Bypass Saas

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upper end / beginning of the bypass in August 2010

The Saas bypass at Hauptstrasse 28 is part of the expansion of the national road 28 in Prättigau in the Swiss canton of Graubünden . Construction began in 2002 and was opened to traffic on October 21, 2011. Up the valley, the longest section of the upgraded route joins the Klosters bypass ; Down the valley it merges into the Küblis bypass , which was opened in June 2016.

purpose

The purpose of the bypass routes in the Prättigau is to relieve the places along the through road from long-distance traffic, which is especially prevalent in the main winter season. The year-round connection from the Bündner Unterland to the Engadine also plays an important role . Since 1999, the year the Vereina railway tunnel with car transport in Klosters - Selfranga was put into operation , the road through the Landquart valley has been additionally burdened. Before the opening of this tunnel, there was also through traffic into the Engadine, but via the Flüelapass near Davos , which was very difficult to drive safely in winter.

Connection Saas

The Saas half-connection is the western approach to the Walser village of Saas in Prättigau . The route of the old cantonal road branches off from the new line and becomes the access road. The new route continues from here to the immediately following west portal of the Saas tunnel.

Saas tunnel

The Saas Tunnel forms the core of the Saas bypass. After the Gotschna tunnel near Klosters, it is the second longest tunnel of the entire expansion project with a length of 2577 m. It begins at the Saas West portal and rises from there with 2.6% over a length of 2.58 kilometers to the Waldhof tunnel portal in the east. At the same time, as with the Gotschna tunnel, an emergency tunnel was built 30 meters away on the valley side. Eight cross tunnels lead to this at a distance of around 300 meters. In addition, there are three breakdown bays on both sides. LEDs on the banquet and so-called light nails in the middle of the track provide increased security for keeping track in the tunnel. Emergency niches and hand fire extinguishers can be found every 150 meters. Above the ceiling cladding there is a fire duct, an extraction system in the event of smoke development. The tunnel is also monitored by video cameras. A speed limit of 80 km / h applies in both lanes. Thanks to antennas, it is possible to make calls with mobile phones in the tunnel as well as listening to local radio stations. Sensors constantly measure the wind going in the tunnel, recognize clouding of visibility and monitor the CO 2 content of the air. Additionally built-in smoke detectors and a fire alarm cable alert you in good time in the event of smoke and fire incidents and thus enable self-rescue in the rescue tunnel secured by overpressure.

After a 130-meter-long section of open-cast mining after the west portal of the tunnel, a 35-meter-long section in loose rock followed . This was followed by a 2.02 kilometer long section in rock , which was penetrated by blasting. The tunnel then reaches ground moraine material . This was penetrated from the east portal, with a tubular umbrella providing the necessary stability. At the east portal, a twelve-meter-short open-cast section was built.

The safety gallery running parallel to the road tunnel was created using a tunnel boring machine with an excavation diameter of 4.25 meters.

Hexentobel Bridge

Immediately after the Waldhof tunnel portal, the 339 meter long Hexentobel Bridge begins, a Ypsilon bridge standing on the slope. The word Ypsilon indicates the shape of the columns that are open towards the top.

Marchtobel Bridge

Between the Hexentobel Bridge and the Pagrüeg junction, the 86-meter-long Marchtobel Bridge forms the continuation of the upgraded route after the road behind the Hexentobel Bridge runs along the slope for a short time on solid ground. This bridge is also a Ypsilon bridge.

Connection Pagrüeg

The Pagrüeg junction is a roundabout into which the new cantonal road runs to the west and east. To the south the road to Pagrüeg joins the roundabout and to the north joins the east access to Saas. This access corresponds to the old cantonal road, the so-called Prättigauerstrasse.

See also

Web links