Tower in Reuss River Delta near Seedorf, Switzerland

Customer Project

Structural Engineering Timber Structural Analysis
Pirmin Jung Ingenieure für Holzbau AG
Rain, Switzerland

Civil Engineer
Projekta AG
Altdorf, Switzerland
Construction Holzbauer Gebrüder Bissig Holzbau GmbH
Altdorf, Switzerland
Architect Gion A. Caminada Arch. BSA/SA Cons
Vrin, Switzerland
Investor Canton Uri
Committee for the Reuss river delta
Altdorf, Switzerland

The bird watching tower in the Reuss river delta is an exceptional look-out construction in the Urner Alps. Its striking primary framework consists of 48 log wood columns standing in an inclined position. From four viewing platforms, people seeking relaxation enjoy the wonderful view into the river delta, and ornithologists can watch nesting birds.

The tower with a height of 11.5 m was designed by the Swiss architect Gion A. Caminada. The structural analysis was performed by Pirmin Jung Engineers, the customer of Dlubal Software.

Structural Analysis and Construction

The round columns consisting of silver fir timber were chopped down, treated and prepared in the immediate surroundings of the construction site.

At the base, they have a diameter of approximately 240 mm and are tapered towards the roof that they bear as much as the viewing platform. The platform consists of planks that are 80 mm thick, cantilevering where the four lookout baskets are installed. It is directly attached to the log wood columns by means of brackets. The roof rafters are supported by the center post and the external columns.

Moreover, a steel ring hangs down the roof structure upon which the internal side of the platform floor lies and from which the spiral stairway is suspended.

All connections are built in such a way that they can be easily replaced after the service life has expired and without any influence on the total structure.


In addition to wind loads, the tower must also be able to absorb vibrations from live load. As additional bracings or similar stiffening elements for horizontal structural stabilization did not come into consideration because of architectural reasons, the columns received a partial restraint to the steel ring in the roof. In this way, a kind of spatially effective frame was formed.

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