -inspiring.

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Here we are today, over 100 years later,
the same structure is in place, still

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standing tall, just as beautiful as it
ever was.

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In Singapore, engineers have taken the
same concept and supersized it.

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The only way to hold a record -breaking
dome together is with the planet's

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largest tension ring beam.

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So the ring beam is positioned below the
transverse, and it is actually

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somewhere behind these walls.

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The ring beam is 6 meters in width and 1
.5 meters in depth.

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Taking six months to complete, the
gigantic concrete ring has a

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over half a mile encircling the stadium.

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350 ,000 cubic feet of concrete is
reinforced by 14 steel tendons, which

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threaded through the ring beam and
tightened.

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squeezing it in towards the center like
an elastic band.

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As the weight of the dome tries to
spread out, the ring beam pinches back

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from 360 degrees, holding the structure
in place.

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Buried in the foundations is the largest
ring beam in the world.

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But above ground are the final
components that tie the system together.

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So the forces from the arches actually
come down the truss and then hit the

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truss block.

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And there are about 20 of these truss
blocks around the length of the ring

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The truss block will transfer the forces
down to the ring beam.

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And there's a lot of things happening at
the truss block.

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Forces in all directions will interact
and work the truss block quite hard.

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175 metal studs tie the foot of each
arch to the thrust blocks reinforcing

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rods.

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Transferring the force of the dome's
weight into the ring beam and holding it

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firmly in place.

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120 years since West Baden held the
record for the world's largest dome.

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Singapore has taken that mantle with a
structure Albright and Westcott could

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have only dreamed of.

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So the ring beam is actually a very
crucial and clever idea to withstand the

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forces coming down from the dome.

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But with the domed roof held firmly in
the ground... It takes more impossible

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engineering to turn this shell into a
world -class venue.

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And Singapore's tropical climate means
additional challenges.

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It's hot and humid all year round.

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It's 33 degrees, 34 degrees every day.

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You put 55 ,000 people in a place like
this, you basically raise the

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by about 3 degrees.

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Spectators are sticky, it's
uncomfortable.

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When you sit through a two -hour show,
it's a chore rather than enjoying the

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event. But the roof is 80 meters high,
20 stories.

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It's a large volume.

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You can't cool all of that space.

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Instead of attempting to chill the
enormous room, engineers came up with a

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creative solution.

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00:17:31,370 --> 00:17:34,670
We can cool the venue much more energy
efficiently from below.

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00:17:35,010 --> 00:17:38,950
So we deliver cool air at around 23
degrees, just under the seat.

238
00:17:39,650 --> 00:17:42,450
So we create a comfort zone, a bubble.

239
00:17:43,470 --> 00:17:48,690
But to deliver localized cool air to
each seat, it first needs to be chilled

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00:17:48,690 --> 00:17:50,930
a subterranean climate control system.

241
00:17:53,790 --> 00:17:55,310
This is the heart of the system.

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00:17:55,510 --> 00:17:58,070
We're producing chilled water in here at
8 degrees.

243
00:17:58,290 --> 00:18:00,290
We push that chilled water out to the
stadium.

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00:18:00,510 --> 00:18:04,390
It goes through an air handling unit
associated with each zone of the bowl

245
00:18:04,390 --> 00:18:05,390
cooling system.

246
00:18:05,410 --> 00:18:10,190
The chilled water arrives there at 8
degrees. We pass air across a cooling

247
00:18:10,390 --> 00:18:12,090
provides the cooling to the seat.

248
00:18:13,770 --> 00:18:18,190
But huge events filling the whole
stadium require a cooling system that

249
00:18:18,190 --> 00:18:19,530
handle the high capacity.

250
00:18:22,250 --> 00:18:25,190
Deep in the subcellars are four tanks.

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00:18:27,790 --> 00:18:33,550
Each one contains 300 ,000 glycol balls,
a material chosen for its thermal

252
00:18:33,550 --> 00:18:34,550
storage properties.

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00:18:36,410 --> 00:18:41,350
These balls are frozen so that as water
flows through, it is chilled before

254
00:18:41,350 --> 00:18:43,170
being delivered to the seating
galleries.

255
00:18:43,580 --> 00:18:49,500
and then re -chilled as it is recycled
through the system, meaning it's more

256
00:18:49,500 --> 00:18:51,260
than able to cool a full house.

257
00:18:54,180 --> 00:18:57,880
It's pretty fabulous, really, when you
think we can sit here and we can air

258
00:18:57,880 --> 00:18:59,680
-condition 55 ,000 seats.

259
00:19:00,140 --> 00:19:03,960
We put the spectators in a space which
is really quite enjoyable. You can sit

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00:19:03,960 --> 00:19:06,120
here for 10 hours in a day and you not
raise a sweat.

261
00:19:08,520 --> 00:19:11,840
But this tropical country is also short
on space.

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00:19:13,480 --> 00:19:17,960
Randall Lim's team of engineers face
another challenge to minimize the

263
00:19:17,960 --> 00:19:19,500
of a multipurpose arena.

264
00:19:21,260 --> 00:19:25,040
We have events ranging from track and
field to concerts to football.

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00:19:25,360 --> 00:19:29,380
For football events, you want to be
seated as close as possible to the

266
00:19:29,880 --> 00:19:33,460
And then for track and field events, you
want to be seated as close as possible

267
00:19:33,460 --> 00:19:34,820
to where the runners are.

268
00:19:35,200 --> 00:19:39,840
For a typical stadium where you have the
pitch surrounded by the track, you

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00:19:39,840 --> 00:19:42,220
could be as far as 15 meters away.

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00:19:43,950 --> 00:19:49,370
It is crucial to find a solution to
design a stadium that caters for various

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00:19:49,370 --> 00:19:50,370
events.

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00:19:51,110 --> 00:19:56,070
To provide the optimal spectator
experience, regardless of the event, the

273
00:19:56,070 --> 00:19:59,190
must look to another iconic stadium for
inspiration.

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00:20:05,810 --> 00:20:09,630
It may not seem obvious at first because
of the size of the stadium, but this

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00:20:09,630 --> 00:20:10,650
place can actually move.

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00:20:11,340 --> 00:20:16,020
To build a versatile arena like no
other, the team behind the Singapore

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00:20:16,020 --> 00:20:20,720
Stadium will need to take the
innovations of the past and supersize

278
00:20:21,580 --> 00:20:27,340
So in total, we have eight sections, and
that gives us over 24 ,000 teams to

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00:20:27,340 --> 00:20:28,340
shift.

280
00:20:32,240 --> 00:20:38,800
Engineers have created the Singapore
National Stadium, one of the largest

281
00:20:38,800 --> 00:20:40,700
and entertainment venues on earth.

282
00:20:45,000 --> 00:20:50,860
The colossal roof encases over 100
million cubic feet of completely open

283
00:20:52,020 --> 00:20:56,820
That's enough room for the arena to be
filled with water from 1 ,200 Olympic

284
00:20:56,820 --> 00:20:57,820
swimming pools.

285
00:21:02,000 --> 00:21:07,340
But to succeed as a multi -event venue,
this stadium needs to have structural

286
00:21:07,340 --> 00:21:13,070
versatility. To achieve this monumental
goal, Engineers will look to the

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00:21:13,070 --> 00:21:14,530
pioneers of the past.

288
00:21:19,590 --> 00:21:22,010
It's so beautiful here. I love living in
Hawaii.

289
00:21:23,250 --> 00:21:26,090
Engineer Kenan Koga is searching for the
answer.

290
00:21:27,170 --> 00:21:30,350
Having this awesome weather here and
great environment, it makes a lot of

291
00:21:30,350 --> 00:21:33,290
for Hawaii to try to host a lot of
different sporting events, but there's

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00:21:33,290 --> 00:21:34,650
lot of space here to actually do that.

293
00:21:35,390 --> 00:21:37,910
On an island where space to build is
limited.

294
00:21:38,360 --> 00:21:41,400
Sports fans need one venue to serve all
purposes.

295
00:21:43,900 --> 00:21:48,960
A football field is a rectangular shape,
and a baseball field is a diamond

296
00:21:48,960 --> 00:21:53,660
shape. So if you're watching a football
game in a baseball stadium, the fans way

297
00:21:53,660 --> 00:21:57,960
out here in left field can't see the
action happening on the football field

298
00:21:57,960 --> 00:21:58,960
here.

299
00:22:01,240 --> 00:22:03,000
Charged with finding a solution,

300
00:22:03,720 --> 00:22:06,260
architect Charles Luckman hit a home
run.

301
00:22:08,460 --> 00:22:13,360
In the 1970s, he came up with a design
that would change the world of stadium

302
00:22:13,360 --> 00:22:14,360
engineering.

303
00:22:15,980 --> 00:22:17,320
Well, here we are, guys.

304
00:22:20,360 --> 00:22:22,560
This is the Aloha Stadium.

305
00:22:24,040 --> 00:22:25,640
This place is massive.

306
00:22:26,740 --> 00:22:31,260
An enormous superstructure,
affectionately known as the Metal Mecca.

307
00:22:31,920 --> 00:22:36,100
You can just imagine this whole place
packed with fans, everybody.

308
00:22:36,720 --> 00:22:39,580
cheering, stomping all over the stadium,
feeling it shake.

309
00:22:42,240 --> 00:22:46,040
And it may not seem obvious at first
because of the size of the stadium, but

310
00:22:46,040 --> 00:22:47,260
this place can actually move.

311
00:22:49,660 --> 00:22:54,020
The curved sections at the far ends of
the field would remain permanently

312
00:22:54,020 --> 00:22:58,660
in place, but the flanking seats divided
into four sections could pivot to

313
00:22:58,660 --> 00:23:05,500
create an open -sided baseball diamond
or a closed rectangular football field.

314
00:23:07,150 --> 00:23:11,050
So if you can imagine, this is where the
stadium would part like the Red Sea and

315
00:23:11,050 --> 00:23:14,270
move in a given direction. If someone
didn't tell you that these sections

316
00:23:14,270 --> 00:23:15,390
move, you would never know.

317
00:23:16,310 --> 00:23:22,110
But to shift 28 ,000 seats weighing over
6 ,000 tons was a huge task.

318
00:23:24,070 --> 00:23:25,070
Watch your head.

319
00:23:25,710 --> 00:23:30,270
So Luffman installed innovative devices
underneath the stadium to make the heavy

320
00:23:30,270 --> 00:23:31,670
stands float on air.

321
00:23:32,080 --> 00:23:35,500
So underneath each one of these beams,
you had an air skate, which is

322
00:23:35,500 --> 00:23:37,060
essentially like a little balloon.

323
00:23:37,480 --> 00:23:41,980
The compressed air is filled through
this line up here and funnels down and

324
00:23:41,980 --> 00:23:43,580
distributed to each one of the air
skates.

325
00:23:43,960 --> 00:23:47,720
That balloon fills up and there's a box
around that balloon that allows the

326
00:23:47,720 --> 00:23:51,080
compressed air to funnel directly down
and push this piece up.

327
00:23:52,820 --> 00:23:58,740
To move this colossal structure, 416 of
these air skate discs are distributed

328
00:23:58,740 --> 00:23:59,740
across the stadium.

329
00:24:01,990 --> 00:24:06,250
Feeding them with a constant flow of air
pressure creates a thin, frictionless

330
00:24:06,250 --> 00:24:11,570
film between the skate and the ground,
requiring the force of only one pound to

331
00:24:11,570 --> 00:24:13,330
move 1 ,000 pounds of weight.

332
00:24:16,890 --> 00:24:18,950
And to see this concept in action,

333
00:24:19,690 --> 00:24:21,570
Keenan has taken up another sport.

334
00:24:22,250 --> 00:24:24,390
So here we're trying to illustrate the
actual stadium.

335
00:24:24,730 --> 00:24:28,010
When the air hockey table is off,
there's a greater amount of frictional

336
00:24:28,010 --> 00:24:29,890
between the table and the stadium.

337
00:24:30,380 --> 00:24:33,380
So to remove the human factor of the
amount of force that I could actually

338
00:24:33,380 --> 00:24:37,460
insert onto the stadium, we'll use a
piece of paper here, and we're trying to

339
00:24:37,460 --> 00:24:42,420
move this piece into the stadium, move
it around, change the configuration, but

340
00:24:42,420 --> 00:24:45,100
we can't really do that just because of
the amount of frictional force that's

341
00:24:45,100 --> 00:24:46,140
keeping this piece in place.

342
00:24:46,760 --> 00:24:48,040
I can't move this at all.

343
00:24:49,960 --> 00:24:53,300
But as you can see, when you turn the
machine on, it's mimicking the air

344
00:24:53,300 --> 00:24:57,760
in the stadium, creating a very small
gap between the piece and the surface.

345
00:24:58,080 --> 00:25:00,820
which is decreasing the amount of
surface tension and friction.

346
00:25:01,300 --> 00:25:04,060
So therefore, you only need a small
amount of force to actually move the

347
00:25:04,060 --> 00:25:10,340
stadium. And now we can actually guide
this piece into place similar to our

348
00:25:10,340 --> 00:25:11,340
stadium.

349
00:25:14,960 --> 00:25:20,960
Between 1975 and 2007, the stadium would
be transformed twice a year,

350
00:25:21,480 --> 00:25:25,640
each reconfiguration taking up to two
weeks to complete.

351
00:25:27,210 --> 00:25:32,470
Weighing 14 million pounds, the Aloha
Stadium's movable stands were once the

352
00:25:32,470 --> 00:25:35,230
heaviest load to ever be carried on an
air film.

353
00:25:38,970 --> 00:25:43,530
After 46 years of youth, the stadium's
days are drawing to a close.

354
00:25:44,370 --> 00:25:47,950
It's really quite an honor for me to be
one of the last few people that are

355
00:25:47,950 --> 00:25:50,910
standing here before demolition crews
start to begin work on the stadium.

356
00:25:51,250 --> 00:25:55,450
But thanks to Luckman's initiative, its
engineering legacy lives on.

357
00:25:57,820 --> 00:26:01,680
What they did here is they took a simple
concept and blew it up on an enormous

358
00:26:01,680 --> 00:26:05,800
scale. The concepts applied here have
provided inspiration to so many modern

359
00:26:05,800 --> 00:26:06,860
stadiums around the world.

360
00:26:20,720 --> 00:26:25,480
For the next generation all -purpose
venue, engineers have adapted the Aloha

361
00:26:25,480 --> 00:26:28,580
Stadium's pioneering technique for the
21st century.

362
00:26:33,700 --> 00:26:36,540
But this auditorium doesn't just move.

363
00:26:39,640 --> 00:26:45,560
It can grow its capacity from 50 ,000 to
55 ,000 spectators' beats.

364
00:26:47,630 --> 00:26:52,010
The lower tier, as you see behind me,
will shift outwards towards the pitch

365
00:26:52,010 --> 00:26:56,610
area, creating a void between the lower
tier structure and the building.

366
00:26:56,870 --> 00:27:01,050
And then the concourse platform will be
listed up to fill the void in between.

367
00:27:02,350 --> 00:27:06,230
To transform such a massive structure...
Be careful of the track.

368
00:27:06,730 --> 00:27:09,470
...takes some incredible engineering
solutions.

369
00:27:11,130 --> 00:27:14,150
We are now underneath lower tier
structure.

370
00:27:14,540 --> 00:27:18,840
Each tier weighs around 900 to 1 ,000
tons.

371
00:27:19,300 --> 00:27:23,040
There are 3 ,000 seats in each of the
lower tier sections.

372
00:27:23,340 --> 00:27:28,860
So in total, you have eight sections,
and that gives us over 24 ,000 seats to

373
00:27:28,860 --> 00:27:29,860
shift.

374
00:27:30,580 --> 00:27:34,900
Like the Aloha Stadium, the Singapore
engineers have employed a similar

375
00:27:34,900 --> 00:27:36,460
technique to move their seats.

376
00:27:37,840 --> 00:27:40,400
So these are the front set of loading
points.

377
00:27:40,700 --> 00:27:45,040
Before the shifting, We will slide in
this, what we call the air skid.

378
00:27:46,200 --> 00:27:51,520
Compressed air comes into this
distribution module where we will

379
00:27:51,520 --> 00:27:57,140
compressed air to every single air skid
to lift the structure slightly and also

380
00:27:57,140 --> 00:27:58,660
to reduce its frictional weight.

381
00:28:01,660 --> 00:28:05,700
Reducing the ground friction of these
immense seating tiers allows just a

382
00:28:05,700 --> 00:28:10,560
handful of engineers to push the 1 ,500
-ton structures closer to the action.

383
00:28:13,290 --> 00:28:16,950
leaving a void between the stadium wall
and the seating tier.

384
00:28:19,090 --> 00:28:24,270
To make the most of this additional
space, engineers will need to take

385
00:28:24,270 --> 00:28:28,950
air skate technology and combine it with
even more innovative engineering.

386
00:28:29,430 --> 00:28:33,350
This is definitely a remarkable machine,
even this capability.

387
00:28:35,810 --> 00:28:37,950
At Singapore National Stadium.

388
00:28:38,490 --> 00:28:43,430
Engineers have been inspired by Aloha
Stadium's innovative use of air skate

389
00:28:43,430 --> 00:28:48,710
technology. They've devised a system
allowing just a few people to move

390
00:28:48,710 --> 00:28:50,890
seating sections closer to the action.

391
00:28:52,630 --> 00:28:53,670
Watch your head.

392
00:28:54,010 --> 00:28:58,810
This new configuration leaves room for
an additional 5 ,000 concourse platform

393
00:28:58,810 --> 00:29:04,250
seats. Where we are in now is a trench
that runs across the stadium.

394
00:29:04,490 --> 00:29:06,450
It's underneath the concourse platform.

395
00:29:07,150 --> 00:29:11,010
And the trash is built for sole purpose
for the concourse platform handling

396
00:29:11,010 --> 00:29:12,010
machine.

397
00:29:13,210 --> 00:29:18,690
This machine will leave the concourse
platform upwards to fill the void

398
00:29:18,690 --> 00:29:19,690
the two structures.

399
00:29:22,850 --> 00:29:27,630
This innovative machine performs like a
scissor lift, but instead of hydraulics,

400
00:29:27,770 --> 00:29:30,090
it's driven by rigid chain technology.

401
00:29:31,710 --> 00:29:35,810
In the lowered position, the flexible
chain is coiled up for storage.

402
00:29:36,720 --> 00:29:41,280
But when driven upwards by the rack and
pinion motor, the chain links lock

403
00:29:41,280 --> 00:29:43,180
together to form a rigid column.

404
00:29:48,100 --> 00:29:53,380
And thanks to even more air skate
technology, this 70 -ton machine can be

405
00:29:53,380 --> 00:29:57,160
by just one person along a track running
the length of the trench.

406
00:30:00,600 --> 00:30:05,140
Meaning only one of these devices is
needed to transform the whole middle

407
00:30:05,140 --> 00:30:06,140
Concorde.

408
00:30:07,600 --> 00:30:13,680
And once in position with the concourse
platform secured, the machine itself

409
00:30:13,680 --> 00:30:18,440
will lower and will move to the next
location to perform another shift.

410
00:30:19,640 --> 00:30:26,080
This is definitely a remarkable machine,
given its capability to raise up to 95

411
00:30:26,080 --> 00:30:29,700
tonnes of weight and have a lifting
height of almost 10 metres.

412
00:30:30,360 --> 00:30:34,560
Without this machine, lifting of the
concourse platform is not possible.

413
00:30:37,740 --> 00:30:42,100
With this system in place, engineers
have created one of the world's most

414
00:30:42,100 --> 00:30:43,800
versatile stadiums.

415
00:30:46,160 --> 00:30:49,980
Able to accommodate 50 ,000 spectators
for athletics.

416
00:30:51,040 --> 00:30:55,260
And grow to feed up to 55 ,000 for
football and rugby.

417
00:30:56,100 --> 00:30:59,040
All while keeping the fans close to the
action.

418
00:30:59,420 --> 00:31:06,260
To have a retractable seat system that
can shift over 24 ,000 seats and 14 ,200

419
00:31:06,260 --> 00:31:07,360
tons of weight.

420
00:31:07,610 --> 00:31:08,610
It's definitely mind -blowing.

421
00:31:14,830 --> 00:31:19,670
But to battle Singapore's inclement
weather, they have one last challenge to

422
00:31:19,670 --> 00:31:20,670
conquer.

423
00:31:22,070 --> 00:31:26,110
Engineer Randall Lim and his team need a
structure that can adapt at a moment's

424
00:31:26,110 --> 00:31:27,110
notice.

425
00:31:29,070 --> 00:31:33,290
Having an open air stadium allows
natural light and fresh air into the

426
00:31:33,980 --> 00:31:37,040
However, there are also downsides to
having an open -air stadium.

427
00:31:37,540 --> 00:31:42,160
The stadium internals and spectators
will not be shoot from the harsh weather

428
00:31:42,160 --> 00:31:43,160
Singapore.

429
00:31:45,160 --> 00:31:50,040
A clear day in Singapore can see
temperatures of over 85 degrees when the

430
00:31:50,040 --> 00:31:52,760
stadium's occupants would benefit from
open -air seating.

431
00:31:55,340 --> 00:32:00,860
But without warning, everything can
change.

432
00:32:03,560 --> 00:32:07,380
The thing about Singapore weather is
that a typical storm will change in

433
00:32:07,380 --> 00:32:08,380
minutes.

434
00:32:08,900 --> 00:32:13,440
We do experience heavy downpour and we
get as low as 100 meter visibility.

435
00:32:15,080 --> 00:32:17,580
Immense storms can bring flash floods.

436
00:32:18,460 --> 00:32:22,100
And Singapore's annual rainfall exceeds
six feet.

437
00:32:25,260 --> 00:32:27,260
In an unpredictable climate,

438
00:32:27,960 --> 00:32:29,660
versatility is key.

439
00:32:31,280 --> 00:32:35,600
From an engineering perspective, the
solution is definitely non -negotiable.

440
00:32:35,860 --> 00:32:37,620
It has to be a marvel of structural
engineering.

441
00:32:38,460 --> 00:32:43,180
To achieve a structure that can provide
open -air views and protect from

442
00:32:43,180 --> 00:32:47,160
inclement weather, engineers must turn
to the innovators of the past.

443
00:32:55,880 --> 00:32:59,240
At one of Britain's oldest scientific
institutions,

444
00:33:00,870 --> 00:33:05,810
Historian Louise DeVoy is in search of a
groundbreaking structural innovation.

445
00:33:07,230 --> 00:33:12,610
This is the Royal Observatory at
Greenwich, the historic home of British

446
00:33:12,610 --> 00:33:15,350
astronomy, navigation and timekeeping.

447
00:33:15,670 --> 00:33:19,750
It's world famous as the basis for the
international time zone system.

448
00:33:20,130 --> 00:33:24,150
In the 1880s, the observatory procured a
new telescope.

449
00:33:24,810 --> 00:33:28,310
But this instrument's enormous size
caused a problem.

450
00:33:28,970 --> 00:33:33,490
The astronomers wanted to reuse the
existing dome that rose up directly from

451
00:33:33,490 --> 00:33:37,950
building. But the new telescope was too
long, and so a new design had to be

452
00:33:37,950 --> 00:33:38,950
found.

453
00:33:39,910 --> 00:33:44,970
To overcome this challenge, a new,
extraordinarily adaptable dome would

454
00:33:44,970 --> 00:33:45,970
be constructed.

455
00:33:46,790 --> 00:33:51,150
So how could the observatory protect its
valuable telescope from the element,

456
00:33:51,330 --> 00:33:54,490
while also providing an ideal view of
the night sky?

457
00:33:55,600 --> 00:34:00,880
We can really see the genius of
Christie's design, how it extends across

458
00:34:00,880 --> 00:34:02,280
whole extent of the dome.

459
00:34:03,140 --> 00:34:07,720
The groundbreaking engineering that made
it possible might hold the key to

460
00:34:07,720 --> 00:34:11,040
keeping Singapore National Stadium dry
in a downpour.

461
00:34:12,380 --> 00:34:13,520
There we go.

462
00:34:14,500 --> 00:34:15,500
Wow.

463
00:34:16,880 --> 00:34:22,810
When the Royal Observatory acquired a
new oversized telescope in the 1880s,

464
00:34:22,810 --> 00:34:26,870
discovered the building's original dome
wasn't large enough to accommodate the

465
00:34:26,870 --> 00:34:27,870
device.

466
00:34:29,610 --> 00:34:34,170
For astronomer royal William Christie,
the solution was crystal clear.

467
00:34:36,590 --> 00:34:40,969
He came up with a revolutionary proposal
to house the new instrument.

468
00:34:45,050 --> 00:34:48,010
This is the Great Equatorial Dome.

469
00:34:52,780 --> 00:34:55,280
Wow, certainly worth a climb up those
steps.

470
00:34:58,120 --> 00:35:04,360
Standing out on the Greenwich skyline,
this unusual onion -shaped bulb houses

471
00:35:04,360 --> 00:35:06,660
the observatory's most prized
instrument.

472
00:35:10,400 --> 00:35:14,860
Our whole view is dominated by the giant
Victorian telescope.

473
00:35:15,260 --> 00:35:16,280
Absolutely fabulous.

474
00:35:16,640 --> 00:35:20,680
But today we're more interested in the
building around it, this wonderful

475
00:35:20,680 --> 00:35:26,190
structure. Christie had to develop a
design that could expand to 36 feet

476
00:35:26,490 --> 00:35:30,550
and he came up with this very
distinctive onion -shaped profile.

477
00:35:32,350 --> 00:35:36,990
Expanding outwards from the base, the
dome is five feet wider than the tower.

478
00:35:41,250 --> 00:35:45,990
But with the telescope protected from
the weather, it still needs a way to see

479
00:35:45,990 --> 00:35:47,250
out to the night sky.

480
00:35:50,540 --> 00:35:53,360
Oh, it's quite stiff, a bit reluctant at
first.

481
00:35:54,140 --> 00:35:55,900
Christy's remarkable solution.

482
00:35:57,720 --> 00:35:58,840
There we go.

483
00:35:59,860 --> 00:36:00,860
Wow.

484
00:36:01,480 --> 00:36:05,700
An enormous adjustable shutter spanning
the entire dome.

485
00:36:09,040 --> 00:36:12,920
You can just see all the daylight
starting to flood into the dome. That's

486
00:36:12,920 --> 00:36:13,920
brilliant.

487
00:36:15,820 --> 00:36:20,560
So as we open up the shutters to their
fullest extent, we can really see the

488
00:36:20,560 --> 00:36:25,740
genius of Christie's design, how it
extends across the whole extent of the

489
00:36:26,060 --> 00:36:28,100
from horizon to horizon.

490
00:36:30,420 --> 00:36:35,640
To create this vast seven -foot -wide
partition across the roof requires some

491
00:36:35,640 --> 00:36:36,840
ingenious engineering.

492
00:36:40,760 --> 00:36:44,720
It can be operated by just one person
turning this wheel.

493
00:36:45,480 --> 00:36:50,920
So this then turns up a series of
interconnected rods up and across over

494
00:36:50,920 --> 00:36:51,920
crown section.

495
00:36:52,140 --> 00:36:57,240
You have two tail pieces supported by a
series of wheels on tracks that move

496
00:36:57,240 --> 00:36:58,440
together and move apart.

497
00:36:58,700 --> 00:37:02,980
So Christy wanted to keep this very
simple with a minimal number of moving

498
00:37:02,980 --> 00:37:03,980
that could go wrong.

499
00:37:05,140 --> 00:37:08,400
And this incredible structure has
another useful feature.

500
00:37:09,920 --> 00:37:14,900
A clever rack and pinion mechanism
rotates the dome to align with the night

501
00:37:20,080 --> 00:37:24,360
It's actually quite disorientating to
see the dome above your head rotating

502
00:37:24,360 --> 00:37:25,960
while you're still stationary yourself.

503
00:37:26,440 --> 00:37:27,440
It's truly impressive.

504
00:37:29,360 --> 00:37:33,200
Christie's innovation was ahead of the
curve and it stood the test of time.

505
00:37:34,260 --> 00:37:37,840
Still in use today, over 120 years
later.

506
00:37:40,560 --> 00:37:45,360
This telescope really paved the way for
Greenwich astronomers to observe double

507
00:37:45,360 --> 00:37:46,440
stars and the planets.

508
00:37:46,750 --> 00:37:48,250
particularly Jupiter and Mars.

509
00:37:48,550 --> 00:37:53,390
And this was all possible thanks to
Christie's innovative design for this

510
00:37:53,390 --> 00:37:55,010
and the retractable section.

511
00:38:03,490 --> 00:38:07,870
To put the finishing touches on the
record -breaking Singapore National

512
00:38:08,150 --> 00:38:12,350
engineers will need to take Christie's
idea and supersize it.

513
00:38:12,990 --> 00:38:15,970
The roof is definitely an engineering
model.

514
00:38:17,300 --> 00:38:20,600
Inspired by William Christie's 19th
century design,

515
00:38:21,380 --> 00:38:25,860
Singapore National Stadium's engineers
have built an adaptable domed roof

516
00:38:25,860 --> 00:38:32,520
on a colossal scale to beat the

517
00:38:32,520 --> 00:38:34,840
tropical rainstorms before they hit.

518
00:38:36,480 --> 00:38:41,080
The engineering solution is to have a
fully operational retractable roof that

519
00:38:41,080 --> 00:38:44,980
can open and close so that we can host
events of various nature.

520
00:38:47,280 --> 00:38:53,160
At the push of a button, these
symmetrical leaves will open or close in

521
00:38:53,160 --> 00:38:54,160
minutes.

522
00:38:57,300 --> 00:39:04,180
The National Stadium's 215 ,000 square
foot opening is an engineering

523
00:39:04,180 --> 00:39:06,780
marvel that Christie could have only
imagined.

524
00:39:11,700 --> 00:39:16,700
To shift these colossal panels on a
curved dome, takes some remarkable

525
00:39:16,700 --> 00:39:17,700
engineering.

526
00:39:18,900 --> 00:39:22,980
The retractable roof is curved to fit
the world's largest spanning dome.

527
00:39:23,240 --> 00:39:24,320
And because it's curved,

528
00:39:25,040 --> 00:39:27,020
getting them to move is a big hurdle.

529
00:39:27,400 --> 00:39:31,120
Weight must be optimized and reduced
while the retractable leaves need to be

530
00:39:31,120 --> 00:39:32,120
flexible.

531
00:39:33,180 --> 00:39:39,040
To minimize weight and maximize
flexibility, engineers designed a

532
00:39:39,040 --> 00:39:42,180
and covered it with pliable material
that can be inflated.

533
00:39:45,100 --> 00:39:50,100
The mobile roof consists mainly of ETFE
membrane, and this is lightweight and

534
00:39:50,100 --> 00:39:52,620
also allows flexibility in the roof
movement.

535
00:39:53,380 --> 00:39:57,540
Flexibility is important as we are
moving a structure of that massive size.

536
00:40:00,880 --> 00:40:06,060
Keeping components to a minimum, the
huge roof panels are shifted by just 16

537
00:40:06,060 --> 00:40:07,380
motorized winches,

538
00:40:08,360 --> 00:40:14,400
hoisting the leaves along five fixed
rails on sets of wheels known as bogies.

539
00:40:15,500 --> 00:40:20,740
There are 20 boogies carry each lift,
and total 40 boogies on the entire roof.

540
00:40:21,360 --> 00:40:24,480
Each boogie has a four -wheel contact
point to the fixed rail.

541
00:40:24,980 --> 00:40:26,780
This minimizes the contact points.

542
00:40:30,640 --> 00:40:34,740
When you see the thing from afar, the
entire mower roof looks incredible.

543
00:40:37,500 --> 00:40:40,640
The roof is definitely an engineering
marvel.

544
00:40:47,720 --> 00:40:51,900
For the team behind this daring project,
it's an immense engineering

545
00:40:51,900 --> 00:40:52,900
achievement.

546
00:40:54,380 --> 00:40:57,380
This project is so groundbreaking
because of the sheer size.

547
00:40:57,680 --> 00:41:01,240
It's the world's largest free -spanning
dome and that makes it quite incredible

548
00:41:01,240 --> 00:41:02,240
on its own.

549
00:41:06,520 --> 00:41:10,560
This must be one of the most complex
engineering projects ever undertaken.

550
00:41:12,280 --> 00:41:15,460
By building on the work of the pioneers
of the past.

551
00:41:16,919 --> 00:41:22,480
Overcoming huge challenges and pushing
the boundaries of innovation.

552
00:41:23,440 --> 00:41:28,900
It is really out of this world and with
the amount of complex challenges that we

553
00:41:28,900 --> 00:41:33,740
have faced, the Singapore National
Stadium is really a marvel of

554
00:41:35,360 --> 00:41:40,580
Engineers are succeeding in making the
impossible possible.

555
00:41:41,970 --> 00:41:44,830
I often take a step back and look at the
stadium in Wonderment.

556
00:41:45,050 --> 00:41:47,630
It's really quite an amazing
architectural achievement.

557
00:41:48,610 --> 00:41:50,370
I'm very proud to be part of this
project.

558
00:41:50,610 --> 00:41:51,610
It's just incredible.

559
00:41:51,660 --> 00:41:56,210
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