Six thirty-ton vehicles are testing the condition of the Legion Bridge

Prague - The Prague Technical Road Administration (TSK) has begun load testing on the Legions Bridge. With the help of six thirty-ton trucks and sensors, employees from specialized companies will collect data today and on Tuesday evening, which will be used to create a detailed diagnosis of the monument-protected bridge. It is in poor condition and requires reconstruction, which TSK hopes to start after 2020. Starting today and until next Monday, no traffic is allowed on the bridge.

The load tests represent the third phase of the overall diagnosis of the bridge, which began in the summer. "It is one of the conditions for us to prepare the project documentation for the overall reconstruction," said TSK spokesperson Barbora Lišková. She added that, in addition to the overall condition of the bridge, it is necessary to describe in detail the materials that will need to be used for the reconstruction due to preservation requirements.

The thirty-ton trucks will drive on the bridge not only today but also on Wednesday evening; however, the bridge will be closed until Monday. TSK has utilized the repairs of the tram line, which began today and will last until Monday, just like the diagnostic work.

Under the bridge, workers have placed sensors connected to the structure by wires, which record the movements of the bridge and its response to loading as the trucks pass over it. According to Martin Krejcar from Inset, the loading of the bridge is measured in various ways, for example, by having one vehicle slowly pass during static measurements or placing the heaviest load possible at one point on the bridge. This measures the deflection of the bridge at that point. During dynamic measurements, where loaded vehicles pass at speeds of up to twenty kilometers per hour, the oscillation of the structure is measured.

Today, workers also began drilling depth probes that reach approximately fifteen meters into the bridge's substructure. There will be four in total. In addition, thermal probes and other measuring devices have already been placed on the structure. For diagnostic work under the bridge, a pontoon has been positioned on the river.

After the measurements are completed, specialists from the Klokner Institute at the Czech Technical University will take over the data collected, which they will process into the final diagnosis. According to Lišková, the first preliminary results could be known in a few months, and the final document will be ready by the middle of next year. According to the spokesperson, the costs for similarly extensive diagnostics reach tens of millions of crowns.

Bridge condition issues have been long-term in Prague; last year a footbridge collapsed in Troja. In addition to the Legions Bridge, diagnostics are currently underway for the Hlávka Bridge, which is also in poor condition. Diagnostics for Palacký, Barrandov, and the Cable Bridge on the South Connection is also being prepared. The Libeň Bridge is also in bad shape, having had to be temporarily closed to cars and trams earlier this year. At the end of October, it was also necessary to temporarily close one of the bridges connecting Vltavská and Hlávkův Bridge.