Lorraine Bridge

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Lorraine Bridge with the Lorraine Viaduct in the background
Plastic by Paul Kunz
Indoor shot

The Lorraine Bridge connects downtown Bern via the Aare river valley with the Lorraine district to the north .

At the same time, the Lorraine Viaduct is located downstream .

The four-lane road bridge was built between 1928 and 1930 as a replacement for the driveway of the red iron bridge , the road and footpaths of which were closed after the opening. The project and construction management were at Robert Maillart's engineering firm, while Losinger was entrusted with the execution. The start of construction is dated February 1928. The engineers Eugen Losinger and Simon Mann supervised the construction. The Lorraine Bridge was officially opened on May 17, 1930. The actual construction costs amounted to 2,563,000 Swiss francs . 293,000 Swiss francs still had to be invested in the access road and in other surrounding work. The Lorraine Bridge resembles the older Nydegg Bridge with its closed side walls . A bridge with an open roadway was undesirable as it was perceived as uneasy in the cityscape. The arch bridge is 178 m long, 18 m wide and the roadway is 37.5 m above the water. It consists of thin longitudinal and transverse walls made of reinforced concrete , at that time still called reinforced concrete, which support the deck slab, standing on the vault . Sufficient space was left between the apex of the arch and the deck for an accessible duct.

The elliptical main arch with a clear width of 82.0 m and a stitch of 31.0 m was built from unreinforced concrete boxes according to a design by Robert Maillart . They were prefabricated next to the bridge and then lifted in pairs with a cable crane to their place on the falsework . Initially only one row was laid in the middle of the falsework, which could then support itself and relieve the falsework accordingly. The blocks formed a toothing into which the next row of blocks could intervene like a zipper. The blocks are filled with concrete only where the vault becomes thicker.

The outer walls were roughened using a process that would be called exposed aggregate concrete today . The roadway originally consisted of a weakly reinforced concrete that was placed with a small paver . Only the pavement slabs and the parapets were made of natural stone.

Nesting opportunities for Alpine swifts have been set up at the bridge .

At the southern bridgehead are two sculptures made of shell limestone, designed by the artist Paul Kunz . At the end of the 1940s, a broken pillar led to a twenty meter long and seven meter wide collapse of the street and the sidewalk. Four pillars buckled and a fifth remained crooked. The trigger was construction work on a new greenhouse in the Botanical Garden, which is located directly below the Lorraine Bridge. The pillar foundations were almost undermined due to excavation work .

New traffic routing

Current traffic planning provides for the cycle lane to be widened to 3 meters out of town and, in return, to remove one lane . In addition, the general maximum speed between Lorrainestrasse and Hirschengraben is to be reduced to 30 km / h.

Web links

Commons : Lorraine Bridge  - collection of images, videos and audio files

Individual evidence

  1. ↑ More safety for bikes on the Lorraine Bridge. In: bern.ch. Bern City Council , September 20, 2018, accessed on February 2, 2019 .
  2. ↑ 3 million for Tempo 30 on the Lorraine Bridge. In: derbund.ch. Der Bund , February 1, 2019, accessed on February 2, 2019 .

Coordinates: 46 ° 57 '10.5 "  N , 7 ° 26' 35.7"  E ; CH1903:  600351  /  200205