Vol. 26, Number 1, 2020

Anatoly Orzhekhovsky
Analysis of Reliability Parameters of Structures of Frame-Cantilever Coverings over Stadium Stands
Donbas National Academy of Civil Engineering and Architecture
Abstract. The article discusses stationary frame-cantilever over the stadium stands. Namely, the influence of stochastic variables such as deviations in the geometric characteristics of rolled metal, snow load, subsidence of the base and strength properties of steel on the reliability of the structure. The technique of a simplified approach to calculating the reliability characteristics of a system based on an analysis of the reliability characteristics of the group of the most critical structural elements is considered. The most rational method for calculating the probability of structural failure has been determined. The main parameters affecting the reliability of the system, and methods for taking them into account when determining the reliability characteristics, are substantiated. An algorithm for determining the group of the most critical structural elements and analysis of the survivability of the structure is given. An algorithm is proposed for the numerical determination of the system reliability characteristics based on the finite element method. It has been carried out the analysis of reliability of bearing structures covering over the stands, using variable parameters in the form of departure the console, step frames, angle coverage to the horizon. The analysis was carried out taking into account both separately acting factors, and with joint accounting. For a numerical experiment, the above algorithms are implemented in the MATLAB programming language.
Keywords: building construction, frame and cantilever of the roof above the stands of the stadiums, reliability, stochastic value.

Anatoly Yugov, Sergey Titkov
The Study of Temperature Fields Arising from the Operation of a Tower Metal Cooling Tower in the Winter
Donbas National Academy of Civil Engineering and Architecture
Abstract. The article presents a study of the temperature fields that arise during the operation of a hyperbolic metal tower-cooling tower in winter. Control measurements of temperature fields by means of a thermal imager were made, thermograms of the distribution of temperature fields both in height and around the circumference of the exhaust tower, arising under various weather conditions, were determined. In addition, measurements were taken of the temperature of the basin of the tower and the air temperature at the neck of the tower of a metal tower. The analysis of the results of field studies of temperature fields under various weather conditions is carried out. This work was carried out in order to determine the actual temperature fields for subsequent verification of experimental data obtained in the laboratory using the thermographic method of research by recreating the technological and weather conditions of operation on a specially designed stand that evaluates the quantitative indicator of technological ice and its distribution on the surface of the exhaust tower.
Keywords: metal tower cooling tower, temperature fields, verification, exhaust tower, pool, thermogram.

Volodymyr Mushchanov, Maxim Tcepliaev, Anna Zubenko
Clarification of Normative Expressions for Determining Annular Critical Stresses of Buckling under the Influence of Wind Load
Donbas National Academy of Civil Engineering and Architecture
Abstract. This article is a logical continuation of the study of the rational arrangement of stiffness rings on the cylindrical walls of vertical tanks. In particular, the problem of taking into account the actual distribution of wind pressure on the cylindrical wall of the tank using the finite element method is considered. This allowed us to dertemine the reserves of the bearing capacity of the shell in comparison with the standard values of critical stresses. The reserves are provided due to reduced critical stresses, which give analytical expressions in connection with the reduction of the shape of the wind flow to uniform ring compression. Using the improved methodology for calculating the safety factor, it became possible to determine the coefficients of its increment for a different number of stiffness rings. The obtained refinements allow us to enter coefficients to the normative expressions that determine the values of the ring critical loads of stability loss, through which the rational step of the reinforcing rings of stiffness is assigned. Cases of the shell with ideal geometry and in the case of a defect in the form of the angularity of the vertical weld are considered.
Keywords: vertical cylindrical tank, wind load, stress, finite element method, cylindrical shell, local imperfections.

Alexandr Mushchanov
Optimal Design Solutions for Structural Coatings on Rectangular Non-Standard Layouts
Donbas National Academy of Civil Engineering and Architecture
Abstract. The article considers approaches to optimizing structural coatings on non-standard layouts. The target function is the specific metal content of the coating (G), and the optimized indicators are the relative height of the coating (h/l) and the relative bending boom (f/l). Thus, the optimization process can take place both in one indicator (h / l) and in two at once (h / l) and (f / l). Based on the obtained results, an array of data for regression analysis was generated, performed using the built-in LINEST function in Microsoft EXCEL, which allowed us to express 8 resulting formulas (4 of which are optimization for one indicator and 4 for two indicators), which allow variable design parameters (q – design load and a / b – aspect ratio) calculate the optimal design parameters.
Keywords: structural coating, optimization, multiple linear regression, metal consumption, matlab, Microsoft EXCEL.