Engelberg tunnel
 Engelberg tunnel
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 North portal of the Engelberg base tunnel (June 2006)
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| use | Motorway tunnel | |||
| traffic connection | Federal highway 81 | |||
| place | Engelberg near Leonberg | |||
| length | 2530 m | |||
| vehicles per day | 110,000 | |||
| Number of tubes | 2 | |||
| construction | ||||
| start of building | July 25, 1995 | |||
| completion | August 12, 1999 | |||
| location | ||||
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| Coordinates | ||||
| South portal | 48 ° 47 ′ 10 " N , 9 ° 0 ′ 59" E | |||
| North portal | 48 ° 48 '12 " N , 9 ° 2' 17" E | |||
Map with all coordinates: As Engelberg tunnel , the motorway tunnel Age Engelbergtunnel and his successor structure, the Engelberg base tunnel , respectively. Both tunnels on Autobahn 81 are near Leonberg in the Stuttgart region .
The Engelberg base tunnel crosses under the Engelberg east of Leonberg as part of the federal highway 81 Stuttgart - Heilbronn .
Old Engelberg tunnel
The first Engelberg tunnel was opened to traffic on November 5, 1938 after a construction period of three years. It was part of the Reichsautobahn route 39. With a length of 318 m and two tubes, it was the second motorway tunnel in Germany after the 60-meter-long Nasenfels tunnel (released October 30, 1937; today A 8 ).
During the Second World War it served as the Messerschmitt AG factory from 1944 . Forced laborers brought to Leonberg from the Natzweiler-Struthof concentration camp in Alsace assembled aircraft wings for the Me 262 here in twelve to eighteen-hour shifts . For this purpose, a false ceiling was installed to increase the production area to 11,000 m². Of the approximately 3,000 forced laborers in the Leonberg concentration camp, 374 died. Shortly before the end of the war, the machines were dismantled and the pipes blown up.
The first tube was restored between 1946 and 1950, the second in 1960/1961.
After the commissioning of the successor structure, the eastern tube was completely filled with overburden from the new tunnel. The west tube of the old tunnel was initially retained; the federal government transferred it to the city of Leonberg, which wanted to keep open the option of a bypass road through the tunnel; however, this was never realized. The western south portal was later included in a memorial for the concentration camp, all other portals were covered with soil. The old section of the motorway has been renatured.
After the regional council of Stuttgart expressed doubts about the stability of the tunnel vault in October 2004 , both tubes were opened for inspection in May 2006. As experts certified that the two tunnels were not in a stable position, work began on October 8, 2007 to almost completely fill and grout the old tunnel structure. A 20 m long section of the west tube at the south portal was preserved as part of the memorial. The costs for this were estimated at around one million euros and the work was completed in spring 2008.
A passage through the tunnel can be seen in the opening credits of the 1968 television series Spedition Marcus .
Western south portal of the old Engelberg tunnel and concentration camp memorial (July 2005)
East tube temporarily opened in October 2007
Engelberg base tunnel
The old tunnel with two lanes each (without a hard shoulder) had been an obstacle for a long time, especially for heavy traffic, while the A 81 north of Engelberg to Heilbronn had already been developed into three lanes with verges. The problem was not only the two-lane in the tunnel, but also the incline of the two-lane access ramps. On the ramps with gradients of up to 6%, the heavy goods vehicle only reached low speeds, so that mostly only the passing lane was available for passenger cars. With a traffic load of 83,000 vehicles within 24 hours, at peak times up to 120,000, traffic jams were commonplace.
Initial plans to improve traffic flow came from the 1970s. Initially, consideration was given to widening the existing tunnel tubes or adding a third tube. In view of the disadvantages (steep incline of the ramps, the motorway cuts through the city), a new solution was found: The Engelberg base tunnel is about 60 m below the old tunnel, its access roads are practically at ground level. The gradient from the north to the south portal is only 0.9%. Each of the two tunnel tubes contains three lanes and a hard shoulder with a reduced width.
The construction project was included in the requirement plan for federal trunk roads in 1975. A 1 km long exploratory tunnel provided information about geological peculiarities and possible problems during construction in 1977/78. Among other things, mountain water with a high sulphate content was found that can attack concrete. In addition, it was shown that the Engelberg also contains swellable minerals such as anhydrite . In 1981, a 20 centimeter thick layer of shotcrete was destroyed after surface water penetrated an improperly sealed exploratory well.
Construction of the Engelberg Base Tunnel began on July 25, 1995 . The tunnel breakthrough of the east tube took place on July 4, 1997, the west tube on September 15, 1997. On September 11, 1998, the east tube was opened to traffic. Initially, all traffic in both directions was routed through this tunnel until normal operations began on August 12, 1999 with the opening of the western tunnel. Both tunnel tubes are each 2530 m long. Tunnel transmitters mean that radio and mobile communications can also be received in the tunnel. Taking into account the development on the south side of Engelberg, the exhaust gases are blown out of the tunnel near the north portal. During the same period the Leonberg motorway triangle was rebuilt.
Instead of the originally planned DM 604 million , the construction cost DM 850 million (price as of 1999, today's equivalent: 580 million euros ). The additional costs are due, among other things, to reinforced reinforcement of the tunnel walls in order to counter the swelling anhydrite. The project was financed privately by a construction consortium, which assigned the demands for completion to a bank consortium. The state of Baden-Württemberg paid the construction costs and the EURIBOR- based interest in 15 annual installments until 2014 . Including interest, the state of Baden-Württemberg calculated costs of 1.24 billion DM (price as of 1999, today's equivalent: 846 million euros). The high costs for this financing model and the resulting restrictions for other construction projects have generated a lot of criticism. The then Federal Transport Minister Matthias Wissmann , however, argued that the public sector could not have financed the project and that the construction time had been reduced from eight to five years.
The tunnel is used by around 110,000 vehicles per day (as of 2016). From 2017, a conversion of the operational and a renewal of the traffic technology was planned.
Renovations
The geological conditions, in particular the swelling of the anhydrite , put a heavy strain on the structure of the tunnel, so that since the opening of the two tubes in 1999 the tunnel had to be renovated three times by 2010. In 2006 and 2008 repairs were carried out for one million euros. In 2010, concrete slabs were removed from the tunnel walls over a length of 130 m (east tube) and 150 m (west tube), thus reducing the pressure caused by swelling rock.
After cracks and deformations were found in the tunnel wall over a length of around 200 m, renovation to the amount of 110 million euros is planned from 2018 to 2023. All lanes should be available. Lanes are planned to be closed at night and on weekends. Calcium sulphate was found over a length of 450 m, 175 m of which are considered endangered. In this area, the deck slab is to be reinforced and a steel framework is to be drawn into the walls and ceiling and filled with concrete. The work should run around the clock and be financed by the federal government. The preparations for the renovation, which cost 20 million euros, began in summer 2016. The construction work in the tunnel tubes is to run from April 2020 to 2024.
literature
- Concentration camp documentation center in the old Engelberg tunnel in Leonberg. An exhibition. Edited by the Leonberg eV Concentration Camp Memorial Initiative, Holger Korsten and Eberhard Röhm , Leonberg 2010, ISBN 978-3-00-032802-2 .
- The Natzweiler-Struthof concentration camp in the Vosges and its satellite camps in Baden, Württemberg and Hohenzollern. A handout for visiting the memorial sites (incl. CD-ROM with additional images, documents, texts and teaching suggestions). Published by the State Center for Political Education Baden-Württemberg in collaboration with the State Working Group on Memorials in Baden-Württemberg. Acquired by Eva Bernhardt, actual. by Sibylle Thelen, Torsten Liebig. Red .: Eberhard Röhm, Konrad Pflug. 2nd, updated edition, LpB, Stuttgart 2014, ISBN 978-3-945414-10-1 .
Web links
Individual evidence
- ↑ Leonberger Kreiszeitung from November 7, 10 and 16, 2007.
- ↑ Press release of the Stuttgart Regional Council from May 3, 2006.
- ↑ Leonberger Kreiszeitung from November 24, 2006: City wants to close the old tunnels after all ( memento of the original from February 24, 2013 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. .
- ↑ Stuttgarter Nachrichten of October 5, 2007.
- ^ Spedition Marcus , episode 5, November 30, 1968.
- ↑ a b c d The Engelberg base tunnel and the reconstruction of the Leonberg motorway triangle, civil engineering 10/1998 ( PDF ( Memento of the original from January 8, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and Archive link according to instructions and then remove this note. ).
- ↑ http://de.structurae.de/structures/data/index.cfm?id=s0000673 .
- ↑ a b c Application by Abg. Claus Schmiedel and others SPD and statement of the Ministry for Environment and Transport: Engelberg financing and its consequences. Printed matter 12/4315 (PDF; 37 kB) State Parliament of Baden-Württemberg. August 9, 1999. Archived from the original on October 19, 2013. Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved January 10, 2011.
- ↑ Redevelopment of millions as a greeting to Stuttgart 21 ( memento of the original from September 20, 2017 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. . Stuttgarter Nachrichten of August 21, 2010.
- ↑ Birgit Klein: 10 years Engelberg Tunnel: A city breathes again . Stuttgart news. September 9, 2009. Archived from the original on August 8, 2010. Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved January 10, 2011.
- ↑ Norbert F. Pötzl , Wolfram Bickerich : I have a vision . The mirror . September 1, 1997. Retrieved January 10, 2011.
- ↑ Engelberg Tunnel: Two tubes, one bottomless barrel . In: Stuttgarter Nachrichten of September 8, 2010.
- ↑ a b Hans Georg Frank: Cracks in the tubes . In: Swabian Post . October 20, 2016, p. 6 ( online ).
- ^ RP Stuttgart press release. In: rp.baden-wuerttemberg.de. Retrieved October 20, 2016 .
- ↑ Alexander Ikrat: In the tunnel under the Engelberg tunnel . In: Stuttgarter Nachrichten . tape 74 , January 9, 2019, p. 19 (online at stuttgarter-zeitung.de ).
