Great Belt Fixed Link

The Great Belt Fixed Link (Danish: Den faste Storebæltsforbindelse) is the fixed link between the Danish islands of Zealand and Funen across the Great Belt. It consists of a road suspension bridge and railway tunnel between Zealand and the islet Sprogø, as well as a box girder bridge between Sprogø and Funen. The "Great Belt Bridge" (Danish: Storebæltsbroen) commonly refers to the suspension bridge, although it may also be used to mean the girder bridge or the link in its entirety. The suspension bridge, known as the Eastern Bridge, has the world's second longest free span (1.6 km).

The link replaces the ferries which had been the primary means of crossing Great Belt for more than 100 years. After decades of speculation and debate, the decision to construct the link was made in 1986; while it was originally intended to complete the railway link three years before opening the road connection, the link was opened to rail traffic in 1997 and road traffic in 1998. At an estimated cost of DKK 21.4 billion (1988 prices), the link is the largest construction project in Danish history.

The everyday operation and maintenance of the link is done by the company A/S Storebælt under Sund & Bælt. In order to pay back the construction expenses, the road connection is a toll road, and train operators pay a fixed toll per train in order to cross. The link has reduced travel times significantly; previously taking about an hour by ferry, Great Belt can now be crossed in about 10 minutes.

Construction

The construction of the fixed link across the Great Belt became the biggest building project ever in the history of Denmark. In order to connect Halsskov on Zealand with Knudshoved on Funen, 18 kilometres to its west, a two-track railway and a four-lane motorway had to be built, aligned via the small islet Sprogø in the middle of the Great Belt. In general terms, the project comprised three different construction tasks: The Eastern Bridge for road transport, the Eastern Tunnel for rail transport and the Western Bridge for road and rail transport combined.

The Eastern Bridge

Built between 1991 and 1998, the Eastern Bridge (Østbroen) is a road suspension bridge between Halsskov and Sprogø. It is 6,790 metres long with a free span of 1,624 metres, making it the world's second largest suspension bridge, surpassed only by the Akashi-Kaikyo Bridge in Japan. The vertical clearance for ships is 65 metres. At 254 metres above sea level, the two pylons of the Eastern Bridge are the highest points on solid structures in Denmark. (Only some radio masts as Tommerup transmitter are taller).

To keep the main cables tensioned, an anchorage structure on each side of the span is placed below the road deck. Additionally, a total of 19 concrete pillars (12 on the Zealand side, 7 by Sprogø), each separated by a distance of 193 metres, carry the road deck outside the span.

The Western Bridge

The Western Bridge (Vestbroen) is a box girder bridge between Sprogø and Knudshoved. It is 6,611 metres long, and has a vertical clearance for ships of 18 metres. It is essentially two separate, adjacent bridges above water, the northern one carries rail traffic and the southern one carries road traffic. However, the pillars of the two bridges rest on common foundations below sea level. The Western Bridge was built between 1989 and 1994; its road/rail deck is comprised of 63 sections, supported by 62 pillars.

The tunnel

The twin bored tunnel tubes of the Eastern Tunnel (Østtunnelen) are 8 kilometres long each. Between the two main tunnels there have been established 31 connecting tunnels at 250 metre intervals. The equipment that is necessary for train operation in the tunnels has been installed in the connecting tunnels. The connecting tunnels also serve as emergency escape routes.

During construction of the tunnels, the sea bed gave way and one of the tunnel pipes was flooded. The water continued to rise and reached the end at Sprogø, where it continued into the (still dry) other tunnel pipe. The water thus destroyed two of the four drilling machines, but no workers were injured. Only by drilling refrigeration hoses down into the sea bed and freezing the bottom was it possible to dry out the pipes, remove the defunct machines and complete the drilling from the Zealand side.

Traffic implications

Prior to the opening of the link, an average of 8,000 cars used the ferries across the Great Belt every day. In 2004, an average of 23,700 cars travelled the link each day. The increase of the traffic volume is partly caused by the general growth of traffic, partly diversion of traffic volume from other ferry services, and finally the so-called traffic leap, that is, new traffic generated by the improved ease, facility and low price of crossing the Great Belt.

The fixed link has produced considerable time savings for travel and transport between eastern and western Denmark. Previously, the average time consumption involved in car transfer by ferry across the Great Belt was approximately 90 minutes, including the waiting time at the harbours. The time consumption was considerably higher during peak volume periods, that is, weekends and holidays. After the opening of the Great Belt Link, the time consumption has fallen to approximately 10 to 15 minutes.

For those who travel by train, the time savings are even greater. The travel time has been reduced by 60 minutes, and there are many more seats available than previously, because more railway cars may be added to a train as this train does not have to fit onto a ferry. The total seating capacity offered by DSB across the Great Belt on an ordinary Wednesday has risen from 11,060 seats to 37,490 seats. On Fridays the seating capacity exceeds 40,000 seats.

On the following stretches the shortest travel times are as follows: Copenhagen-Odense 1 hour 15 minutes, Copenhagen-Aarhus 2 hours 30 minutes, Copenhagen-Aalborg 3 hours 55 minutes and Copenhagen-Esbjerg 2 hours 35 minutes.

The air connection Copenhagen-Odense has been closed down, and the train has taken a leading market share between Copenhagen-Aarhus.

In an international perspective, the link - together with the Oresund Bridge - provide a direct fixed connection between western Continental Europe and northern Scandinavia.

Environmental effects

Environmental considerations have been an integral part of the construction project of the fixed link across the Great Belt, and have been of decisive significance for the choice of alignment and determination of the design of the construction. Environmental considerations were the reason why the Great Belt A/S established an environmental monitoring programme in 1988, and initiated co-operation with authorities and external consultants on the definition of environmental concerns during the construction work and the professional requirements to the monitoring programme. This co-operation issued in a report published at the beginning of 1997 on the state of the environment in the Great Belt. The conclusion of the report was that the marine environment was at least as good as before the construction work began.

As concerns the water flows, the Great Belt Link must comply with the so-called zero-solution. This has been achieved by deepening parts of the Great Belt, so that the water flow cross section has been increased. This excavation compensates for the blocking effect caused by the bridge pylons and approach ramps. The conclusion of the report concerning the water flows is that the flow is now almost at the level it was at before the bridge was built. The fixed link across the Great Belt has generated increased road traffic volume, which in itself has meant increased air pollution. However, there has been significant savings in the energy consumption of the east-west traffic by switching from ferries to the fixed link. Train and car ferries consume much energy for propulsion. High-speed ferries consume large amounts of energy at high speeds. Also air transport is highly energy consuming.

The larger energy consumption by ferry transport as opposed to transport via the fixed link is most clearly seen when comparing short driving distances from areas immediately east or west of the link. For more extended driving distances the difference in energy consumption is smaller, but any transport within Denmark’s borders that goes east-west across the link shows very clear energy savings.

Accidents

The Western bridge has been crashed into twice. While the link was still under construction on September 14, 1993, the ferry M/F Romsø drifted off course in bad weather and hit the Western bridge. At 19:17 on March 3 2005, the 3,500-ton freighter M/V Karen Danielsen crashed into the Western bridge 800 metres from Funen. All traffic across the bridge was closed, effectively separating Denmark in two. It was re-opened shortly after midnight, after the freighter was pulled free and inspectors had found no structural damage to the bridge.

The Eastern bridge has so far been in the clear, although on May 16, 2001, the bridge was closed for 10 minutes as the Cambodian 27,000-ton bulk carrier "Bella" was heading straight for one of the anchorage structures. The ship was deflected due to a swift response from the navy.

On June 5 2006, a maintanence vehicle burst into flame in the east-bound railway tunnel at about 21:30. Nobody was hurt; its crew, three men, fled to the other tunnel and escaped. The fire was put out shortly before midnight, and the vehicle was removed from the tunnel the next day. Train service was also resumed on June 6, at reduced speed, however. Normal service was expected to resume on June 12 2006.

External links

Great Belt Bridge
Image
Map
Satellite photo from Google Maps
The Great Belt Bridge nearly hit by cargo ship from the Ingeniøren magazine, May 16, 2001 (in Danish)
Rammed ship: Skipper was drunk from News24, describing the March 3, 2005 collision
Mate was intoxicated; similar news story from DR, with additional background (in Danish)
http://en.structurae.de/structures/data/index.cfm?ID=s0000031
http://en.structurae.de/structures/data/index.cfm?ID=s0002357

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