Design aspects of the concrete chimney at Pocerady, Czech Republic
Noakowski, Breddermann, Hes, Buizer, Jezek, and Sipek
CICIND REPORT Vol. 12, No. 1, 1996
Order No: CR-015
The paper describes two aspects of the design of this 200m tall chimney, built downstream of FGD for the Pocerady Power Station. These aspects were: (a) the considerations leading to the choice of a sectional brickwork liner and (b) the design of the very tall duct openings in the concrete shell.
References are provided for the decision to choose insulated brickwork instead of metal or other types of lining - the paper concentrates on the choice between an independent and a sectional liner. Because of the large duct openings, the lower 33m of brickwork in both cases was laid against and supported by an inner concrete shell. Above this, the sectional liner comprised 6 sections 26m tall, the upper 5 being supported by the shell and the lower section being supported by the internal concrete shell. The independent liner case utilised coated steel reinforcement. The choice of sectional liner was made after an analysis of the pros and cons of the two systems, but mainly because of doubt about the long term integrity of the coated steel reinforcement in the independent liner case. As recent experience has shown this system to be reliable after many years (see Busch/Noakowski's paper in CICIND REPORT Vol. 10, No. 2 Autumn 1994), the author is now of the opinion that an independent liner would be the best solution.
The opening required for the duct entry is 23m tall and is divided into 3 parts by two horizontal strengthening beams. The paper describes the complex system of prestressing and thermal isolation used, together with the associated structural analyses.