Wildlife transfer Rynetel, Suhr
2021
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 A1 highway between Suhr and Hunzenschwil is impressive.
Facts and images
Construction Data
Involved
Articles
The wooden structure remains visible from below
Assembly work at night
Assembly work during the day
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 corridor "AG6" connects the Jura region with the Central Plateau and runs between Gränichen and Suhr over the A1 national road. Here today, the new 50-meter-wide arched wooden structure allows 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 156 prefabricated glulam arches. The girders, each weighing two tons, are 17.4 meters 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 challenge
Construction projects over traffic routes are always challenging, as the highway was reduced to two lanes from 9:30 p.m. to 4 a.m. each night for just 24 nights to install the structure. 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
- Structural timber: 850 m3 Spruce
- Origin Switzerland
Construction costs
- 13.9 million francs
Services of Timbatec
- SIA Phase 31 Preliminary design
- SIA Phase 32 Construction project
- SIA Phase 41 Tendering and comparison of offers
- SIA Phase 51 Implementation project
- SIA Phase 52 Execution
- SIA Phase 53 Commissioning
- Fire protection planning
Client
Federal Roads Office ASTRA
4800 Zofingen
Timber construction
Häring AG
5074 Eiken
Photography
NILS SANDMEIER
2501 Biel/Bienne
Planning
Ingenieurgemeinschaft WUEF;
Bänziger Partner AG, 5400 Baden and
Timbatec Holzbauingenieure
Master builder
Aravia Bau AG
5303 Würenlingen
Glulam supplier
Hüsser Leimbau AG
5620 Bremgarten
Rynetel wildlife overpass near Suhr
Zuschnitt 92, March 2024 – Wood is the right choice of building material for wildlife bridges. Today, the wooden bridge over the A1 highway between Suhr and Hunzenschwil is impressive. (Report in german)
Building the future: Wildlife Bridge Biberlikopf, Cantonal border Glarus, St. Gallen
Baukader, Issue No. 09/2023 – The A3 highway in the north of the canton of Glarus has cut through the Biberlikopf wildlife corridor for decades. This is now to change. The wildlife overpass will restore the animals' natural migration routes. Planning for this is in full swing. (Report in german)
Modern timber construction revolutionizes the building industry
Fokus Bau & Immobilien, Issue June 23 – Modern timber construction is conquering the building world. All over the world, investors are planning high-rise buildings that will reach heights of over 100 meters. Residential buildings with 300 units are already a reality in Switzerland. The high flight of timber construction is probably far from over. (Report in german)
Meeting climate targets with wood
MODULØR, Issue No. 3/2023 – The motion "Research and innovation of wood as a material for use in infrastructure construction as a decarbonization contribution" was accepted in the Council of States and the National Council. Now it is up to the wood industry and the researching universities to present solutions as to how steel and concrete can be sensibly and expediently replaced by CO₂-storing materials in the future. One possible area of application is wildlife crossings. (Report in german)
Of bridges, towers and an «ice snake»
Holz-Zentralblatt, Issue No. 05/2023 – On the last day of the 26th «International Timber Construction Forum - IHF» in Innsbruck from November 30 to December 2, 2022, the event block «Exposed Engineering Structures» offered a project selection of bridge and tower structures as well as insights into the planning and construction of the free-form roofing for the World Cup luge track in Oberhof. The subject area not only showed a great variety of forms in this special discipline, but also how it was possible to plan the structures economically, sometimes finding novel solutions.
Wildlife bridges under extreme loads
26th International Timber Construction Forum IHF 2022 – The construction of roads, railways, infrastructure, housing estates, industrial and commercial areas In heavily built-up Switzerland, wildlife connectivity is limited by the construction of roads, railways, infrastructures, settlements and industrial and commercial areas. Wildlife habitats are geographically demarcated with insurmountable barriers, suppressing the animals' natural urge to move. Wildlife bridges connect the animals' reservoirs.
Wildlife transfer Rynetel, Suhr
Lignum Holzbulletin 144/2022, Engineering structures –The wildlife overpass near Suhr is the first large timber structure to cross a highway in Switzerland. The arched structure, which connects the forest on both sides of the highway for wildlife, is visible to all motorists. The chosen solution shows that the renewable raw material is also interesting for infrastructure construction. (Report in German and French)
Wooden bridges for the next generation of infrastructure routes
VSS, Special Edition Wooden Bridges, Issue No. 7-8/2022 – Wood as a material and its wide range of products and technologies can be used not only for bridges for low-speed traffic, but also offer the potential for heavy-load traffic. Newly, long-span wooden bridges with a box girder cross-section and prestressing are to be used for heavy goods traffic. For a climate-neutral Switzerland 2050, answers from research and development are needed to show the construction industry new, efficient and climate-neutral solutions. (Report in German and French)Wildlife overpass in wood
VSS, Special Edition Wooden Bridges, Issue No. 7-8/2022 – The motion «Research and innovation of wood as a material for use in infrastructure construction as a decarbonization contribution» was accepted in the Council of States and the National Council. Now it is up to the wood industry and the researching universities to present solutions on how steel and concrete can be replaced by OC₂-storing materials in a sensible and practical way in the future. One possible area of application is wildlife overpasses. Even before the motion was submitted, the Federal Roads Office (FEDRO) had decided to build such structures in wood in Suhr and Neuenkirch. (Report in German and French)
Working model of heavy duty wooden bridge inaugurated
hbs holzBaumarktSchweiz, Issue No. 4/2022 – Will we build large infrastructure structures such as highway bridges from wood in the future? Through the increased use of wood, infrastructure construction could contribute to decarbonization. Heavy-duty bridges with prestressed box girder elements would make large structures such as highway bridges and viaducts possible. A working model of this has been on display in Biel since May 9. (Report in German)
After wildlife overpass comes wooden highway bridge
Holz-Zentralblatt, Issue No. 26/2022 – Infrastructure construction is one of the largest Co₂ emitters in Switzerland. The main cause is the use of reinforced concrete. Through the increased use of wood, infrastructure construction could contribute to decarbonization. Heavy-duty bridges with prestressed wooden box girder elements could also enable large structures such as highway bridges and viaducts. (Report in German)
Highway bridges – made of wood?!
Wir Holzbauer, Issue 5.2022 – For timber engineer Stefan Zöllig, timber construction should continue to gain momentum - carried by research projects such as the heavy load bridge made of wood. His latest project was presented and inaugurated in early May at the fourth International Timber Bridge Conference ICTB on the campus of BFH Biel with a first bridge model. (Report in German)
The CO₂ savings would be great
Bieler Tagblatt, Issue No. 10.05.2022 – Timber construction: Can bridges for heavy traffic also be built from wood? This question is being investigated by a research consortium at Bern University of Applied Science. A ten-meter-long working model was presented yesterday in Biel. (Report in German)
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)
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)
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)
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)
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)
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.
First Swiss wild animal bridge made of wood
Baukader.ch, 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)
