When the Rendsburg Canal Tunnel opened on July 25, 1961, people in the region were relieved. Despite the bridge, drivers had to bring time and patience to cross the canal.
by Christian Wolf
The Kiel Canal (NOK) has been connecting the North Sea with the Baltic Sea for more than 125 years. Schleswig-Holstein has been divided ever since. So that people can continue to pass the artificial waterway without any problems, several bridges have been built in the state over the years, including in Rendsburg. After the canal was widened in 1912, the road swing bridge erected in 1895 was replaced by a then modern double swing bridge. It was planned by civil engineer Friedrich Voß, who also built the Rendsburg high bridge, which is why the swing bridge looks like a smaller version of this high bridge. But this structure also has to be replaced after less than 40 years, but this time with a tunnel.
Bridge openings cause traffic jams that stretch for miles
Someone who knows the history of the Channel Tunnel is Uwe Steinhoff. The former naval officer from Kiel has been traveling around the country giving lectures for around 15 years. There are between 100 and 150 a year, and even the German Maritime Museum in Bremerhaven has already booked them. His lectures also deal with the construction of the four-lane crossing under the NOK:"The construction was a mammoth project in which several companies were involved, including Bilfinger, Holzmann AG and Hochtief. The Channel Tunnel was of great importance for the region. " Because not only shipping, but also road traffic increased significantly after the Second World War. "That's why the swing bridge had to be opened several times a day so that the ships could get through. Motorists had to wait and there were traffic jams stretching several kilometers on both sides. Because the regional train also had to cross the bridge," explains the 76-year-old Hobby historian.
Several houses have to be demolished or moved
Uwe Steinhoff is a hobby historian and gives up to 150 lectures a year about the canal, old Kiel and the canal tunnel.The decision was made to build the Channel Tunnel, which started on November 23, 1957. However, space first had to be created in Rendsburg for the project. "On the north side alone, 35 plots of land have been bought. Six houses have to be moved, two of them over 200 meters and they also had to be rotated 90 degrees," explains Steinhoff. The other houses, however, will be demolished. "Then you had to dig a gigantic construction pit on the south side of the canal so that the middle part of the tunnel segment could be built in it." It is 140 meters long and consists of seven concrete parts that are connected to each other with rubber seals. This segment is later to be sunk to the bottom of the NOK at a depth of 20 metres. For this, however, workers and excavators first have to dredge the canal on both banks in a bay-like manner, because the tunnel segment is longer than the canal is wide. "It was simply important that the two exits of the tunnel were outside the canal, so that shipping would not be impeded when building access to the canal," explains hobby historian Steinhoff. In total, man and machine excavate 1.2 million cubic meters of earth for the construction.
Days of lockdown and millimeter work
When the middle section of the tunnel is finally completed, the structure has to be brought to the bottom of the Kiel Canal, sealed at both ends and pumped full of water in order to actually sink. "Twenty hours were planned for this, during which time no ships could pass through the site," but according to Uwe Steinhoff, things turned out completely differently, because the 140-meter-long structure had to be lowered evenly:"For this, the engineers relied on the help of so-called hose water vehicles , because the segment was not allowed to twist and tilt. In addition, pull ropes broke, which divers had to reattach, so the 20 hours ended up being almost 70 hours." The previously dredged bays were now filled in again and provided with a dam. "Now it was only necessary to dig 20 meters deep so that the workers could get to the end of the tunnel entrance and then the access roads to the middle section with a length of 250 meters could be built," says Steinhoff. Even today, motorists passing through the Rendsburg Canal Tunnel notice when they drive over a large grid that is supposed to keep out rainwater.
Opening attracts thousands of visitors
The excavation pit, which was huge for the project, has to be partly filled in later. "But not everything, because the Osterrönfeld outdoor pool is part of the former excavation pit," says Steinhoff. On July 25, 1961, the time had finally come:the Channel Tunnel can be opened to traffic. The celebration becomes a mass event, everyone wants to see the mammoth project of the time. Around 80,000 people flocked to Rendsburg. The starting signal was given by the Federal Transport Minister at the time, Christoph Seebohm, Schleswig-Holstein's Economics Minister, Hermann Böhrnsen, and the Danish Transport Minister, Kai Lindberg. "But before the cars could finally use the four lanes under the canal, people first walked from one end to the other," says the former naval officer.
First tunnel repair in the 1990s
The Channel Tunnel is being renovated for the first time in around 30 years. Among other things, cracks had formed on the walls along the structure under the Kiel Canal, says Uwe Steinhoff. Reinforced concrete and the water - the combination means that "entire parts of the concrete wall have been literally blown away by the rusting of the reinforcement." The areas are treated with rust protection and then sealed again with concrete. "Since the fire protection regulations had changed at the time, fire protection panels were installed in the tunnel," explains Steinhoff. 20 years later the second repair is necessary. But another big problem emerges. According to the amateur historian, the entire Channel Tunnel was not previously examined:"The authorities assumed that the rust damage had doubled and so the tender was issued accordingly. But the tunnel should actually have been closed and completely examined beforehand."
Years of delay and cost explosion
When the fire protection panels are removed, it is found that the entire tunnel is badly damaged on both sides. The lack of documents also delays further rehabilitation points. Modern safety regulations also cause delays. In 2011 work began on renovating the tunnel, and the work should be completed in 2014. But instead of the initially estimated three years of construction, the repairs will take ten years in the end. That is why the 25 million euros provided for this are not enough. In the end, 90 million euros will be due. In the meantime, more precisely since May of this year, and thus in good time before the 60th birthday, traffic can flow again on four lanes under the Kiel Canal. The relief in the region is correspondingly great, whether in business, politics or among commuters. This also shows how important the Channel Tunnel is - even after 60 years.