Empa Innovation in Bridge Construction: Award-Winning Railway Bridge Thanks to Swiss Carbon Cables

A brilliantly white arched network with a span of 130 metres supports the new border bridge near Küstrin. 88 carbon hangers stabilize the delicate structure over the Oder. For the first time worldwide, such tensile elements made of carbon fibre reinforced polymer (CFRP) were used in a railway bridge – developed by the Empa spin-off Carbo-Link and tested as well as evaluated at Empa.

The novel material not only allows for a particularly material-efficient construction method but also significantly reduces CO2 emissions compared to a conventional steel construction. For this pioneering construction, the bridge was twice awarded – with the British 'Bridges International Award' and the German Bridge Construction Award.

Lighter Carbon Instead of Heavy Steel According to the jury of the German Bridge Construction Award, the Küstrin Oder Bridge is not only an engineering masterpiece but also economically and sustainably future-oriented. The 88 carbon hangers significantly reduce the dead weight compared to conventional flat steel hangers, as CFRP offers high tensile strength and better fatigue resistance than steel – all while being significantly lighter.

This opens up new design freedoms, as impressively demonstrated by the airy, transparent appearance of the Oder Bridge. Furthermore, the material savings reduce construction costs and decrease maintenance efforts in the long term.

In total, the use of CFRP hangers saved approximately 500 tonnes of steel and 1350 tonnes of reinforced concrete in the overall load-bearing structure of the bridge. A sustainability study by Urs Meier, a CFRP pioneer and former member of the Empa management, shows: The carbon variant saves around 20 percent of CO2 emissions compared to a steel construction.

High Demands on the Railway Bridge The railway bridge over the Oder is a two-track arch network bridge in composite construction, equipped with pre-stressed CFRP hangers. Although such carbon cables have been used on another bridge, this was the first time they were used worldwide for heavy railway freight traffic. Trains can now pass the structure at speeds of up to 120 kilometres per hour – requiring extensive tests and complex approval processes.

According to Lorenz Haspel, the project manager at the engineering firm schlaich bergermann partner, this carbon bridge would not have been possible without Empa. The novel CFRP hangers are from the Empa spin-off Carbo-Link in Fehraltorf – founded by Andreas Winistörfer, CEO and former Empa doctoral student – and have now been installed for the second time in a network arch bridge.

'We first used such carbon cables as high-stress tensile elements in a network arch at the urban railway bridge in Stuttgart,' says Haspel. The fatigue tests for the Oder Bridge were largely carried out by a team from the Empa 'Structural Engineering' department led by Robert Widmann and Dimitri Ott in the Empa construction hall – confirming the required long-term durability of the novel CFRP material.

Giovanni Terrasi, head of the Empa 'Mechanical Systems Engineering' department, together with Christian Affolter, also prepared the technical report for the now award-winning bridge. 'With this, we have laid the foundation for a new generation of delicate network arch bridges with carbon hangers as supporting elements,' Terrasi is convinced.

Media Contact:
Prof. Dr. Giovanni Terrasi
Mechanical Systems Engineering
Tel. +41 58 765 41 17
giovanni.terrasi@empa.ch