Defects of reinforced concrete chimneys in modern operating conditions

Introduction. The paper is devoted to the analysis of the occurrence of the defects on reinforced concrete chimney shafts under current operating conditions. The history of the construction of reinforced concrete chimneys was studied. This paper uses generally accepted survey and analytical research methods. Analytical work was carried out on current methods for eliminating defects in reinforced concrete shafts and a conclusion was made on the ineffectiveness of these solutions.Materials and methods. Inspections of reinforced concrete chimneys built in 1950–1980 were carried out, including the study of design features and construction methods, analysis of operating conditions, visual inspection, as well as inspection of building structures using destructive and non-destructive testing methods. An analysis was carried out to identify the relationships between the design solutions of the reinforced concrete shaft and the current loads from the connected devices to the gas outlet shaft, affecting the internal and, as a consequence, the outer shell of reinforced concrete pipes, in connection with the transition to another type of fuel, which does not correspond to the chimney according to the project. An analysis of the occurrence of defects and modern methods for eliminating them were carried out.Results. It was established during the survey that with the occurrence of defects formed from the transition from solid to gaseous fuel, the load-bearing capacity of reinforced concrete chimneys is sharply reduced, which leads to the failure of structures. Modern methods of defect elimination cause greater destruction in terms of area, as they temporarily eliminate only the consequences, but do not eliminate the causes of defects in reinforced concrete chimneys. In this connection, there is a danger to the operation of technical devices connected to the chimneys, to the buildings in close proximity to the structures, as well as a danger to the life of the operating personnel.Conclusions. The results obtained allow us to reasonably speak about the ineffectiveness of modern methods of eliminating defects, which in turn has only a short-term effect and contributes to great destruction, leading structures to an emergency condition.

reinforced concrete chimneys, defects, gas exhaust shaft, concrete, reinforcement, condensate, leaching of free lime, bearing capacity, residual life