Mythical Bridges of South-East Switzerland Study trip after IABSE Conference Genève. Saturday, September 26, 2015

Tamina Salginatobel

Sunnital

Landwasser, Filisur

Traversina Valtschiel

Tamins

Chur

Davos

Bad Ragaz

Bad Ragaz

Tamina bridge – Photo montage

28 March 2015 - Arch closure

Tamina - Largest arch bridge in Switzerland Total length 417 m, Span 250 m (Sandö span 264 m) September 26, 2015

Salginatobel, Robert Maillart 1930 Length 130 m, Span 90 m

Robert Maillart (1872 –1940) Born in Bern. Civil Engineer, ETH, Zürich, 1894 Built bridges and moved in 2011 to Russia. His wife died during the Revolution 1917 and he returned to Switzerland with three children. He started to use reinforced concrete and introduced three-hinged arches: The deck and the arch ribs are combined to an integrated stiff structure of very thin reinforced concrete. He won the competition for the Salginatobel bridge due to its low cost.

Total length 132,2 m Arch span 90,4 m Arch rise 13,0 m

Built 1929/30 with wheel- barrowed hand-stamped concrete; arch deck in 40 h Restorated 1997/98

Cows are brought down from sommer season in the mountains to winter season in the valley

Christian Menn (March 3, 1927 - ) Born in Meihringen (outside Bern) Civil Engineer, ETH, Zürich 1950 PhD 1956 Worked in Paris and Bern. Started own consulting company 1957 Based his design on aesthetics and economy and used pre-stressed concrete and cable-stayed bridges. Professor ETH, Zürich, 1971-92

Ganter Bridge, 1980, 678 m Simplon Pass, Valais

Sunniberg, 2001 Designed by Christian Menn

This cable-stayed beam bridge, with low pylons and a stiff deck prestressed by the cables, is sometimes called extradosed (from French extradossé meaning the exterior curve of an arch)

It is an integral bridge without end-bearings or joints. The deformations due to temperature are taken by radial movements, so the piers have to be flexible in the transverse direction. At the bridge ends forces of 9.5 MN in SLS are taken by friction.

Visit after Seminar at EMPA 2007-09-13

Landwasserviaduct, Construction, September 1902

Landwasserviadukt, 1902, 136 m

6 arches with 20m span

Repair 2009 1. New concrete trough 2. Repair of stone work 3-6. New railing, ballast, sleepers and drainage

Visit 2015-09-26 L Elfgren, M Kajio, S Kusuhara, M Valenzuela, K Baumann (Rail Mgr), D Yin, M Cowi, K Schellenberg (Road Bridge Mgr), R Wang, X Shan & L Lyum Structural Engineering, Vol 25, No 4, Nov 2015, pp 381-388 & 482

Traversina Bridge on Via Spluga - a classic 65 km hiking route from Thusis in Switzerland to Chiavenna in Italy

Traversina Steps, built 2005 Span 56 m, Height difference 22 m

Valtschiel, Donat 1924, Span 43.2 m Robert Maillart’s largest bridge without hinge at the arch center. Repaired in 2013 And turned into a pedestrian bridge.

Rhine bridge, Tamins, 1962, Span 100 m Designed by Christian Menn.

Concluding remarks from Study visit and IABSE Conference

• From stone and hand-stamped concrete to cable-stayed high strength prestressed concrete bridges in 100 years.

• Longer spans are built but arches are still competitive when esthetics is considered

• Increased interest in Building Information Methods (BIM), Maintenance/repair strategies and Life Cycle Assessment Methods

Salginatobel Robert Maillart 1930 Length 130 m, Span 90 m

Thank you for your kind attention