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Wildlife Overpass Rynetel, Suhr



It took a long time to convince people: more than 20 years ago, Stefan Zöllig demonstrated that wood is the right choice of construction material for wildlife bridges. Today, the wooden bridge over the N01 highway between Suhr and Hunzenschwil is impressive.

The wooden structure remains visible from below zoom
The wooden structure remains visible from below
Assembly work at night zoom
Assembly work at night
Assembly work during daytime zoom
Assembly work during daytime
Aerial view during assembly zoom
Aerial view during assembly

The Project

Because traffic routes cut through the habitats of wild animals, the Federal Office for the Environment defined wildlife corridors of supraregional importance. The "AG6" corridor connects the Jura region with the Central Plateau and runs between Gränichen and Suhr over the N01 national highway. Here, the new 50-meter-wide arched wooden structure now enables wildlife to cross the highway safely.

During the planning phase, various construction methods were tested and compared with each other. The renewable building material came out best in this comparison - the decisive factors were the better ecological balance and the faster execution.

The Construction

The wildlife overpass is constructed of prefabricated 156 glulam beams. The girders, each weighing two tons, are 17.4meters long, have a cross-section of 24 by 76 centimeters and are mounted on the cast-in-place concrete walls with steel joints.

The girders are made of Swiss spruce boards and an RF adhesive bonded to keep their shape.

The Challenges

Construction projects over traffic routes are always demanding, because for the assembly of the supporting structure. The highway was reduced to two lanes for only 24 nights from 9:30 p.m. to 4 a.m. each night. Furthermore, a lot of pioneering work was done for the planning of this lighthouse project.

Construction Data

- Spans: 2 x 17.4 meters

- Length: 35.6 meters (across the carriageway)

- Width: 54 meters (lengthwise to the carriageway)

- Bridge area: 1'922 m² 

- Construction timber: 850 m³ spruce, origin Switzerland

Construction costs

- 13.9 million Swiss francs

Prestations de Timbatec

- SIA Phase 31 Preliminary project
- SIA Phase 32 Construction project
- SIA Phase 41 Tender and comparison of offers 
- SIA Phase 51 Implementation project
- SIA Phase 52 Design
- SIA Phase 53 Commissioning
- Expert planning fire protection
- Work planning 3D and 2D

Building Owner
Bundesamt für Strassen ASTRA, Filiale Zofingen
4800 Zofingen

Timber Construction
Häring AG
5074 Eiken


Ingenieurgemeinschaft WUEF;

Bänziger Partner AG, 5400 Baden und

Timbatec Holzbauingenieure Schweiz AG, 3012 Bern


Aravia Bau AG

5303 Würenlingen

Supplier glulam

Hüsser Leimbau AG

5620 Bremgarten


Nils Sandmeier

2501 Biel

  • Erste Tiere haben die Wildtierbrücke Rynetel überquert

    First animals have crossed the wildlife bridge Rynetel

    Landanzeiger, Issue No. 4/2022 – The animal bridge over the highway between Suhr and Gränichen, which cost around 13.9 million Swiss francs, was completed last summer. Now animal movement is slowly coming over the bridge. (Report in German)

  • Anerkennung für die WTK Rynetel und das Krokodil

    Recognition for WTK Rynetel and the "Krokodil"

    Themenheft von Hochparterre, Issue Oktober 2021 – We are particularly pleased about the recognition for the Rynetel Wildlife Bridge and "Krokodil" projects. As timber engineers, we were able to play a decisive role in shaping these projects. (Report in German)

  • Freie Bahn für Hase, Hirsch und Reh

    A clear path for hare, deer and roe deer

    Neue Zürcher Zeitung, Issue 09.10.2021 – Wildlife bridges serve traffic safety and the preservation of biodiversity. The concept has long since been perfected, but there are problems with implementation. (Report in German)

  • Erste Wildtierbrücke aus Holz

    First wildlife overpass made of wood

    Initiative Holz, Annual Report 2020 – It took a long time to convince people: More than 20 years ago, Stefan Zöllig demonstrated that wood is the right choice of construction material for wildlife bridges. Today, the Rynetel wooden bridge over the A1 highway is impressive - and more will follow. (Report in German)

  • Die Wildtierbrücke ist fast fertig

    The wildlife bridge is almost ready

    Zofinger Tagblatt, 5. Mai 2021 – Now it is almost finished, the new wildlife bridge over the highway near Neuenkirch. For several nights, the last 45 of a total of 90 huge wooden girders were assembled, causing traffic obstructions. 17.5 meters long, 1.24 meters high, weighing 8 tons, these girders will carry the soil and planting over which the once deer, foxes, deer and small mammals walk. (Report in German)

  • Wildtierüberführung Rynetel

    Wildlife overpass Rynetel

    TEC21, Issue No. 37/2020 - The "national road network" of wildlife gets a new element in Aargau. With its wooden superstructure, the green bridge over the freeway Al is the first of its kind in Switzerland. It will soon make it easier for animals to migrate between the foothills of the Alps and the Black Forest. (Report in german)

  • Der grüne Teppich über der A1

    The green carpet over the highway

    First, Issue No. 04/20 - Rynetel Suhr (AG) wildlife overpass: The arched truss construction on in-situ concrete walls forms both a passageway and habitat for numerous native species of animals above the A1. Underneath it, on the longest freeway in Switzerland, the traffic roars. The green bridge was completed in autumn 2020. It should not remain the only one of its kind.

  • Erste Schweizer Wildtierbrücke aus Holz

    First Swiss wild animal bridge made of wood, Issue No. 11/2020 - Timber construction is certainly suitable for instrumental construction. Over the A1 freeway near Aarau, Switzerland's first wildlife bridge is being built mainly of wood. The required amount of wood has grown back in the Swiss forest within 3 hours and 26 minutes. (Report in german)

  • Wild oben drüber

    The wildlife above

    Schreiner Zeitung, Issue No. 40/2020 – Kurz&Bündig. Switzerland's first wooden bridge for wild animals has been built. Soon, wild boar, hare and co. will be able to safely cross the A1 highway between Hunzenschwil and Suhr in the canton of Aargau. (Report in German)

  • Erste Wildtierbrücke aus Holz über die Autobahn A1

    First wooden wild animal bridge over the A1 motorway

    Der Landanzeiger, Issue No. 39/2020 - Between Suhr and Hunzenschwil the first wooden wild animal bridge in Switzerland is being built. 850 m3 of wood, 22'000 screws, 220'000 nails and 312 metal shoes were used. The arched construction made of Swiss wood will soon enable wild animals to cross the highway safely. The Landanzeiger was present during the site inspection. (Report in german)

  • Brücken statt Barrieren

    Bridges Instead of Barriers

    Pro Natura Magazine 3/2018 - Timber bridges over motorways can make an important contribution to the life and sometimes also the survival of wildlife species. At the same time, they are much easier to build than concrete bridges, the construction of which involves the closure of entire sections of motorway for several weeks. Different crossings made of timber: They can be prefabricated from timber elements and mounted on just two weekends. This is shown by examples from Germany. In Switzerland, Timbatec is currently planning several timber wildlife bridges. The Pro Natura Magazine reports in detail on ten pages about the important crossings for wild animals and also interviewed Timbatec founder Stefan Zöllig, who has been promoting timber bridges for wild animals for a long time. The reason for these crossings: Motorways cut through the Swiss landscape and thus also the natural paths of wild animals. Among other things, these barriers prevent the animals from migrating between their feeding, resting and reproduction sites. The consequences go as far as the local extinction of animal species in these areas. That is why bridges are needed over the motorways over which the wild animals can circulate.

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Timbatec Timber Construction Engineers Switzerland Ltd.

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