Ganter Bridge is a multi-span reinforced-concrete

road bridge A bridge is a structure built to Span (engineering), span a physical obstacle (such as a body of water, valley, road, or railway) without blocking the path underneath. It is constructed for the purpose of providing passage over the obstacle, whi ...

that is the second longest spanning bridge in

Switzerland Switzerland, officially the Swiss Confederation, is a landlocked country located in west-central Europe. It is bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. Switzerland ...

after

Poya Bridge Poya Bridge () is a cable-stayed bridge in Fribourg, Switzerland. The bridge is in overall length with a main span over the Saane/Sarine, Sarine River, which is the longest main span in Switzerland. The bridge was built to remove traffic from the ...

. It spans the Ganter River valley and is located along the

Simplon Pass The Simplon Pass (; ; ; ; ; ) is a high mountain pass between the Pennine Alps and the Lepontine Alps in Switzerland. It connects Brig, Switzerland, Brig in the canton of Valais with Domodossola in Piedmont (Italy). The pass itself and the villag ...

road about south of

Brig A brig is a type of sailing vessel defined by its rig: two masts which are both square rig, square-rigged. Brigs originated in the second half of the 18th century and were a common type of smaller merchant vessel or warship from then until the l ...

in the canton of

Valais Valais ( , ; ), more formally, the Canton of Valais or Wallis, is one of the cantons of Switzerland, 26 cantons forming the Switzerland, Swiss Confederation. It is composed of thirteen districts and its capital and largest city is Sion, Switzer ...

, Switzerland.Billington, 1983, p.260 It was designed by renowned Swiss

civil engineer A civil engineer is a person who practices civil engineering – the application of planning, designing, constructing, maintaining, and operating infrastructure while protecting the public and environmental health, as well as improving existing i ...

Christian Menn Christian Menn (March 3, 1927 – July 16, 2018) was a renowned Swiss civil engineer and bridge designer. He was involved in the construction of around 100 bridges worldwide, but the focus of his work was in eastern Switzerland, especially in can ...

and completed in 1980. It is notable for its innovative design and its stylish geometric profile in its spectacular Alpine setting.

Design

The bridge's form consists of an S-curve roadway, high above the Ganter River and at about above sea level, supported by two main towers and five smaller piers. They sustain a total of eight spans with lengths of, from north to south, respectively: , , , , , , , and . The main and longest span between the two towers, P3 and P4, is straight, while most of the remaining spans lie along curves with a radius of . The overall length is with a main span of , and a maximum tower height of . Its innovative design combines elements of a

cable-stayed bridge A cable-stayed bridge has one or more ''towers'' (or ''pylons''), from which wire rope, cables support the bridge deck. A distinctive feature are the cables or wikt:stay#Etymology 3, stays, which run directly from the tower to the deck, norm ...

and a

prestressed Prestressed concrete is a form of concrete used in construction. It is substantially prestressed ( compressed) during production, in a manner that strengthens it against tensile forces which will exist when in service. Post-tensioned concreted is ...

cantilever A cantilever is a rigid structural element that extends horizontally and is unsupported at one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a cantilev ...

hollow-box

girder bridge A girder bridge is a bridge that uses girders as the means of supporting its deck. The two most common types of modern steel girder bridges are plate and box. The term "girder" is often used interchangeably with "beam" in reference to bridge d ...

, which has become to be referred to as an

extradosed bridge An extradosed bridge employs a structure that combines the main elements of both a prestressed box girder bridge and a cable-stayed bridge. The name comes from the word ''wikt:extrados, extrados'', the exterior or upper curve of an arch, and refe ...

. The Ganter Bridge is the first of its type to use triangular concrete walls above the roadway to encase the prestressed cable-stays into sails, which protects the cables from corrosion and gives the bridge a distinctive stylish geometric appearance. From some drivers' view, these triangular concrete walls plus the one across the top of the towers made the main span feel too much like a tunnel entrance. Whatever its pros and cons, the innovative and unique Ganter Bridge is one of Switzerland's ground-breaking bridges. In the words of David P. Billington: ''“Ganter bridge ... represents one of those rare events where a new form arises”.''

Construction

Construction began in 1976. The locations of the piers were based on geological conditions as well as symmetry and uniformity of span lengths. The shaft for pier P4 was approximately 40m deep. The south valley side was susceptible to creep movement, so the feet of the south valley piers P4 to P7 were mounted on pot bearings and regularly monitored. After the piers were complete, the balanced free cantilever construction method was employed. By autumn 1979, the entire substructure and approximately 60% of superstructure were complete. By December 1980 the construction was completed on schedule. Between 2006 and 2008 the Ganter Bridge was given a complete rehabilitation as the piers on the south side of the bridge had shifted 105mm southward. Measures were taken to address further movement of the south side piers.

Bibliography

* Billington, David P. ''The Tower and the Bridge''. Princeton University Press, Princeton, USA, 1983. * Billington, David P. ''The Art of Structural Design: A Swiss Legacy.''

Princeton University Art Museum The Princeton University Art Museum (PUAM) is the Princeton University gallery of art, located in Princeton, New Jersey. With a collecting history that began in 1755, the museum was formally established in 1882, and now houses over 117,000 work ...

. Princeton, USA, 2003. .

References

External links

* {{Authority control Extradosed bridges in Switzerland Road bridges in Switzerland Bridges completed in 1980 Cable-stayed bridges in Switzerland 20th-century architecture in Switzerland