All language subtitles for When.Big.Things.Go.Wrong.S01E06.House.of.Cards.1080p.AMZN.WEB-DL.DDP5.1.H.264-BurCyg_track3_[eng]

ANNOUNCER: This program is
rated PG, and contains

ANNOUNCER: This program is
rated PG, and contains

mature subject matter.

Viewer discretion is advised.

-(SIREN WAILING)
-(HELICOPTER WHIRRING)

MAN: Oh, my God!

NARRATOR: An 18 story hotel
comes crashing to the ground.

People are panicked.
There's a lot of uncertainty.

(WOMAN SPEAKING)

MAN: Come on, get back.
Get back, sir!

That tower can
come down any time.

ROB: This structure comes
tumbling down floor by floor.

Like a house of cards.

NARRATOR: What's behind
the unexpected collapse?

This kind of thing should not
be happening today.

NARRATOR: Now...

Engineers unlock the clues
to the world's
biggest disasters.

(GLASS CRASHING)

(TRAIN CRASHES)

(PEOPLE SCREAMING)

Find out what happens
When Big Things Go Wrong.

MAN: Okay, watch it! Watch it!

These are the ultimate fears,

that keep structural engineers
awake at night.

MAN: Oh, my God!

(LOUD METALLIC CREAKING)

NARRATOR:
Saturday morning, 9:00 a.m.

The people of New Orleans
are gearing up for
a busy weekend.

Among them,
artist and producer,
Fallon O'Brien.

She's getting ready for her
regular commute.

FALLON: So, a normal day
would be to get up,

and to have a cup of coffee.

I live just around the corner
from the streetcar,

so, it would, you know,
take me just a few moments
to... to walk to the street car.

I grabbed my normal seat.

I recall juts kind of twiddling
around on my phone.

I do remember it very
specifically, because
there was a chill in the air.

NARRATOR: The streetcar
heads toward the corner of
Canal Street in North Rampart,

where a brand-new high-rise
structure's being built.

The Hard Rock Hotel.

So, the Hardrock Hotel
is going to be

quite a glamorous,
20-storey high-rise
in downtown New Orleans.

NARRATOR: Plans for
the complex include 62
condos, a 350-room hotel,

an upscale restaurant,
and over 12,000 square feet
of event space.

And it rises 190-feet high,

with a penthouse to
top it off at 205-feet.

It's set to be a spectacular
addition to New Orleans,

perfect for tourists flocking to
the biggest event of the year,

Mardi Gras.

It was gonna provide
so many jobs.

It was going to provide
a huge boom for the tourism.

NARRATOR: The hotel should've
been finished by May, 2019.

But it's now months
behind schedule,

so the pressure's on
to finish it.

Fallon's commute takes her past
the site every morning.

FALLON: I would always look up
and see the guys working.

There were hundreds
of men up there.

I would look up and kind
of in awe of...

Just like, wow, incredible
how quickly it went up.

NARRATOR: Today seems routine.

FALLON: We got to the corner
of Canal in North Rampart.

I do remember looking
up briefly.

It all happened
in a split second.

In the peripheral
of my vision,

I just see, kind of,
something falling down.

So, I look up...
I see a tangle of metal.

MAN: Oh, my God!

NARRATOR: Eighteen floors
come crashing down.

The building starts to crumble
at the very top.

And then we have this
cascade of failure,

as the floors, the concrete,
pancakes from top to bottom.

MAN: Get to the back!
Get to the back!

FALLON: People really,
at that point were
in fear for their life,

and in fear that, the building
was going to just collapse
right on the street car.

All that you're thinking is,
"Get me as far away from
this disaster as possible."

NARRATOR:
Rescue services race
to the scene.

(SIRENS WAILING)

(MAN SPEAKING)

The overwhelming majority
of buildings are built without

any kind of failure
or issues.

And this kind of thing should
not be happening today.

NARRATOR: The question...
what caused it, and how?

The mystery begins
14 years earlier,

in a disaster that hit
New Orleans hard...

Hurricane Katrina.

August, 2005,
175 mile per hour winds

batter the Gulf of Mexico
before making landfall.

Floods destroy 134,000 homes.

1,500 die.

Stormwaters overwhelm the levees
protecting New Orleans.

The entire city is devastated.

DAN: In the wake of
Hurricane Katrina,

a revitalization effort
was required

to get people to come
back into downtown,

fix the devastation
and destruction, get them
to spend money...

And the Hard Rock Hotel was
the center of it all.

NARRATOR: And as the huge new
structure takes shape,

the first clue lies in
the smallest detail.

LUKE:
In very broad terms,

if you wanna put up a building,
you start with the foundation,

make the base of the building
very stable.

And then you'll build, what is
effectively the skeleton
of the building.

Whether that's out
of structural steelwork,
or reinforced concrete.

And in case of the Hard Rock,

that was largely
structural steelwork.

NARRATOR: All this steelwork
must be connected.

Major structural components
of large buildings
are often bolted together.

It is a cheap,
but very effective way
of taking large pieces of steel,

and making a solid connection
between them.

NARRATOR: Bolts are
small components.

But they're critical

in holding the building's
frame together.

If you take an individual bolt,
it is seemingly quite small,

relative to
the structures ahold.

But the job that it does
is absolutely crucial

to the life of this building.

NARRATOR: But as investigators
sift through the wreckage

of the
Hard Rock Hotel Collapse,

they find something strange.

Many of the bolts on
the lower floors are
sheared in two.

A shear failure is where
you have forces acting
in opposite directions

on a piece of metal, say.

And the combination of those
forces exceeds the strength
of the material.

And as a result,

you get a very sudden,
or catastrophic break,
or failure.

NARRATOR: Footage reveals
the Hard Rock collapse was
indeed sudden.

So why did the bolts fail?

ROB: It could be because there
weren't enough bolts used

at those junctures
or connections.

Or it could be that those bolts
weren't big enough. That
there wasn't enough material

to have the strength needed.

Or it could be a combination
of both these things.

NARRATOR:
The question remains...

Are the shattered bolts
the result of the collapse,
or the cause of it?

In any building or machine,
if a small but crucial
component breaks,

it can trigger
a chain-reaction...

as air-race spectators in
Nevada witness.

The Reno Air Races.
Billed as the world's
fastest motor sport,

in 2011, thousands of people
are enjoying
the day's events.

In footage
shot by a spectator,

a plane can be seen
veering out of control.

(CRASHING)

(PEOPLE SHOUTING)

What went wrong?

DAN: The air races in Reno,
Nevada feature

high-performance aircraft.

They're very, very specialized
to basically

have races in the sky
for people to watch.

NARRATOR: 74 year old
James Leeward is piloting
a P-51 Mustang,

originally built in 1944.

Named The Galloping Ghost,

it's a highly-modified
former military plane.

(PLANE WHIRRING)

But mid-race,
catastrophe strikes.

(PEOPLE SCREAMING)

MAN: Oh, God!

Oh, my God!

What we see is one particular
airplane that's been so
heavily modified,

incurs mechanical failure which
causes total loss of control.

(PEOPLE SHOUTING)

So, you've got to look after
the small details.

In this case, a screw failed.

NARRATOR: The screw was holding
a vital part together...
the trim tab.

It's essential for keeping
the planes stable in flight.

Loose before takeoff,

the screw breaks once the pilot
reaches high-speed.

Once that happens,
you no longer
have an airplane,

you more have a high-speed
velocity projectile

that's gonna go wherever
gravity sends it.

This malfunction,
essentially of the flap,

caused the pilot
effectively to lose control.

And the aircraft went into
a situation where the pilot
was experiencing 17Gs.

And this can cause a blackout
quite quickly,

and the pilot then
loses control and crashes.

(PEOPLE SCREAMING)

NARRATOR: The Mustang slams into
the ground at over 400mph,

killing the pilot
and 10 bystanders.

Dozens more are injured.

When we have anything that's
complex and engineered

and made up of
a number of parts,
large and small,

often, it only takes the failure
of something quite small

to start to initiate what can
become a catastrophic event.

NARRATOR: But in New Orleans,

the fractured bolts of
the Hard Rock Hotel

are found on the lower floors.

So, something else triggered
the disaster.

But what?

(NARRATOR READING)

You've got sections of
a building that are falling
apart, that's catastrophic.

NARRATOR: Could more evidence
to the collapse lie at the very
heart of the structure?

And a tragedy at sea...

(MAN SPEAKING INDISTINCTLY)

...caused by human error.

I assumed
I was about to die.

NARRATOR:
When Big Things Go Wrong,

engineers have to search
for answers.

(MOTOR WHIRRING)

For the New Orleans
Hard Rock Hotel collapse,

should they look higher up?

2016, the framework of
the Hard Rock Hotel

is rising above
downtown New Orleans.

Modern high-rise construction
typically is composed of

a core, which goes up first,
that would be like the spine
of the building.

And then the floors branch
out from that.

NARRATOR: The core
is the main source of strength
within most high-rises.

It's made of heavy-duty
reinforced concrete.

Running from the foundation
to the very top,

it stabilizes the structure.

DAN: So, the core of
the building is

the most important
aspect, when it comes
to structural integrity.

NARRATOR: As the building goes
up, other components, like
floors and beams, are secured,

or tied-in to it.

DAN: So, when you tie
a building component

into the overall structure,
what you're doing is
you're creating

a strong and rigid
connection,

taking a separate piece
and making it
a part of a whole.

And the building at the end is
just one monolithic structure,

when in reality it's a bunch of
really small pieces that have
been tied together.

It's really important that
those elements get
tied in adequately

during the construction of
the building.

Because otherwise,

the bits of the building that
are intended to act together
to support the loads

can't do so.

NARRATOR: If the pieces
aren't tied in correctly,

it could mean trouble.

Combing through the rubble
of the collapsed
Hard Rock Hotel,

investigators find
something shocking.

The initial accident
investigation had
issued citations,

which suggest that floors
9 through 15

on the western side
of the building

were not adequately tied in
to the structural frame.

DAN: This is bad, because
the building is not one piece.

But now it's a collection of
lose pieces that doesn't have
the same strength.

This is a disaster waiting
to happen.

It's difficult to tell
whether or not the error
was in the design itself,

or whether it was in
the assembly,

or the procedure
for the assembly.

But at the end of the day,
it would lead to failure.

NARRATOR: Somewhere along
the line, has someone made
a terrible mistake?

Over 80% of all construction
accidents are down to
human error.

The same pattern's seen in other
engineering disasters.

80% of plane crashes are
caused by pilot error.

And up to 95% of all
marine accidents are also
due to human error.

Like this cruise from hell.

January, 2012.

Just off the Italian coast,

a huge 952-foot ship
sails too close to shore.

Onboard, over 3,000 passengers,

all completely unaware
of impending doom.

Suddenly, at 9:45 p.m.,
the ship hits rocks.

What causes this giant vessel
to run aground?

Costa Concordia is
an engineering monster.

The length of three
football fields,

and at 170-feet tall,
higher than Niagara Falls,

the ship weighs in at a massive
50,000 tons.

Its engineers have designed
the boat for everything
the ocean can throw at it.

ASEGUN: But it's not
designed to go near an island,

where you've got
rocky formations
and shallow water.

NARRATOR: And that's exactly
what happens.

Following departure from Rome,
the captain orders a diversion.

Instead of staying on course
through deep water,

he makes the fatal error of
sailing close to the small
island of Giglio,

reportedly to salute
a former colleague on shore.

Spotting a reef on the radar,
the captain orders the ship
to turn.

But there's a miscommunication
with the helmsman,

who steers the wrong way.

(METALLIC SCRAPING)

The Costa Concordia scrapes
along the reef,

tearing a hole
below waterline.

I was immediately thrown
back in my seat,

as if I'd been whiplashed.

And glasses were sliding off
the racks and I'm smashing
into shattered glass everywhere.

The ground underneath us
was violently shaking.

And there was this moment that
everybody was holding
their breaths,

trying out figure out what on
earth was going on.

At that point, water starts
to flood into the hole.

(INDISTINCT SHOUTING)

And that can easily start
to short-circuit,

um, to trip breakers,
and that'll cut out
your electrical systems.

NARRATOR: Pumps could be used to
get water out of the hull...

(INDISTINCT SHOUTING)

...but without power...

they're useless.

(INDISTINCT SHOUTING)

An hour after collision,
the ship's sinking fast.

It's a fight for survival for
passengers and crew.

(INDISTINCT SHOUTING)

ROSE: I looked down and
I just saw thousands of people

acting like a swarm of bees,

and just running into
one another.

There was screaming,
shouting and it was just...

so harrowing,

because we had no idea what
would happen to us.

NARRATOR: The captain
escapes on one of
the few working lifeboats,

leaving hundreds still onboard.

He gets off the ship before all
of the other passengers get off.

Which, to me,
is mind-boggling,

because you're the captain.
Isn't the captain supposed
to leave last?

NARRATOR: As dawn breaks,
the full scale of the disaster
is visible.

Thirty-two die,
157 injured.

The salvage operation
will cost a staggering
$2 billion.

The Costa Concordia tragedy
is the result of one person
making a bad decision.

But at the Hard Rock Hotel,

early reports indicate
that, shockingly,

the collapse wasn't down
to a single human error

but a whole catalogue
of them.

NARRATOR: By fall 2019,
the Hard Rock Hotel
is rising up in New Orleans.

It was definitely a sight to see
when I passed by in
the streetcar every morning,

on my way to work.

NARRATOR: But as work
begins on the 17th floor,

nobody's aware of
the weaknesses below.

And this floor features
the most ambitious part
of the design yet.

Could it also be another piece
to unravelling the puzzle?

Spread across
floors 17 and 18,

a spectacular viewing gallery.

To create it, engineers use
a cantilever.

Think of like pirates and
walk the plank, right?

The plank is sticking out
over the water.

And so that's a cantilever
that sticks out.

NARRATOR: Commonly used
in balcony construction,

a cantilever is a rigid
structure that extends
beyond the building.

It's only supported
at one end,

so it has to be strong.

A cantilever is often
referred to as an
engineer's best friend,

because it's a very, very
versatile thing that you can use
to solve lots of problems.

One of the nice things
of cantilevers,

especially in
building construction,

is that it allows you to have
unobstructed views.

LUKE: And as an
architectural feature,

you can imagine this is
something that many architects
really want to achieve.

NARRATOR: And in
the Hard Rock Hotel,

the cantilever will offer
tourists a clear view of
the entire city,

a huge selling point.

But there are a number of ways
cantilevers can go wrong,

if they're not
correctly designed.

The cantilever itself
doesn't want to be there.

It wants to fall or rotate.

NARRATOR:
Calculations must
be precise.

DAN: Not only does
the cantilever beam have
to support its own weight,

but it also has to support
the weight of other components
that are tied into it.

NARRATOR: Because nothing
else holds it up.

LUKE: Any small
increase in length has
significant consequences

for the overall strength
of the cantilever.

Because the maximum span is
intended to prevent that
cantilever from collapsing.

NARRATOR:
Making it longer also
makes it heavier.

ROB: If you don't get
the calculations of
that structure correct,

that cantilever might not be
able to take the weight

it's pushing down on it.

NARRATOR:
When that happens,
it's game over...

as shoppers
in Mexico find out.

Mexico City, July 12th, 2018.

A brand new shopping mall.

It's been open just
for four months,

but it's still partially
under construction.

The stunning facade,
held up by a cantilever,

is designed to wow shoppers.

(GLASS BREAKING)

(RUMBLING)

One of the most visually
striking aspects of
this structure is this

huge glass-fronted section that

appears to be sticking out from
the rest of the building.

And it's sticking out
because cantilevers
are holding it up.

NARRATOR: On top of it,
a roof garden is added.

But the planters in the garden
are heavy.

It's too much.

NARRATOR: A support beam fails,
and the mall is evacuated.

LUKE: Cantilever structures
are very unforgiving.

Calculating the loads
on any structure properly
is really critical,

and if you get
those loads wrong,

then there's always a chance
that you might get failure.

NARRATOR: The first sign
of trouble is when windows
start breaking.

ASEGUN: You can't really
see with the naked eye.

You don't really see
the dimensions changing,
but the glass knows

and it's feeling the stress
of the dimensions changing.

LUKE: And then, what we see
unfold is the fracture
of the panes of glass

accelerates, and then
suddenly the entire surface
of this facade drops

down onto the street below.

NARRATOR: Thankfully,
no one's hurt.

ROB: At the Hard Rock Hotel,
there's also an issue with
the cantilevers.

Investigators' report stated
that the cantilevers
on the 17th and 18th floor

exceeded the manufacturer's
guidance for maximum spans.

That means that those
cantilevers were too long
for the weight

they were being
asked to support.

NARRATOR: For now,
it stays up,
but it's compromised.

Another threat to this
vulnerable structure...

All it will take is one push
to send this house of cards
tumbling down.

And there are still
two more floors
to be added.

Coming up...
Missed warnings prove costly.

(MAN SPEAKING SPANISH)

It's very clear that
something is amiss,

and something bad
is about to happen,
very soon.

NARRATOR: As workers in
The Netherlands discover...

(WOMAN SCREAMING)

NARRATOR: When
big things go wrong,

often there
are warning signs.

But what happens
when they're missed?

Was there a moment
when the Hard Rock
collapse was avoidable?

In New Orleans, construction
teams are tackling
the hotel's top storeys.

A critical moment comes
as workers lay down
concrete floors.

ROB: When you pour concrete,
it starts off as a liquid,

and so, it needs time
to cure and harden.

DAN: It takes time
for concrete to become solid.

You have to give
it sufficient time
to set up and become strong.

NARRATOR: But on the
Hard Rock Hotel, they're rushing
to get the job completed.

While the concrete sets,

temporary supports are
put in place on the floors
below to help.

LUKE: As you're building,
you tend to want to move

more quickly in the construction
of your building,

than the concrete
can gain strength.

and the way, as a contractor,
that you deal with that
is to prop

the concrete
in the lower levels
of the floor,

until it gains enough strength
that you can take those
props away.

NARRATOR: But according
to workers on site,

temporary supports below
floor 18 are taken out
just three days after the pour.

If you remove these
supports too soon,

the concrete isn't hard
enough to support
its own weight.

DAN: And what that means is,
all that weight's gonna sag
and droop down,

and that's not something
you really, really want
in a high-rise hotel.

NARRATOR: Some on the site
noticed signs of trouble.

In footage shot by workers
just before the collapse,
the sagging is clearly visible,

and supports
are bent out of shape.

The fact that it's kinked,
and it's bent,

meant there's a lot of weight
that's trying to come
crashing down,

and there should
have been more
stuff kept underneath

to support that weight.

(MAN SPEAKING SPANISH)

Seeing that temporary
vertical support, as bent
as it is like that,

for me, would set
off loud alarms bells.

(MAN SPEAKING SPANISH)

It's very clear that
something is amiss,

and something bad
is about to happen,
very soon.

NARRATOR:
Did a missed warning

lead to tragic consequences?

It happened in Holland,

when an operation
to move a new bridge
goes horribly wrong.

(WOMAN SCREAMING)

NARRATOR: August, 2015.

Engineers prepare to replace
a section of aging bridge.

Part of the bridge deck

is being positioned
and then lowered
into place.

It's a bridge over a canal.

And it's these enormous
cranes that are going
to be doing the lifting.

NARRATOR: The cranes
weigh 400 and 700 tons each,

reaching 130 feet high.

The site's in the middle
of a busy residential area,

and contractors have planned
the operation for months.

But they've overlooked
something crucial.

The two giant cranes
sit on floating barges.

Operators raise concerns
about their stability
before the lift.

But the job
moves ahead anyway.

DAN: It's actually quite
difficult as an engineer
for me to watch.

You look at it and you see
this doesn't look like
a good scenario.

As soon as they lift,
it's already kind of leaning

and then, as they slowly move,
it's watching this disaster
unfold in slow motion.

NARRATOR: The bridge
section starts to sway.

And the barge
with the smaller crane tilts.

These cranes are now
reaching a point
of no return.

And at some point, you can see
people realize, essentially,
that all is lost,

and they're now just trying
to get out of the way
of the impending collapse.

WOMAN: Oh!

NARRATOR: The crane breaks...

(WOMAN SCREAMING)

...and falls sideways,

setting off a domino effect.

(WOMAN SCREAMING)

NARRATOR: Miraculously,
nobody dies.

(NARRATOR READING)

In New Orleans,
what pushes the Hard Rock
over the edge?

LUKE: A structure
in this situation,

is potentially just teetering
on the brink of collapse.

NARRATOR: Dawn.
New Orleans.

As the sun rises
over the city,

the Hard Rock Hotel
approaches breaking point.

It's the weekend.

Construction teams race
against the clock to finish
ahead of Mardi Gras.

A large number of construction
workers were working over
various levels of the building,

doing various activities,
right away from the top
of the structure,

all the way down,
to the base.

NARRATOR: On the 18th floor,
the crew adds a new piece
of equipment...

a scissor lift.

This is a very heavy
pieces of machinery.

NARRATOR: It weighs
3,000 pounds,

and it's placed
on the recently-poured
concrete slabs.

My expectation,
as a structural engineer,

would be that anyone
who has put that
scissor lift there

has thought very carefully about
whether the floor slab is gonna
be able to support that load

in an effective way.

NARRATOR: In the streets
surrounding the hotel,

the weekend crowds
are already growing.

FALLON: Even as early
as 9:00, it's a busy,
busy place.

So there was cars
and streetcars passing by,
and people in the sidewalks.

I made my way
to the streetcar,

and everyone had a really
nice little, sort of sprite
to their step.

And the streetcar
pulled up.

I grabbed my normal seat,
everyone grabs their seats,
and...

and we make way
down Canal Street
on the streetcar.

NARRATOR: Fallon's route
will take her right past
the Hard Rock Hotel.

She's unknowingly
heading towards danger.

150 feet above her bus,

the Hard Rock is minutes
from collapse.

Workers move the scissor lift
to the western side
of the 18th floor.

DAN: That scissor lift
represented a point load
on one of the upper floors,

in a position somewhere
that may or may not be

mechanically as strong
as it should be.

NARRATOR: On the floor
directly below,

some of the temporary supports
have been removed,

and the concrete
isn't fully set.

If you have a floor slab
that hasn't got the strength
that it needs,

and you put
a significant concentrated
load on that floor slab,

that could lead to failure
by some or other
mechanism.

It's big, it's heavy,
and it could push this
over the edge.

NARRATOR: Fallon's streetcar
reaches the Hard Rock Hotel.

Like the workers
on the building,

she's unaware
a chain reaction
has already begun.

It's now unstoppable.

When you move
the support, then the concrete
might start to bend or crack.

There absolutely
shouldn't be deforming
in a building such as this.

FALLON: We got to the corner
of Canal in North Rampart.

I do remember
looking up briefly.

It all happened
in a split second.

I just recall looking
back down at my phone,
and then hearing

what sounded just like
things beginning to fall.
Large, heavy concrete

and faint screams
in the distance.

MAN: Oh, my God!

All of a sudden,
there's a huge dust cloud,
people are panicked.

(LOUD RUMBLING)

DAN: There's a lot
of uncertainty.

MAN: Get to the back!
Get to the back!

NARRATOR: Bystanders
are in total shock.

MAN:
Everybody, get back,
get back!

FALLON: We got out
of the streetcar
pretty quickly.

You couldn't see
a 100 to 200 feet
in front of you.

Everything was just grey
and very apocalyptic.

And people were
covering their mouth,
and screaming, and ducking,

and just running
as fast as they can,
away from the site.

(SIRENS WAILING)

NARRATOR: Bystanders
are in total shock.
The nightmare's only beginning.

LUKE: A structure
in this situation

is potentially just teetering
on the brink of some
further collapse.

MAN 1: Come on,
get back, get back.

MAN 2: That tower could
come down any time.

Any one of those
could go down.

(MAN SPEAKING)

(INDISTINCT SHOUTING)

There were these huge,
like, cranes, um,
that were dangling

so precariously
over the building.

Nothing looked very stable
at that point.

ROB: These are huge,
great, big imposing machines.

They're kind of
just left hanging.

They can actually come
crashing down into the streets
of downtown New Orleans.

It was a dangerous,
very dangerous situation.

NARRATOR:
Rescue is slow
and painstaking.

Eventually dozens
of trapped victims
are recovered.

But three workers die.

FALLON: That day was...

pretty horrifying,
um, on so many levels.

It was really sad and tragic,
'cause you could hear, they were
crying and screaming,

and people were, you know,
in tears, a mess, um,

having been
bear witness to that.

NARRATOR: And now,
New Orleans wants answers.

(MAN SCREAMING)

NARRATOR: When
Big Things Go Wrong...

The causes
can be obvious.

(MAN SPEAKING)

But for the busy city
of New Orleans, the disaster
comes out of nowhere.

LUKE: In a modern
American city,

For a major hotel
like this to literally
fall out of the sky,

shows there is something
very wrong here.

NARRATOR: Seen through the eyes
of engineers, the clues
have been building.

The lower floors...

ROB: With this hotel,

the bolts actually sheared,
they snapped in two.

NARRATOR:
Floors nine to fifteen...

When you have
portions of the floors
that aren't tied in,

these pieces of the building
are almost floating in space.

NARRATOR: The cantilever
on floors 16 and 17...

If you get those loads wrong,
then there's always a chance
that you might get failure.

NARRATOR: And too much
weight on the top floor...

If you remove these supports
too soon, the concrete
isn't hard enough

to support its own weight.

NARRATOR: Until finally,
collapse is inevitable.

DAN: The buckling of
the column in that footage
taken right before the accident,

it hints at what
the problems are.

NARRATOR: When some
of the supports are removed
on floors 16 and 17,

the remaining ones
become overloaded.

They buckle under the weight
of recently-poured concrete,

which hasn't had time to set.

If you take the supports
away from concrete that's
been cast fairly recently,

then the concrete
isn't strong enough
to support its own weight,

and that could lead
to a collapse.

NARRATOR: When
more weight's added...

DAN: That scissor lift
represented, kind of,
like a point load

on one of the upper floors.

NARRATOR:
There's no saving it.

The building starts
to crumble at the very top.

ASEGUN: All it takes
is one section of the structure
to give way,

and it slams down on top of
another structure which was not
designed to hold that weight.

NARRATOR: Unable to take
any more, the supports holding
up the 18th floor give way...

crashing into
the viewing gallery.

And now, it's kind
of this domino effect
that accelerates

and components
just keep failing,
one after another,

and the weight is transmitted
to the remining members
that are still standing.

NARRATOR: Weaknesses
further down only make
things worse.

The lower floors, not properly
tied in, can't support
the falling building.

DAN: You see the top
floors begin to fall down
on the lower floors,

causing this cascading
failure of crumbling floors,

breaking material, bent steel,
and then the entire front
of the building rips away.

NARRATOR: The sheared bolts
on the lower floors
are the result of the collapse.

ASEGUN: Because
they become overloaded

when all other weight of the
building is transmitted, as the
whole thing just falls apart.

NARRATOR: Modern buildings
simply shouldn't pancake down
in the way the Hard Rock does.

But it seems this structure
is more house of cards
than strong concrete and steel.

And anyone who's
ever actually built
a literal house of cards

will know that
if the cards at the top
of the stack fall down,

the rest of the cards
are likely to follow.

NARRATOR: The consequences
of this failure are tragic.

Three workers die,

30 are injured.

The site is so unstable,

it takes emergency workers
ten months
to retrieve one of the bodies.

There's still anger
and hostility after everything
that's gone on, because

the building stood for
almost a year.

So, you know,
it acted as this tomb.

It was this gloomy, gloomy
stamp on our city.

NARRATOR: Finally,
17 months after the collapse...

(EXPLOSION)

...demolition begins.

Two building safety inspectors
were suspended without pay

for allegedly
falsifying reports.

But with investigations
still ongoing, it's unclear
who is ultimately at fault.

It sort of
tore the city apart
to some degree.

You know, there was
lot of pointing fingers,
and who was to blame.

NARRATOR: What's certain
is a number of mistakes
contributed to this disaster.

And since over 1,000 workers
have died on US construction
sites in recent years,

it's crucial
to learn from them.

As buildings soar higher,
the risks increase.

In reality, nothing
always goes right.

Sometimes,
mistakes are made.

It's the job of engineers,
architects, and designers
in construction projects

to make sure that
if mistakes are made,
they don't catastrophically

cause the entire
project to fail.

The upshot of all this is,
we should learn from this.

We should look back and examine
what went wrong and make sure
those mistake aren't made again.

MAN: Oh, my God!