PHOTO: The first part of the Old Town Weir is like from the 13th century. There are four sections left
Metrostav’s builders demolished the original structure and replaced it with a new oak grate anchored to wooden piles and filled with granite slabs. They are now preparing the reconstruction of the second section, using a temporary fence to secure the sump to ensure a dry space for further work.
By the end of the year, they want to catch up with the concreting of the foundation slab, so Prague can look forward to other ship concreting, which it experienced this year. Eventually, the work will be completed and resumed in the spring of next year.
“When taking over the first section, the investor was satisfied and I believe that the builder of the original weir from the 13th century would have the same attitude. We use the best materials available in our country – 160-year-old oaks and quality granite stone from block mining. And that it’s some material! Only the total length of wooden beams for a complete grate structure exceeds two kilometers. Just to give you an idea: If we stacked the beams on Charles Bridge, they would create four continuous rows, “said Daniel Boďa, project manager at Metrostav, which is reconstructing the Old Town Weir.
His team will now repeat the procedures they have tried once. They demolish the original concrete filling, dismantle the wooden grate and modify the wooden piles, on which they will then anchor the new grate. After the foundation concrete is built, they install the reinforcement of the foundation slab and pour it with concrete similarly to the foundation slab of a family house. Concreting will again bring an unusual spectacle with a concrete mixer on a press boat. The builders will once again use one of Metrostav’s river concrete plants, which are the only ones available near the city center.
Builders must ensure that the concrete does not harden over the long haul. “In this case, we had to use concrete with a set retarder to make the mixture survive. All the sand and aggregates used for this concrete also traveled to Prague on the Vltava and did not burden the roads, “said Jakub Šimáček, director of TBG Metrostav, who runs two river concrete plants on Rohan Island and Liben near Troja Bridge.
The sloping weir more than 320 meters long lies between Sova’s mills and Novotný lávka. It dates from the 13th century as a Prague-type structure was a model for other constructions in riverbeds in the wider area. In the capital, it is the only one that has retained its original shape, although it has undergone many minor repairs during its existence.
The project will end in 2024 and construction work on site will always be limited to the spring to autumn period. The construction is being built for the Vltava River Basin investor by the construction company Metrostav. Investment costs exceed 112 million crowns.