Pourquoi Personne n'a Construit de Pont Entre l'Europe et l'Afrique

Sympa

Construire un pont entre l'Europe et l'Afrique semble incroyable, mais c'est beaucoup plus compliqué qu'il n'y paraît. Le détroit de Gibraltar, où les deux continents sont le plus proches, fait environ 8 miles de large, mais l'eau y est extrêmement profonde - jusqu'à 3,000 pieds à certains endroits ! En plus de cela, la région est très venteuse et présente de forts courants, ce qui rend la construction encore plus difficile. Les ingénieurs ont proposé des idées, comme des tunnels flottants ou des ponts suspendus très longs, mais cela coûterait une fortune et poserait encore d'énormes défis techniques. Les défis politiques et économiques entrent également en jeu, car un tel pont nécessiterait la coopération de plusieurs pays. Pour l'instant, les ferries font le travail, et la plupart des gens les trouvent suffisamment pratiques.  Animation créée par Sympa. ---------------------------------------------------------------------------------------- Musique par Epidemic Sound https://www.epidemicsound.com   Pour ne rien perdre de Sympa, abonnez-vous!: https://goo.gl/6E4Xna​ ---------------------------------------------------------------------------------------- Nos réseaux sociaux : Facebook: https://www.facebook.com/sympasympacom/ Instagram: https://www.instagram.com/sympa.officiel/  Stock de fichiers (photos, vidéos et autres): https://www.depositphotos.com https://www.shutterstock.com https://www.eastnews.ru ----------------------------------------------------------------------------------------  Si tu en veux encore plus, fais un tour ici:  http://sympa-sympa.com

Transcript

00:00So look at this narrow passage between the north of Morocco and the southern part of Spain.

00:06This is the Detroit of Gibraltar.

00:09There is only 13 km between the two continents.

00:12But for one reason or another, there is no bridge.

00:15While people have been dreaming for centuries to connect these two regions.

00:20In some parts of the world, bridges have been built over much larger distances above the water.

00:25For example, the ground of Lake Pontchartrain, near New Orleans, in Louisiana,

00:30extends over 38 km,

00:32which is three times the length of the hypothetical bridge between Africa and Europe.

00:37It appears in the Guinness Book of Records

00:39as the longest continuous structure built above a water extension.

00:43It consists of two parallel bridges

00:45and connects the urban area of New Orleans to the small town located north of Lake Pontchartrain.

00:519,000 concrete piles support more than 1,000 sections above the water.

00:56This gigantic structure was built in the middle of the 20th century.

01:00It took only 14 months between the start of its construction and its completion.

01:05American engineers used an unprecedented technology

01:08to fix the concrete piles at the base of the bridge.

01:11And this bridge is still in operation.

01:13So what is the problem with the construction of a bridge that would connect Africa and Europe?

01:18Let's first discover the advantages that this 13 km bridge would bring

01:22by connecting the two continents and the reason why everyone is talking about it.

01:26Well, it would be priceless.

01:29Diamonds, oil, minerals.

01:31Africa is full of precious materials.

01:34And Europe only asks to buy them.

01:37This theoretical bridge would allow to transport quickly and easily

01:40all kinds of goods for trade.

01:44And today, the exchange of goods between Africa and Europe

01:47is only possible thanks to planes and cargo.

01:50And planes are extremely expensive due to the high price of fuel.

01:56In addition, flights are often delayed due to bad weather.

02:00The customs procedures take time

02:02and the distances between airports and urban centers are important.

02:08Boats can also be a problem.

02:10The area of the Mediterranean where the two continents are close to each other

02:13is dangerous due to storms and strong currents.

02:16The transport of your diamonds therefore depends heavily on weather conditions.

02:23The second advantage of such a bridge would be the creation of tens of thousands of jobs.

02:27Europeans and Africans would build hotels, ports, parks and even small towns together.

02:34The coastal regions of the two continents would become new economic centers.

02:39And imagine the investments that these places would attract.

02:44Europe and Africa would be closer than ever.

02:47You could go by car from a Spanish city to a safari park in the north of Morocco,

02:52buy Moroccan tea, Argan oil and go home the same evening.

02:57You could also take a high-speed train to cross the magnificent Mediterranean Sea.

03:02Hundreds of restaurants, amusement parks, shopping centers and museums

03:06could be built nearby.

03:08But unfortunately, it is impossible to build such a bridge.

03:12At least at the moment. And here is why.

03:16The main problem is the Strait of Gibraltar itself,

03:20its strong currents and its seismic activity.

03:23How to launch a large-scale construction if, in a few days,

03:27an earthquake can trigger giant waves and take all the ships under water?

03:32Even if you build a bridge.

03:35Fast water currents that constantly change direction

03:38could shake the whole structure and damage its foundations.

03:43The bridge over the Strait of Gibraltar should be designed

03:46according to a method capable of resisting seismic activity.

03:50And huge resources would be necessary to create something so complex.

03:55Despite the danger that the passage between these two continents represents,

03:58this region remains one of the most frequented in the world.

04:01It is the only place on the planet where the Mediterranean Sea and the Atlantic Ocean meet.

04:06About 300 ships pass through it every day.

04:10Merchant ships, but also fishing and tourism boats.

04:15There are not many places in the world where you can observe whales coming out of the water.

04:20Because of the peculiarities of the marine currents of this area,

04:23this strait is frequented not only by people, but also by marine creatures.

04:28We will talk about this later.

04:30Another problem is the depth of the strait.

04:33In concrete terms, any bridge crossing a stretch of water must rest on long metallic piles.

04:38Builders and engineers plant these piles in the seabed

04:41and use them as a maintenance base for the entire construction.

04:45But it is difficult to fix these piles in a sufficiently stable way

04:49due to the irregularity of the underwater soil.

04:52Its geology presents unique characteristics,

04:55irregularities and different densities of terrestrial rocks.

04:59There are also reefs, rocks and ditches.

05:02Any seabed requires in-depth geological studies before the installation of piles.

05:07And the bottom of Gibraltar's strait is particularly difficult to access because of its depth.

05:13Almost 915 meters.

05:15It is one of the deepest straits in the world.

05:18Imagine, you could stack ten Statues of Liberty between the bottom of the strait and the surface of the water.

05:24What kind of piles should be used in this place to support an entire bridge?

05:29Probably piles made up of several sections connected to each other by a long metal rod.

05:36Do not forget the seismic activity either.

05:39Suppose you have installed perfectly robust piles,

05:42but that the next day, an earthquake occurs and destroys the entire structure.

05:47In addition, strong currents would carry the debris all over the Mediterranean.

05:53The third problem is the most important.

05:56Because it concerns marine life.

05:58The strait of Gibraltar has a strong salt content.

06:01This natural element weighs down the water,

06:04and a whole layer of very salty water occupies the bottom of the deep Mediterranean basin.

06:08This salty water pushes the cold water from the seabed towards the Atlantic Ocean.

06:13These changes in density, as well as rapid currents,

06:17create continuous turbulence.

06:20It is like a cold water cauldron that would raise a lot of nutrients to the surface.

06:26The depressions and elevations of the strait of Gibraltar are filled with various substances and sunlight.

06:33Ideal conditions for the formation of phytoplankton.

06:36Whales, dolphins and other marine creatures love this delicate seabed.

06:42This is why there are about seven species of whales and dolphins here.

06:46What would happen to the phytoplankton after the start of construction?

06:50Carbon dioxide, crushed rocks, tons of dust and ash,

06:54the fall of building materials,

06:57all of this would considerably pollute the environment.

07:00Without phytoplankton, many fish would disappear.

07:03Without fish, thousands of fishermen would no longer be able to feed themselves and earn money.

07:08And if this bridge ended up being built,

07:10cars and trains would continue to pollute the air and water.

07:14The disturbance of the fragile balance of this narrow strait

07:17could lead to large-scale environmental disasters.

07:21Dolphins and whales would go looking for food elsewhere

07:25and, as a result, would disturb the ecosystem of other marine regions.

07:29Like falling dominoes, one problem would lead to another.

07:33And all this because of one bridge.

07:35In 2007, the Spanish Ministry of Environment Protection

07:39established speed limits for all vessels

07:42using the strait in order not to disturb the fragile balance of nature.

07:48In the early 20th century, a French engineer proposed a bridge project,

07:52but it was rejected because it was too complicated and too expensive.

07:57A 37-kilometer-long tunnel was also attempted,

08:01but this project faced financial and technical difficulties.

08:05People still dream of a bridge over the Gibraltar Strait.

08:09Maybe one day, when we have developed our technologies,

08:12we will be able to build it.

08:16Besides, there has not always been water between these two regions.

08:20A very long time ago, these two continents were interlinked.

08:24The Mediterranean Sea is the remains of the Tethys,

08:28a paleo-ocean from the time of the dinosaurs.

08:31At one time, the African and Indian plates collided with the Eurasian plate,

08:36and the Tethys completely disappeared.

08:38Instead, a terrestrial bridge formed, separating the Mediterranean Sea from the ocean.

08:45Without water, the sea dried up about 6 million years ago.

08:50But when this natural bridge collapsed, the water came back to fill the basin.

08:55Its narrow plate sank for tens of thousands of years,

08:59and the Mediterranean Sea finally reached its current level.

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