With a total generating capacity of approx. 2,900 MW, the Kozienice Power Plant south-east of Warsaw is Poland's second largest coal-fired power plant and consists of 10 generators. In 2014, construction of an 11th generator started that will provide an additional 1,075 MW of energy after its completion.
A part of this huge construction project is a retention facility for fly ash produced in the coal burning process. The fly ash is stored in three identical tanks, each of them providing 20,000 m³ of storage capacity.
Tank walls are 300 mm "thin"
These slender concrete structures have inner diameters of 25.8 m, 48.3 m high chambers and a wall thickness of only 300 mm.
The tank walls were post-tensioned using seven strand "hoop" tendons that were installed in the perimeter and anchored in pilasters. Each "hoop" consists of two half-circle tendons. DSI Construction Poland was awarded the post-tensioning work. The scope included the technical support of the subcontractor during post-tensioning and the supply of approx. 8,400 m of strand tendons with 1,152 MA stressing anchorages. DSI installed, stressed and grouted the strand tendons.
Special challenge: tank height of 65 m
In addition to the tight schedule, the very large height of the 65 m tall tanks represented a challenge: The highest tendons were installed at a height of 62.25 m above ground. Furthermore, due to the fact that the chamber walls were erected using sliding formwork technology, and due to the small amount of storage space, all of the post-tensioning systems had to be supplied to the jobsite just-in-time. Thanks to the minimal space requirements of the strand tendons that were supplied on coils, the pilasters were realized very efficiently.
Also, the robust post-tensioning system ensured an easy installation of the MA Anchorages and trumpets. The accessories – especially the reliable threaded connections between the PE grout caps and the anchor plates – ensured that grouting work proceeded smoothly.