Bryngeån the first bridge in the world equipped with dampers to lower train-induced vibrations

– We have equipped the first bridge worldwide with dampers to lower vibrations from passing trains, says the professor at KTH Raid Karoumi.

He is the task leader for WP5 in KTH, and he is speaking about the installed dampers on the bridge at Bryngån, Sweden.

Raid Karoumi has been involved in In2Track since its beginning. Today he is the task leader of WP5 and the 7-8 people working with the project in the bridge division at KTH in Sweden.

They work with mainly three subtasks in T5.5. At Bryngeån in Sweden, close to Örnsköldsvik, they have installed 4 dampers in a railway bridge.

– I would say that this is a continuation from In2Track2. In 2 we developed the dampers and now in In2Track3 we have installed them permanently, says Raid Karoumi.

With the dampers the bridge will be less susceptible to vibrations from passing freight trains and passenger trains at high speed.

– Actually, this is the first bridge in the world equipped with these kind of dampers, says Raid Karoumi.

The win with the dampers on the bridge is that it will be possible to let future high speed trains (over 250 km/hour) to pass the bridge without introducing harmful vibrations to the bridge or to the trains.

The bridge across Bryngeån

– So there are many benefits with this. We can let the train pass without having them to lower the speed, the professor explains.

This way it will be possible to use the existing lines with the existing bridges without having to rebuild them.

– The major contribution with this project is that it will be possible for future trains to pass these older bridges at high speed. There will be no need to rebuild, at least from this perspective. It will save resources, money and time for the society, Raid Karoumi says.

Visual presentation of work done at Bryngeån

The second subtask that the team at KTH is working on is on developing recommendations for dynamic analysis of bridges for high speed trains. For this more than 30 railway bridges have been dynamically tested in Sweden and in Portugal.

The third subtask will develop new design criteria and new high speed train models for the next generation of European bridge design codes.

– We build bridges that will last at least 120 years. So we have to consider possible future train geometries, loads and speeds that will come in 30, 50, or more years, Raid Karoumi says.

The work is mainly a cooperation between KTH in Sweden and the University of Porto in Portugal.

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