Letzigraben Bridge

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Construction work on the bridge in November 2013
Letzigrabenbrücke seen from the Hardbrücke

The Letzigrabenbrücke is within the so-called diameter line Altstetten-Zurich HB-Oerlikon created (DML) bridge structure . The bridge , which was completed in 2015 and is located in the forecourt of Zurich's main train station, is the longest (single-lane) railway bridge in Switzerland at 1156 meters.

Together with the coal triangle bridge , it forms the exit from the new, underground Löwenstrasse station towards the west: the 394 meter long coal triangle bridge connects to the exit from the Löwenstrasse station and extends to the Hardbrücke . For the crossing under the Hardbrücke, the railway line runs at the level of the existing track systems. The Letzigrabenbrücke continues the route for westbound trains to Altstetten station and crosses the entire track field of the forecourt as well as the Duttweilerbrücke , a road bridge over the track field. Trains in the opposite direction can use existing tracks.

The construction work began in 2008 with the laying of high-voltage lines from the construction site. The first of the 23 pillars were erected in 2009 . The pillars, a maximum of 16 meters high, are based on bored piles up to 45 meters long . The superstructure was built using a feed scaffold that was installed in autumn 2011.

In November 2013, a serious construction flaw was discovered during a routine inspection: the concrete of the bridge trough showed fine cracks above the pillars. The reason for this lies in the structural detail that the bearings on which the bridge trough rests are slightly shifted inwards for aesthetic reasons: “The forces from above from the supporting structure and those from below do not meet at one point; the lateral difference causes a bending moment on the trough plate. Because this flow of forces has not been taken into account, this plate is dimensioned too weakly. It bends upwards ... ».

This static error was eliminated without any major external changes to the bridge and without any time delays: “Six to eight tensioning cables are drawn across the roadway over each of the 30 piers and fixed on the outside with anchor heads. Each cable is pre-tensioned with 220 tons of tension. The tension cables prevent the base plate from bending upwards. " The 30 pillars mentioned include the seven pillars of the coal triangle bridge, with which the problem also existed.

The tensioning cables resting on the bridge trough had to be concreted in, which meant that a conventional ballasted track could no longer be installed due to the lack of space . Therefore, for the first time in Switzerland, a slab track from the LVT system (as in the Weinberg tunnel ) was installed outside a tunnel .

The construction costs of the Letzigraben and Kohlendreieck Bridge, which was officially opened on October 26, 2015 and started operating on December 13, 2015, totaled around CHF 300 million .

literature

  • Tages-Anzeiger , January 25, 2008, regional section Zurich City, p. 63.

Web links

Commons : Letzigrabenbrücke  - collection of images, videos and audio files

Individual evidence

  1. ↑ a b Peter Rahm: Zurich Diameter Line puts second stage into operation . In: Fachkom GmbH (Ed.): The construction sites . Issue 12. Fachkom GmbH, Langnau am Albis December 2015, p. 62-66 .
  2. ↑ a b c Ruedi Baumann: Too graceful to be stable. In: Tages-Anzeiger. August 28, 2014, accessed November 4, 2016 .
  3. ↑ watson.ch: That will be expensive: SBB have to improve bridge for cross-city line in Zurich
  4. ↑ Swiss premiere for LVT on long bridges. Vigier Rail AG, September 15, 2015, accessed on November 4, 2016 .
  5. ^ Bye-bye dead end. In: Tages-Anzeiger of October 26, 2015.
  6. ↑ The quick-change artist. In: Tages-Anzeiger from October 25, 2015.

Coordinates: 47 ° 23 ′ 13 "  N , 8 ° 30 ′ 25"  E ; CH1903:  six hundred and eighty thousand six hundred and sixty-one  /  249,012