“We developed a special concrete mix for all the structural blocks in cooperation with the Klokner Institute based on a request from the client, the public-sector river manager Povodí Vltavy. The secret formula is designed to make the concrete last 150 freeze cycles instead of the standard 90, while reducing the amount of hydration heat. It’s great that we can use the mobile concrete batching plant we set up here for the needs of the construction site. At the moment, we are as close as possible to the dam with the spillway and after the last blocks are completed, the main focus will be on inlet structure SO01,” said Tomáš Beržinský, a representative of the contractor Metrostav.
His team has had to deal with adverse geology over the past year and this has had a major impact on the inlet structure. Due to the very diverse rock environment, Metrostav’s construction workers first had to create a remedial screen. Thanks to precise cooperation from all project participants, they managed to seal the construction pit in mid-April so that water management workers could raise the level in the reservoir and start the sailing season using a lift for sports vessels.
“We are literally fighting the rock because every square metre has different characteristics, from hard rock to a heavily weathered and tectonically disturbed surface. Due to these conditions, the design of this section’s foundations on the site had to be modified. We have now hopefully identified and solved the main problems, which allows us to start the first concrete pouring inside the pit,” added Beržinský.
How the giant project at Orlík is currently progressing is shown by the figures representing the movement of masses and volumes of material used. Metrostav’s construction workers must quarry or blast a total of 180,000 cubic metres of rock. When blasting, each blasted block must be covered with mats to prevent aggregate from flying off, and this also protects the dam’s surroundings. This must be done block by block. The total volume of concrete to be used should reach 65,000 cubic metres and the weight of the steel reinforcement will be thousands of tonnes.
The construction of the new emergency spillway at Orlík Dam is a response to the devastating flood of 2002, the application of new technical standards and the culmination of more than ten years of preparation of a complicated project. The aim of the CZK 1.78 billion investment by Povodí Vltavy is to increase the flood flow capacity from the current 3,550 to 5,300 cubic metres per second, which corresponds to the worst flood in 10,000 years. The spillway is being built outside the dam’s main body and will have three spillway fields with massive steel segments. Any extreme flooding will then be diverted under the dam by a concrete chute.
Radim Mana
Metrostav Group Spokesman
Metrostav a.s. Koželužská 2450/4 180 00 Prague 8
T: 266 019 715, M: 601 110 376
radim.mana@metrostav.cz
