New Tüfi footbridge made from regional beech wood
04.11.2020
The Tüfi-Steg pedestrian and bicycle bridge in Adliswil is getting on in years. Analyses showed that replacing the bridge is almost as expensive as a costly renovation. Today, the new bridge - with beech wood from the surrounding forests - was installed over the Sihl.
New Tüfi bridge made of beech wood - a pioneering project
The Tüfi bridge is the
first bridge made entirely of beech wood. Wood construction pioneer Ernst Gehri used the hardwood for bridges
decades ago for bridges. For the road bridge
in Eggiwil, for example, the suspension posts and cross beams are made of beech glulam.
glued laminated timber. In each case, it was combined with the coniferous
used in the construction of bridges.
Assembly of the new bridge
The beech - mother of the forest
In Switzerland, every
every fifth tree is a beech. It is therefore one of the most
tree species in Switzerland. Despite its good structural properties, beech wood is
properties, beech wood is mainly used as energy wood. In the building industry there are
are still few and far between. The federal government wants to change that and is financing
and is funding research projects to increase the use of beech wood.
beech utilization. Timbatec supports the use of indigenous beech in the building industry
- also in the outdoor area. The balconies on Saumackerstrasse in Zurich or the
Buchholz" playground in Witikon are good examples. For the Tüfi footbridge
beech has also proved to be the best solution.
The construction
The new bridge is
a beechwood bridge structure. It crosses the Sihl River with a span of 45 meters. The inclined struts made of solid
beech wood are only loaded in compression. The vertical steel tie rods
absorb the tensile forces. The steel parts in the nodes allow a very high degree of prefabrication of the bridge and rapid assembly on site. The wood for the bridge was felled by foresters last
winter in the surrounding forests. Holztechnik Burch AG in Sarnen manufactured the new
the new Tüfi footbridge from it according to Timbatec's plans and calculations.
Pressure impregnation
Beech can be used outdoors if it is
Beech can be used if it is pressure impregnated. It is important that
the pressure impregnation penetrates deep into the wood. Only in this way can the wood be
protected in the long term. The weathering of the components will
small cracks will inevitably form. They must not reach deeper into the wood than
the impregnation. The Willisau impregnation plant
pressure impregnation ensures the durability of the Tüfi footbridge,
The wood was cut by Konrad Keller AG. Calculations by KBOB
show that pressure-impregnated timber components are very environmentally friendly.
