Several members of the Swiss family Grubenmann were famous as joiners and civil engineers in the eighteenth century. The sons were innovators in bridge construction.

Ulrich Grubenmann (1668 - June 27, 1736) lived all his life in Gstalden , Appenzell Ausserrhoden where he fathered three sons:

• Jakob Grubenmann (January 10, 1694 - October 5, 1758), died in Hombrechtikon , Zürich;
• Johannes Grubenmann (June 15, 1707 - June 10, 1771), died in Teufen; and
• Hans Ulrich Grubenmann (March 23, 1709 - January 22, 1783), died in Teufen.

The brothers were village carpenters in Teufen. The principle structures are known to be:

• Crossing of the Rhine at Schaffhausen in two spans of 52 m and 59 m respectively, (Hans Ulrich, 1775);
• A single-span of 73 m at Reichenau, (Johannes);
• Crossing of the Limmat at Wettingen , a 60 m span thought to be the first use of a true arch in a timber bridge, (Hans Ulrich and Johannes, 1758).

None of their bridges has survived, those at Schaffhausen and Wettingen being burnt by the French in the war of 1799, but their designs were influential, making use of novel combinations of arches and trusses.

Bibliography

• de Mechel, Chrétien Plans, coupes et élévations des trois points de bois le plus remarquables de la Suisse
• John Soane and the Wooden Bridges of Switzerland: Architecture and the Culture of Technology from Palladio to Grubenmanns, catalogue of an exhibition at Sir John Soane's Museum, ISBN 8887624240
• Timoshenko, S. P. (1953) History of Strength of Materials, pp182-183, ISBN 0486611876