Øresund Bridge connects the Danish capital with the Swedish city of Malmö. This unusual structure combines two railway tracks and a four-lane motorway, crosses the Øresund Strait and partially passes under water (tunnel).
A bird’s eye view of the Øresund Bridge offers an amazing view – hanging over the water surface, it seems to crash into a small island and go under the water to “emerge” again after 4 km.
A little background
For many years, residents and visitors of the Scandinavian countries have crossed the Øresund Strait by ferry. It was the only way to get from one bank to the other, but it was not convenient and fast enough. In addition, at the beginning of the 20th century, ferries running between Denmark and Sweden could no longer cope with the volume of passenger and freight traffic. That is why in 1936 the idea of building the Øresund Bridge was announced.
First, the development of the project was prevented by the Second World War, then – by disagreements between the governments of Denmark and Sweden. They saw the implementation of the project in different ways.
They were able to agree and even sign a cooperation agreement only in 1973, but the economic crisis again slowed down all work. The new agreement was signed only 18 years later.
Bridge construction – features of the project and the complexity of its implementation
While working on a project, engineers and architects had to face a major challenge.
As a result of complex calculations, the height of the bridge pylons in the form of pylons was 204 m. However, it was not possible to install them off the coast of Denmark. This was unsafe for aircraft landing at Kastrup airport. It was also impossible to lower the Øresund bridge, so as not to disrupt navigation in the area.
Then the bridge supports were proposed to be transferred to the island of Saltholm. But this option turned out to be unpromising.
- First, for the construction of railways and highways, it would be necessary to fill up the island in order to connect it to the mainland.
- Secondly, construction work would seriously disrupt the local ecosystem.
The solution to the problem turned out to be unusual, but very practical – the bridge was hidden in a tunnel under water , and the soil dug from it was used to create an artificial island of Peberholm. It is here that the Øresund Bridge goes under water, and then effectively appears on the Kastrup Peninsula.
As a result, ships almost always pass over the tunnel and planes land without any hindrance.
The construction of the crossing lasted from 1995 to 1999 and was not without incidents. 16 unexploded bombs from the Second World War were found on the seabed, and the already assembled segment of the tunnel was skewed. But this did not stop the construction of one of the most unusual bridges in the world from being completed 3 months ahead of schedule.
Design features of the Øresund bridge
Almost 100,000 different vehicles cross the Øresund Bridge every day. It is included in the Top 3 of the longest crossings in Europe.
The Øresund bridge is cable-stayed . Every 140 m it is supported by powerful concrete pillars, and two pairs of pylons with a height of 204 m form the central navigable span section. Steel cables run from them to the roadbed, which take on most of the static and dynamic loads.
The length of the bridge in parts (from Sweden to Denmark):
- Surface part – 7 845 m.
- Ground part on Peberholm Island – 4,055 m.
- Tunnel (underwater part) – 4,050 m.
- The ground part on the Kastrup Peninsula is 430 m.
In Denmark, the bridge “leaves” in the eastern part of Copenhagen and is located near the airport.
Øresund Bridge between Denmark and Sweden in numbers:
- weight – 82,000 tons;
- maximum permissible load – 13,602 tons;
- the height of the navigable span – 57 m;
- width – 24 m.
The cost of the Øresund Bridge project was about 4 billion euros! It should pay for itself by about 2035.
The artificial island of Peberholm has a length of a little more than 4 km and a width of about 500 m. The building material for it was fragments of rocks and soil extracted from the bottom of the strait.
Over the years of the bridge’s existence, this man-made island has already formed its own ecosystem. More than 500 species of plants have successfully taken root here, as well as small rodents, three dozen different birds.
Scientists put a lot of effort into maintaining and studying the local flora and fauna. Once a year, biologists have the right to visit Peberholm and go beyond the Øresund Bridge. The rest of the people are strictly prohibited.
Interesting fact! “Peberholm” is translated as “Pepper Island”. The Danes gave it such an original name. The fact is that they decided to supplement the name of the neighboring island of Saltholm, which translates as “Salt Island”. As the Danes understand it, pepper and salt always coexist on the table, just like these two islands.
The length of the underwater tunnel is 3,510 m; bridge approaches take another 270 m. For its construction, 20 separate sections weighing 55,000 tons each were lowered into a canal at the bottom of the strait.
The tunnel consists of 5 “pipes”: two – for vehicles, two more – for railway transport and one for emergencies.
It takes just 50 minutes by car and 25 minutes by high-speed train to cross the Øresund Bridge from one bank to the other. But you will have to pay for the fare regardless of the type of transport, be it a bicycle, bus or truck. It is at the expense of these funds that the construction of the crossing pays off and its working condition is maintained.