Great Belt Bridge: The Infrastructure that Linked Denmark and Changed Europe

If Europe were to be told through its infrastructures, the Great Belt Bridge (Storebæltsbroen in Danish) would occupy one of the central chapters. Like the Mont Blanc tunnel or the Gotthard tunnel, or the tunnel crossing the English Channel, or even the high-speed rail networks that connect the main cities of the continent, the bridge that links the Danish islands of Zealand and Funen is certainly a symbolic work, as well as a major accelerator of development.

Those 18 kilometers that have redefined mobility, the economy, and the identity of an entire nation represent first and foremost a masterpiece of applied engineering, an example of advanced structural design, environmental resilience, and geopolitical vision.

The Great Belt connection is in fact an integrated infrastructural system, consisting of three main sections:

– a cable-stayed bridge of 6,790 meters between Zealand and the small artificial island of Sprogø;
– an underwater railway tunnel 8,024 meters long between Sprogø and Funen;
– a second steel arch bridge of 6,611 meters connecting Sprogø to Funen for vehicular traffic.

The heart of the entire system is the East Bridge, a 6,790-meter-long cable-stayed bridge, which with its 1,624-meter main span is still one of the longest suspension bridges in the world. Its reinforced concrete towers reach 254 meters in height, making it the tallest structure in Denmark.

The Great Belt Bridge was designed to withstand extreme environmental conditions: winds over 55 meters per second, high marine salinity, significant temperature variations, and the daily transit of thousands of vehicles and trains.

The bridge foundations rest on piles anchored to the seabed up to 40 meters deep, capable of ensuring stability even in the event of seismic activity or accidental impacts, while the towers are built with prefabricated concrete segments, assembled with millimetric precision. The use of modular technologies made it possible to speed up the construction of the project and ensure the dynamic stability of the entire structure.

Among the project’s key players stands out the Danish firm Cowi, a world leader in the design of complex infrastructures, involved in all phases of the study, from environmental analysis to structural design, from aerodynamic simulations to the study of marine currents.

Throughout its history, Cowi has signed off on some of the world’s most iconic infrastructures, including the Queensferry Crossing in Scotland, the Stonecutters Bridge in Hong Kong, the Millau Viaduct in France, and the recent Fehmarnbelt Tunnel project between Denmark and Germany. Today, it is also among the designers of the future Strait of Messina Bridge, which will connect Calabria to Sicily, becoming the longest suspension bridge in the world.

Since its opening in 1998, the Great Belt Bridge has radically transformed mobility between Denmark’s two wealthiest regions, reducing travel time from over an hour to less than 15 minutes. Traffic, both automotive and rail, has not only increased in volume but has also gained in regularity and reliability.

Currently, over 35,000 vehicles cross the bridge every day, while high-capacity trains run more than 80 daily services.

Economically, the infrastructure construction has generated a national GDP increase estimated at around 0.3% per year, thanks to improved logistical connections and the growth of domestic trade. It has also encouraged commuting and integration between the eastern and western regions of the country, contributing to greater social and territorial cohesion.

The project, with a total value of around 21 billion Danish kroner (equivalent to over 2.8 billion euros today), was financed through state-guaranteed loans and is being repaid through tolls, with full financial sustainability expected by 2030.

In addition to its impact on the Danish economy, the Great Belt is a strategic hub for the entire Scandinavian-Mediterranean TEN-T corridor, which connects Norway to Italy via Denmark, Germany, and Austria. Thanks to its efficiency, the infrastructure has drastically reduced maritime transport between the Danish islands and encouraged rail transport, contributing to the decarbonization of the European transport system. It has also opened new maritime trade routes between Sweden, Denmark, and Germany, integrating ports like Gothenburg and Hamburg into a more efficient continental logistics network.

From an environmental point of view, the project was one of the first in Europe to include an ecological compensation plan and long-term marine monitoring. Even today, marine currents and biodiversity in the area are studied to ensure the balance of ecosystems.

Moreover, the infrastructure is equipped with an advanced continuous structural monitoring system that enables predictive maintenance, reducing costs and ensuring safety.

For all these reasons, the Great Belt Bridge represents a case study for engineers, economists, and structural engineers, because it has not only shown that it is possible to build large projects in complex marine environments, but has also highlighted the importance of infrastructures designed to generate long-term value.

This bridge’s legacy in infrastructure engineering lives on in future projects, such as the Strait of Messina Bridge, designed to meet the same challenges.