THE INFLUENCE OF THE AGGRESSIVE ENVIRONMENT ON THE TIME INTERVALS OF THE STRUCTURAL SURVEY AND THE TIME OF THEIR OPERATION

Abstract

The article considers the problem of determining the required periodicity of surveys (inter<
vals between surveys) to ensure the life cycle of the structures of the ammonia fertilizers production
industrial facilities, which are significantly affected by the aggressive environment.
The analysis of scientific researches and building norms on a problem of definition of terms of operati<
on of buildings and constructions exposed to long action of the aggressive environment and periodicity
of their survey are considered. Difficulties of consideration of many interconnected and mutually influ<
encing factors of aggressive influence of the environment, specific features of a stress<strain state and
the acquired defects of structural elements subjected to long operation cause complexity of development
of deterministic methods of forecasting of terms of operation, periods between surveys, and, therefore,
reliable prediction of the life cycle of structures of this type.
A technique for predicting the periodicity of the necessary surveys of the condition of such structures
and operation periods has been developed. The developed technique is based on generalizations made
by the authors on the basis of the performed statistical analysis of: a) materials of surveys of bearing
reinforced concrete structure of the ammonium nitrate tower K.631G PJSC "Azot" (Cherkasy), conduc<
ted by 7 specialized organizations during its 45<year operation (in aggressive influence conditions); b)
the results of surveys of that tower performed by the authors in 2018<2019.
The characteristic interval of periodicity of surveys (according to 95% reliability) is statistically sub<
stantiated. Based on the analysis, new definitions are proposed: the average and limit intervals of sur<
vey with the number of defects, respectively, 50% and 95%, acquired by structural elements.
On the basis of the analysis carried out for the considered construction with application of the develo<
ped approach, the necessary intervals of surveys are statistically substantiated. The developed metho<
dology and the obtained results are expected to be used to calculate the statistically substantiated sur<
veys interval of reinforced concrete bearing tower<type structures of mineral fertilizers production
enterprises and will extend the life cycle of structures of this type in aggressive environments.