Award-winning Oder river bridge cuts 500 tons of steel with CFRP tension cables

The new cross-border bridge at Küstrin consists of a network arch with a span of 130 meters and 88 carbon hangers. Source | Deutsche Bahn AG/Volker Emersleben

A multi-award-winning infrastructure project, the Oder Bridge near Küstrin, Poland, is supported by a 130-meter-long network arch with prestressed carbon fiber-reinforced polymer (CFRP) tension members developed by Empa spin-off Carbo-link (Fehraltorf, Switzerland) and tested and evaluated by Empa (Dübendorf), the Swiss Federal Laboratories for Materials Science and Technology. Eighty-eight ultra-lightweight, durable CFRP cables stabilize the filigree construction over the Oder River.

The railway bridge over the Oder is a double-track network arch bridge. Although such CFRP cables have already been used on another bridge, this is the first time they have been used worldwide for heavy rail freight traffic; trains can now pass over the structure at speeds of up to 120 kilometers per hour — which required extensive testing and complex approval procedures. The bridge received two awards for its design — the British Bridges International Award and the German Bridge Construction Prize.

According to the jury of the German Bridge Construction Prize, the Küstrin Oder Bridge is not only considered an engineering masterpiece but is also “pioneering in terms of economy and sustainability.” The 88 carbon hangers significantly reduce the weight compared to conventional flat steel hangers due to CFRP’s high tensile strength and optimal fatigue resistance. This opens up new design freedoms, as the airy, transparent appearance of the Oder Bridge demonstrates. In addition, the material savings reduce construction costs and maintenance requirements in the long term.

Hangers made of carbon fiber-reinforced polymer (CFRP) tested at Empa provide strength and sustainability. Source | Empa

Overall, the use of CFRP hangers saved around 500 tons of steel and 1,350 tons of reinforced concrete in the bridge’s overall structure. A sustainability study by Urs Meier, CFRP pioneer and former member of Empa’s Directorate, shows that the composite version saves around 20% CO₂ emissions compared to a steel structure.

According to Lorenz Haspel, the project manager responsible at engineering firm schlaich bergermann partner (sbp, Stuttgart, Germany), the CFRP bridge would not have been possible without Empa. “The innovative CFRP hangers come from the Empa spin-off Carbo-link in Fehraltorf — founded by Andreas Winistörfer, CEO and former Empa doctoral student –—and have now been used for the second time in a network arch bridge,” says Haspel. “We used such carbon [fiber] cables for the first time as highly stressed tension members in a network arch on the city railway bridge in Stuttgart.”

The fatigue tests for the Oder bridge were largely carried out by a team from Empa’s Structural Engineering lab led by Robert Widmann and Dimitri Ott in Empa’s construction hall, confirming the necessary fatigue strength of the CFRP material. Giovanni Terrasi, head of Empa’s Mechanical Systems Engineering lab, also worked with Christian Affolter to prepare the technical report for the bridge. “We have laid the foundation for a new generation of filigree network arch bridges with carbon [fiber] hangers as load-bearing elements,” Terrasi believes.