The Libeň Bridge does not need to be demolished, writes a Swiss professor

Prague – The Prague Libeň Bridge does not need to be demolished and should be repaired and preserved. The bridge has high architectural and historical value. This is stated in the opposing report by Swiss professor Eugen Brühwiler from the Swiss Federal Institute of Technology (EPFL) in Lausanne. The report was created as a counter-assessment of the bridge repair proposal from the Klokner Institute at Czech Technical University (CTU). The document is available to ČTK.

The Klokner Institute recommended four variants to the city, from which Prague selected the repair variant that involves strengthening the existing structure instead of replacing it. This is the second cheapest of the four proposed options. The bridge, built in 1928, is in poor condition and has never been repaired.

The Klokner Institute's proposal was recently criticized by the Czech Chamber of Authorized Engineers and Technicians Active in Construction (ČKAIT), which claimed that the document was not scientifically opposed and that the institute lacks experience in bridge design. "I wanted to verify whether the Klokner Institute's proposal is flawed due to the opposition from part of the professional public. I no longer have anyone to assign the opposition to, so I had the document translated and contacted a leading world technical university. Professor Brühwiler's conclusions refute the objections," said Adam Scheinherr, the deputy mayor (Prague Sobě), to ČTK.

The expert report from the Klokner Institute proposed four variants. The city council selected option number two, which involves strengthening rather than replacing the existing structure of the bridge over the Vltava River. The repair is expected to last 32 months and take place from September 2022 to April 2025, at a cost of 477 million CZK.

The Swiss professor stated in the report that option number two meets all requirements. The bridge will meet the demands for load from traffic and will also prevent water from entering the structure, which is the biggest problem of the bridge. He labeled options three and four as too invasive, and the first as technologically insufficient.

At the same time, he recommended the city to consider some modifications. For example, the new reinforcement and slab that will be on the bridge do not need to be 100 millimeters wide, but a 60-millimeter slab is sufficient. According to him, the new slab also does not need to be treated with special waterproof materials, as it is inherently waterproof, thus preventing water from penetrating the bridge. "These are considerations to take into account; after all, the Klokner Institute's report is an ideological intention, not a reconstruction project. However, Professor Brühwiler is not only a theorist but also a practitioner with enormous experience, so we will address the proposals," said Scheinherr.

The Libeň Bridge, built in 1928, is in critical condition and has never been completely repaired since its construction. Last year, it had to be temporarily closed to vehicles and public transport due to its emergency condition. The previous leadership of Prague planned to demolish the bridge and replace it with a new structure. This decision involved a council committee that included members of the ČKAIT. However, the current leadership of the city decided on repair after the elections.