00:00:00
hello everybody welcome back to another
00:00:01
episode of mega projects this one oh my
00:00:04
well how do you pronounce an o with a
00:00:06
slash through it
00:00:07
help me out pronunciation wizard
00:00:10
harrison erisen
00:00:12
arisen i'm sorry
00:00:15
trying my best
00:00:16
or some bridge that's what this video is
00:00:18
about let's jump in
00:00:19
[Music]
00:00:28
this mega project may have the word
00:00:30
bridge in its name but it's really much
00:00:32
more than that tirison bridge which
00:00:34
connects denmark and sweden is now one
00:00:35
of those iconic structures known around
00:00:37
the world that has begun to define the
00:00:39
early 21st century hotbridge part island
00:00:41
part tunnel this is a true marvel of
00:00:45
modern engineering the danish call it
00:00:46
orison bruin the swedish call it orison
00:00:52
why languages why but let's just call it
00:00:54
the bridge alright now if you happen to
00:00:56
watch the worldly popular detective
00:00:57
drama with the same name about a murder
00:00:59
committed halfway across it you probably
00:01:01
know all about it i haven't seen that
00:01:02
show if i did i probably know how to
00:01:03
pronounce it wouldn't i
00:01:05
let's see if it's on netflix tonight the
00:01:07
orison bridge is the longest combined
00:01:09
road and rail bridge in europe and it
00:01:11
stretches nearly 16 kilometers that's 10
00:01:13
miles connecting the greater copenhagen
00:01:16
and malmo areas but as i said this is
00:01:19
much more than just a bridge if you're
00:01:21
coming across from sweden about halfway
00:01:22
across the orison sound the stretch of
00:01:24
water between the two countries the
00:01:26
bridge dives down into an artificial
00:01:28
island and disappears into a tunnel only
00:01:31
to reappear four kilometers 2.5 miles
00:01:34
later next to copenhagen airport so why
00:01:37
why such an intricate combination of
00:01:39
bridge ireland and tunnel well keep
00:01:41
watching and you're gonna find out
00:01:43
that'll be good for my watch time
00:01:44
[Music]
00:01:49
let's just say from the outset here
00:01:51
there are few pieces of engineering
00:01:53
around the world quite as spectacular as
00:01:55
the earthen bridge it's not the tallest
00:01:57
it's not the longest and it's probably
00:01:58
not even the most visually striking but
00:02:01
traveling across it you can't help
00:02:02
getting a sense that you're passing
00:02:04
through the pinnacle of modern
00:02:06
engineering building something like this
00:02:08
would have been unimaginable 50 years
00:02:10
ago but the idea of connecting denmark
00:02:12
and sweden goes back to the second half
00:02:14
of the 19th century the giant leap
00:02:16
forward taken during the industrial
00:02:17
revolution showed that in theory a
00:02:19
bridge connecting the two countries
00:02:20
across the oregon sound was at least
00:02:23
possible though cost and obscure
00:02:25
economic benefits were huge stumbling
00:02:27
blocks instead the two countries focused
00:02:29
their efforts on the tried and tested
00:02:32
sea transportation as it remained
00:02:34
significantly easier and cheaper in 1865
00:02:37
swedish engineer clase adelskold
00:02:40
submitted a proposal to the king of
00:02:42
sweden carl xv carl look at you you
00:02:45
legend with an easy-to-pronounce name to
00:02:47
build a railway tunnel beneath the
00:02:48
orison sound but this was turned down in
00:02:50
1889 an underwater railroad tunnel
00:02:53
between elsinore and helsingborg was
00:02:56
also rejected both again due to
00:02:58
exorbitant costs and kind of just lack
00:03:01
of need for it this began to change at
00:03:03
the dawn of the 20th century the new
00:03:04
form of transportation arrived and would
00:03:06
go on to revolutionize how we travel the
00:03:08
automobile gave people a level of
00:03:10
freedom that had been unheard of until
00:03:11
that point and suddenly the idea of a
00:03:13
bridge across the sound became a whole
00:03:15
lot more enticing during the 1930s there
00:03:18
were serious discussions surrounding the
00:03:20
project involving some of the leading
00:03:22
nordic engineers at the time but as you
00:03:25
probably know the 1930s in europe
00:03:27
started to go downhill fairly rapidly
00:03:28
and both governments made the quite
00:03:30
sensible decision that with the build-up
00:03:32
of arms throughout europe it probably
00:03:34
wasn't the best time to begin a giant
00:03:37
construction project discussions picked
00:03:39
up again in the 1950s and rumbled on for
00:03:41
the next few decades but vehement
00:03:44
opposition from farmers
00:03:45
environmentalists and eventually both
00:03:47
governments appeared to torpedo the
00:03:49
proposal once and for all by the early
00:03:51
1990s things had changed the collapse of
00:03:53
the ussr offered a glimpse of a tighter
00:03:56
global connectivity and there was also
00:03:58
the fact that both denmark and sweden
00:04:00
were in the midst of serious financial
00:04:01
crises so what better way to boost the
00:04:04
economy and encourage trade than
00:04:06
building one of the world's greatest
00:04:07
engineering projects right on your
00:04:09
doorstep in 1991 both the danish and
00:04:11
swedish governments issued a bilateral
00:04:13
agreement on the building of the orrison
00:04:15
bridge and 126 years after the first
00:04:17
proposal was submitted the project
00:04:20
finally got its green light
00:04:26
but there was of course a long way still
00:04:28
to go several factors meant that simply
00:04:30
building a massive suspension bridge
00:04:32
across the orison sound was out of the
00:04:33
question its proximity to copenhagen
00:04:35
airport meant that tall man-made objects
00:04:37
were seen as far too risky after all the
00:04:40
last thing you want after building such
00:04:41
a superb structure is for a plane to
00:04:44
smash into it in thick fog but the
00:04:46
bridge also couldn't be too low as the
00:04:47
sound sees heavy boat traffic the second
00:04:50
issue was how to combine a road and rail
00:04:52
connection your traditional cable
00:04:54
suspension bridge often looks wonderful
00:04:56
but it's normally far too shaky for
00:04:58
trains that rather annoyingly prefer a
00:05:01
nice flat vibration-free surface stupid
00:05:04
annoying trains whatever design would be
00:05:06
used it would have to stretch the
00:05:08
boundaries of modern engineering a
00:05:10
design contest was initiated both as a
00:05:13
way of garnering a wide selection of
00:05:14
ideas but also to gain plenty of
00:05:16
publicity the final design was composed
00:05:18
of work drawn from jorg and nielsen and
00:05:21
klaus falbel hansen and ober arab and
00:05:24
partners and niels gimsing and george
00:05:27
rodner and it was ambitious to say the
00:05:30
least the design called for a bridge
00:05:32
measuring eight kilometers five miles
00:05:33
that would travel from the swedish coast
00:05:35
at the small island roughly in the
00:05:37
middle of the sound oh we should add
00:05:39
here that there weren't actually any
00:05:41
suitable islands in that particular
00:05:42
stretch of water so an artificial island
00:05:44
would have to be created on this newly
00:05:46
formed island the road and rail line
00:05:49
would then disappear into a black hole
00:05:51
and travel four kilometers that's two
00:05:52
and a half miles through the dragdon
00:05:54
tunnel before re-emerging on the danish
00:05:56
side of the sound
00:05:58
[Music]
00:06:03
the most visually impressive section of
00:06:04
the orison bridge must be the bridge
00:06:06
itself to be fair that's probably
00:06:08
because you can't actually see the rest
00:06:10
of it as i mentioned earlier in the
00:06:12
video a transitional suspension bridge
00:06:13
would have been unsuitable for train
00:06:15
travel so designers went with a
00:06:17
cable-stayed design which can transfer
00:06:19
the massive weight through multiple
00:06:20
cables back to the main towers the
00:06:23
bridge consists of four main support
00:06:25
towers each 204 meters that's 669 feet
00:06:28
high equivalent to a 60 story building
00:06:31
and has 160 separate cables its towers
00:06:34
are completely unconnected from one
00:06:36
another a design feature chosen so that
00:06:38
in the worst case scenario that a plane
00:06:40
was to hit one of them the bridge would
00:06:41
in theory remain standing a four-lane
00:06:43
road passes along a horizontal girder
00:06:45
that runs the length of the bridge with
00:06:47
two railway tracks running beneath the
00:06:49
road the height of the bridge leaves 57
00:06:51
meters that's 187 feet of headroom for
00:06:54
shipping to pass under the main span the
00:06:56
four support towers are connected to
00:06:58
giant foundations that were first
00:06:59
constructed on land each foundation
00:07:01
measured 1 500 square meters weighed 18
00:07:04
000 tons and reached 22 meters in height
00:07:06
and they were all lowered into trenches
00:07:08
dug into the sound 17 meters deep once
00:07:11
the foundations were in place
00:07:12
construction could begin to slowly raise
00:07:14
each of the four towers when they
00:07:16
reached 44 meters the cross beam was
00:07:18
added and at 80 meters a steel box for
00:07:20
the cables was also installed with
00:07:22
additional boxes every 12 meters the
00:07:24
horizontal girders where the road and
00:07:26
railway lines run were then added with
00:07:28
each section measuring 140 meters in
00:07:30
length 23 meters wide and weighing 5.5
00:07:33
million tons each again these were first
00:07:35
constructed on land then installed
00:07:37
during a painstakingly slow process
00:07:39
where they were gradually winched up
00:07:40
from a truly heavy weightlifting barge
00:07:43
in total the bridge weighs 82 000 tons
00:07:45
which for a comparison is about eight
00:07:47
eiffel towers
00:07:53
in august 1995 dredging work began in
00:07:56
the orrison sound that would eventually
00:07:58
create the artificial island of perbahol
00:08:00
the island was formed almost exclusively
00:08:02
of dredged seafloor material which is
00:08:05
great to simply want to build a landmass
00:08:06
that could accommodate people in small
00:08:08
structures but made drilling a tunnel
00:08:10
through it absolutely impossible and
00:08:12
we'll get into a bit more detail on that
00:08:14
in the next section now the first step
00:08:16
was to build a perimeter that the island
00:08:17
would eventually fill and to do this 1.8
00:08:19
million tons of large quarried stones
00:08:21
were brought in from sweden this
00:08:23
perimeter was carefully set using gps
00:08:25
and measured 12 kilometers in length
00:08:27
when completed then came the mammoth job
00:08:30
of actually dredging enough seafloor
00:08:31
material to create the island this was
00:08:34
done with some absolutely colossal
00:08:36
pieces of machinery most notably the
00:08:38
largest dip dredger in the world the
00:08:40
chicago with a shovel capable of digging
00:08:42
up 22 cubic meters of seabed in a single
00:08:46
scoop that's about 776 cubic feet by the
00:08:49
way the material was then transferred
00:08:50
onto floating barges and moved to the
00:08:52
island area where smaller diggers piled
00:08:54
the seabed up in order to create the
00:08:57
island pebble home is four kilometers
00:08:59
long with an average width of 500 meters
00:09:01
and a height of 20 meters and this being
00:09:03
built by the rather thoughtful
00:09:05
scandinavians the entire island has been
00:09:07
designated as a nature reserve seen very
00:09:09
much as a natural experiment the island
00:09:11
has thrived since its creation and is
00:09:12
now home to over 500 separate plant
00:09:14
species to add a little spice or sting
00:09:17
rather
00:09:19
in 2005 environmental researchers
00:09:21
discovered the venomous hobo spider on
00:09:22
the island a creature only found in
00:09:24
certain spots of denmark it's believed
00:09:26
to have traveled there by train which
00:09:27
seems rather appropriate considering its
00:09:30
name
00:09:30
hobo
00:09:33
[Music]
00:09:36
as i just mentioned the fact that pear
00:09:38
beholm was built entirely with seafloor
00:09:41
material meant that engineers needed to
00:09:42
find another way of inserting four
00:09:44
kilometers worth of tunnel under the
00:09:45
orison sound the word inserting might
00:09:47
sound a little strange when talking
00:09:49
about a tunnel but essentially that's
00:09:51
exactly what happened with tunneling out
00:09:53
of the question the drogdon tunnel was
00:09:55
actually formed of multiple concrete
00:09:57
tunnel segments built at a danish
00:09:58
facility that were then placed inside a
00:10:00
tunnel trench that had been dredged from
00:10:02
the danish coast to the island of pebble
00:10:04
holm in the middle of the sound this
00:10:06
trench was 11 meters deep 46 meters wide
00:10:09
and had a total of 2 million cubic
00:10:10
meters of seabed excavated from it to
00:10:13
kill two birds with one stone or several
00:10:15
billion stones if you really want to be
00:10:17
finicky the material removed from the
00:10:19
trench also made up part of paper home
00:10:21
and was transferred there via
00:10:22
purpose-built pipelines the 20 segments
00:10:25
were outrageously big each measuring 175
00:10:27
meters long 38 meters wide and 8.5
00:10:29
meters high they included five tunnel
00:10:31
sections two for cars two for rail
00:10:33
transportation and one for emergency use
00:10:35
each piece weighed a massive 55 000 tons
00:10:38
that's four times the weight of the
00:10:39
brooklyn bridge in case you're
00:10:40
interested and also included forty
00:10:42
thousand tons of reinforced steel bars
00:10:44
which acted as the frame which was then
00:10:46
filled with concrete all 20 segments
00:10:48
used a combined 7.5 trillion liters
00:10:52
worth of concrete as 1.9 trillion
00:10:54
gallons which is enough to build a
00:10:56
pavement round the entire earth
00:10:59
twice the segments were all sealed shut
00:11:01
which allowed them to be floated out
00:11:03
into the sounds i know this sounds
00:11:04
unbelievable but it did really happen
00:11:07
they were then lowered into the trench
00:11:08
with the entire stretch then backfilled
00:11:10
to create a tunnel that hadn't actually
00:11:12
been tunneled if i'm making any sense
00:11:15
here i think i am and perhaps
00:11:16
unsurprisingly considering the
00:11:17
complexities it was while building the
00:11:19
tunnel that the project faced its most
00:11:21
dramatic moments an eagle-eyed worker on
00:11:23
one of the barges suddenly noticed
00:11:24
something metallic in a pile of rock
00:11:26
that had been brought up from the sea
00:11:27
floor taking a closer look he was
00:11:29
horrified by what he saw the chicago had
00:11:31
dredged up an unexploded bomb from world
00:11:33
war ii and had dumped it unknowingly on
00:11:35
the barge miraculously it hadn't gone
00:11:38
off and the site was quickly evacuated
00:11:39
the danish navy was called in to defuse
00:11:41
the bomb and
00:11:43
everyone breathed a sigh of relief but
00:11:45
things weren't over another bomb was
00:11:46
soon discovered and the decision was
00:11:48
taken that no area could be dredged
00:11:50
until it had been swept for bombs first
00:11:51
astonishingly a total of 16 allied bombs
00:11:54
from the second world war were
00:11:56
discovered during the construction of
00:11:57
orison bridge but fortunately all of
00:12:00
them were defused safely
00:12:04
[Music]
00:12:07
the orison bridge took nine years to
00:12:09
build and despite finding far too many
00:12:10
unexploded bombs for comfort it was
00:12:12
finished three months ahead of schedule
00:12:14
rare on megaprojects it officially
00:12:16
opened to the public during several open
00:12:18
days between the 9th and 12th of june in
00:12:20
the year 2000 and was inaugurated with
00:12:22
plenty of gusto on the 1st of july of
00:12:25
that same year it cost a total of 30.1
00:12:28
billion danish crooner about 4.5 billion
00:12:30
at the time which equates to roughly 6.9
00:12:33
billion dollars today broadly speaking
00:12:35
the orrison bridge has been a great
00:12:36
success and in its busiest year in 2017
00:12:40
on average just over 20 000 cars passed
00:12:42
over the bridge every day and roughly 14
00:12:45
000 rail commuters passed across the
00:12:47
orison sound since its opening nearly
00:12:49
250 million people have crossed the
00:12:51
orison bridge either by car or rail it
00:12:53
is however not cheap to drive on the
00:12:55
toll cost for a single trip currently is
00:12:58
50
00:12:59
though there are considerable discounts
00:13:01
for frequent users with this kind of
00:13:02
pricing it's not surprising that the
00:13:04
bridge will have effectively paid for
00:13:06
itself by the year 2030. this is a
00:13:09
wonderful bit of engineering which broke
00:13:11
countless records for size and distance
00:13:14
it was a project that faced serious
00:13:16
hurdles because of its location but one
00:13:17
which engineers and designers were able
00:13:19
to safely navigate around as i said
00:13:21
right at the start of today's video this
00:13:24
is one mega project that really gives
00:13:25
you a sense of grand achievement and
00:13:28
where humans have pushed the boundaries
00:13:30
of what's possible and as we've seen
00:13:32
this is a bridge that's so much more
00:13:33
than just a bridge so i really hope you
00:13:35
enjoyed this video if you did please
00:13:37
don't forget to check out side projects
00:13:39
it's the sister channel of this channel
00:13:41
mega projects where we cover things on a
00:13:43
smaller scale that are no less
00:13:45
interesting find a link to it below and
00:13:47
thank you for watching
00:13:48
[Music]
00:13:57
[Music]