Original subtitles

[Narrator] Construction. Heavy machinery.

Tight schedules. Millions at stake.

What could go wrong?

Everything.

Whether it's faulty equipment, poor design,

human error or just bad luck, these are...

Construction Fails.

In this episode...

Staircases...

we use them every day without thinking...

...and we only notice them when they fail.

The crane is an extremely useful

means of lifting heavy things...

...but when the thing is too heavy...

...heads can roll.

Construction vehicles are great for carrying stuff...

...but sometimes we ask them to carry too much.

Giant smokestacks push our junk into the sky...

...but what happens when they become junk themselves?

Stairs.

They are everywhere.

We go up...

...and down them everyday.

Without thinking about how they're constructed,

until they fail...

We look back and we blame the stairs for tripping us up...

For breaking the rhythm of our day.

Of course it's our fault for not lifting our feet.

Or is it?

On this staircase at a subway exit in New York City,

everyone was tripping.

Were they clumsy?

Or did the stairs fail?

The answer lies in the evolution of steps into stairs.

It's a 10,000 year construction journey.

Born of necessity...

as a means of keeping out of harm's way.

A journey of trial and error...

...and the occasional broken neck.

Before stairs there were ladders,

also known as trees.

Stairs are a dramatic improvement.

Stairs allow us to overcome gravity

while maintaining the use of our hands...

Over the centuries, builders have refined the step

for maximum effectiveness and usability.

Stairs evolved in pace with the buildings around them.

Constant practice led to refinements

in construction technique.

The step is two parts: The horizontal tread

and the vertical riser.

Both working in concert to keep us moving

from high to low and vice versa...

...without needing to think.

Each part is critical to the success of the staircase...

and our safe arrival at the bottom or top.

The tread -- or the run -- is the part of the stairway

that a person steps on.

Its depth is measured from the outer edge of the step

to the riser.

The building code recommends a minimum depth

of 25.4 centimetres.

The rise -- or height -- of a step is measured

from the top of one tread to the top of the next tread.

The building code recommends a maximum rise

of 19.7 centimetres.

So after all these years, why do stairs still trip us up?

It's partly because climbing stairs

doesn't come naturally to us.

Human beings were designed to move over level ground.

Stairs demand a different type of leg and foot movement,

a different gait.

And the effort uses up a lot of energy.

Both are factors in falls,

fails

and missteps.

But that wasn't the problem in New York.

Everyone was tripping at the same spot.

Was it an optical illusion?

That's no joke:

Bottom of flight illusion is the technical term

for a trick of the mind.

It's the moment when you've reached the bottom of the stairs

in your head...

while your feet are one or two treads

above the landing.

Your brain thinks you're at the bottom...

and then you land on your bottom.

Bottom of flight illusion is often blamed

on construction fails like poor lighting...

...or a truncated handrail that stops before

the bottom of the staircase.

But in this instance the lighting was good,

the handrails were fine and people tripping

were only tripping on the way up.

The video of New Yorkers stumbling

in the Brooklyn subway went viral...

And it reached the people

at the Metropolitan Transit Authority,

which operates transit in the Big Apple.

Within hours, a repair crew was on the scene.

The workers said it was the fastest response

to a complaint in the history of the city.

It took some time to figure out the problem.

The culprit was a riser out of step with the others.

The sixth step from the top was 20.3 centimetres high.

That one step broke the building code's

recommended height of 19.7 centimetres.

But the real problem was that all the other steps

were between two to three centimetres shorter.

The commuters didn't have a chance.

In the end, the entire staircase was rebuilt.

Now the commuters at 36th Street in Brooklyn

can take these stairs for granted too.

The crane is a simple and incredibly powerful machine.

Soaring above the skyline cranes can lift construction materials

hundreds of metres in the air to build towers.

Some cranes are towers themselves.

They all operate on the simple principles of levers,

pulleys and balance.

The lever or mast is fixed to a sturdy base

and balanced by a hefty counterweight.

The mast tilts on a fulcrum to lift its load.

A crane can manage everything from an entire floor

of a building to the deck of a bridge.

When the conditions are just right,

a crane can lift and lower its load into place

with perfect precision.

But if just one element is out of joint,

the sky can fall.

So why do cranes fail?

This statue of a former head of state

was slated for removal and relocation.

And while the crane was mounted securely on the truck bed,

the noose around the leader's neck was not.

As the crane swung the statue off its pedestal,

the crane operator lost his head.

Cranes are a danger to anything below.

One moment you're driving along the road,

minding your own business, and the next moment,

you're in a deadly game of dodge 'em.

There's no defense from the guillotine power

of gravity plus crane.

Even when a car isn't moving, the crane can be cruel.

This SUV had already taken a beating

before the crane stepped in.

Talk about hurting someone when they're down.

Citizens of a small coastal village in Canada

congregated to watch a crane remove the steeple

from the top of their local church.

It was supposed to lift it off the 150-year old building

and lower it gently to the street.

Lift capacity follows a basic law of physics.

The further you extend the mast from the base

the more stress you put on it.

At 90 degrees, it's at maximum stress.

Just like your arm holding a dumb-bell.

But the crane operator must've skipped that physics class.

Because as the mast extends beyond the allowable angle,

the weight of the spire becomes too much.

With a metallic screech,

the mast snaps and drops the steeple,

which plummets to the ground with an unholy crash.

This lucky Buddha statue had a very unlucky day.

When the crane lifted the giant statue off the ground

the cables gave way.

Buddha fell flat on the sidewalk...

talk about a loss of face.

They're going to need a bucket of super glue

to restore this deity.

When a dead sperm whale washed ashore in Uruguay

a crane was enlisted to carry it off.

But the straps snapped under the 22 tonnes

of bloated carcass.

Slippery, even when dry.

The very thing that makes cranes so powerful

is what makes them so dangerous.

When very heavy things are suspended very high in the air

you want to be somewhere else if something -

or someone fails.

Sometimes what goes up...

...comes down hard.

When it comes to construction, size matters.

So what if your vehicle isn't big enough

to get your supplies from here to there.

With a little ingenuity

and a complete disregard for personal safety,

you can really pile it on.

Trucks with a load overhanging the vehicle by 1.5 metres

require a red flag.

This guy's going to need way more flags.

Because otherwise who's going to notice him?

One sudden move and those poles could fly off

and poke out an eye.

Here's a conga line of bad ideas.

Ten trailers piggy-backing one truck.

When the cops finally caught up with this chain of fools

they demanded the driver produce his license

and registration.

And registration. And registration.

And registration.

And registration.

It's hard to imagine you can lug more Styrofoam boxes than this.

Now you don't have to.

This pint-size scooter comes with a king-size bed.

This one comes with a king-size blind spot.

Maybe consider driving on the right side of the road?

This motorbike hits a red light and those drums

are going to make more racket than a marching band.

So this is how online retailers get your stuff to you so fast.

They're using self-driving scooters now.

Uh, your birds seem to have flown the coop...

Oh, no, wait. There they are.

This bike comes with a spare tire.

This guy's bananas.

Looks like this bottom-heavy trike is trying to ship by air.

This transport vehicle is called a "tipper truck".

Obviously.

If you feed the back with a hefty cargo of treats,

this truck will sit up and beg.

But too many treats can lead to excess weight.

Sometimes hauling an oversized load

can really take its toll.

Why make three trips when you can get it all done in one?

And if you have to improvise, it's worth it.

Because when it comes to carrying that weight,

"more... is more."

Smokestacks.

Belching smoke, steam and all sorts of fumes.

They're the business end of the fossil fuel industry.

Smokestacks are high...

...but not for reasons you might think.

The original design dates back to the Industrial Revolution.

The idea is not to push the smoke high into the air,

it's to draw oxygen into the combustion.

A tall column of warmer air

increases the draft into the furnace.

This is known as 'natural draft'

or the 'stack effect'.

Which is why we call them smokestacks.

By the 20th century, electric fans

solved the draft issues.

By then city dwellers were demanding smokestacks

that did not pump pollution so close to home.

So smokestacks started to get taller

to push the pollutants higher into the atmosphere.

Today, some smokestacks are over 400 meters high.

But when a really tall smokestack reaches the end

of its working life,

the best way to retire is to lay down.

But some smokestacks simply refuse to lay down,

in any direction.

And that's what happened in New Brunswick, Canada.

This decommissioned power plant was slated for demolition.

The power authority even raffled off the opportunity

to push the button on the blaster.

But the prize winner was sorely disappointed.

As were the hundreds who gathered to watch the spectacle.

The entire power plant,

the two smokestacks and the boiler buildings,

were supposed to disappear in a giant puff of smoke.

But when the button was pressed, only one building collapsed...

Partially.

And a lone smokestack fell a mere five metres.

So, what went wrong?

This decommissioned power plant in Australia

provides a textbook example of what should have happened.

This is how to blow up not one but two smokestacks.

The two towers lower like guns on a battleship.

As with any controlled demolition,

the key elements are planning and explosives.

But bringing down a smokestack is not like

bringing down a building.

When knocking down a smokestack,

demolition experts follow a standard procedure.

They create what is called a 'blasting cut'

near the bottom of the stack.

First, the team cuts large windows in the concrete

of the smokestack.

These 'directional windows' direct the energy of the blast

in the direction of the desired collapse.

The dynamite is packed on the inside wall

between the windows.

The explosion has nowhere else to go.

In a controlled demolition of a building,

the structure is blown inwards...

So the debris drops into the building's footprint...

This decommissioned power plant in Florida

offered something for everyone.

First, the main boiler structures were dropped

into their own footprint.

Then it was time to topple the towers.

For obvious reasons, larger smokestacks

are built in industrial zones

with lots of surrounding open ground,

so there's lots of room to drop sideways.

This is called 'directional collapse'.

And that's what they wanted in New Brunswick,

but there was no collapse in any direction.

Some might wonder if there was enough

dynamite for the job...

Or whether the dynamite was misplaced.

According to news reports, the demolition company said

"the structure didn't react as anticipated."

The red-faced demolition team had to wait two weeks

before they could try again.

This time they did it in two parts.

The first blast brought down the boiler unit.

And then one smokestack.

A few hours later, they completed the job.

This time there was enough boom for everyone.

The ladder is a simple and elegant invention

that's been around for more than 10,000 years.

Which means for at least that long,

people have been falling off them.

The humble ladder is a simple machine,

made out of steel or wood, even rope.

Some people can even build one themselves.

But some can't.

Remember, it's important to plant the ladder

firmly on a non-slip surface.

Because...

this.

And everybody knows ice is not considered a non-slip surface.

Almost everybody.

This ladder is stable.

Bob the builder not so much.

This construction site gag brought the house down.

Looks like this handyman is quitting his day job

to join the circus.

This social climber is either planning a heist

or trapped in the underground garage.

Either way, that's definitely going to attract attention.

It's lights out for this odd couple's relationship.

Here's a tip, setting up a ladder on the stairs

is a step in the wrong direction.

In this case... Down.

Luckily this gentleman's fall was broken by his...

oh dear.

This guy just found out his girlfriend's cat

is stuck up a tree.

They say it's bad luck to sit under a ladder.

So could you just move slightly to your...

Never mind.

Anybody want to play a game?

The idea is to come down off the ladder

before the ladder comes down on you.

You lose.

This is called a step ladder.

Read the manual.

Fool me once, shame on you.

Fool me twice...

You better take that ladder with you

or it's going to end badly.

Every year in the United States,

500,000 people are treated for ladder-related.

So the next time you grab a ladder

be sure to come down the way you went up.

♪ ♪