“With regard to the information obtained, we state that the condition of the frame and arch part of the Libeň Group of Bridges is in a very bad construction-technical condition and it is necessary to take immediate action. It is evident that over the past fifteen years there has been an obvious and rapid deterioration of the situation,” experts wrote at the time in a document ordered by TRA, as stated in this article.
Analysis of the Libeň Bridge condition by the Klokner Institute of the CTU
The study was created based on the request of the Prague councilors at the end of November 2018 and dealt with variants of the sensitive reconstruction. The authors were supposed to come up with a proposed structural stability solution and also, for example, compare the lifespan of the bridge after reconstruction with the design lifespan of a new bridge.
What was the plan?
- Excavation and replacement of backfill of vaults, including repair of waterproofing,
- Reconstruction of the spread concrete slab under the road,
- Reinforcement of the vaults above the concrete slab.
- Sealing and strengthening of existing foundations and pillars to limit water migration
Smooth traffic cannot be ensured during the reconstruction
The team from the Klokner Institute headed by the director prof. Ing. Jiří Kolísko, Ph.D. considers the variants chosen to be the compromise of economy, construction time, achieving load capacity according to the currently valid standards of durability, and residual life.
“This variant will enable two-way operation of trams, freight transport (32 tons) as well as utility network transfer to the necessary extent. At the same time, original materials and structural elements of the bridge will be preserved to the maximum extent possible,” wrote the authors in the study in this article.
How long will it take to repair the bridge?
Another article speaks about the schedule for the repair of the Libeň Bridge according to an analysis by the experts from the Klokner Institute. Most sources estimate the duration of the reconstruction at two years. “In all variants, it is not possible to maintain the operation of individual car traffic, urban public transport (trams, or alternative bus transport) and the movement of pedestrians and cyclists on the bridge,” states the study on traffic measures during the repair.
Prague also has to decide where to transfer the utility networks, which are led in the bridge, during the repair works. Solutions include the construction of a temporary bridge or leading the utility networks on the guardrail.