Центральноукраїнський науковий вісник. Технічні науки. Випуск 5. Частина 1. - 2022
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Item Метрологічне забезпечення контролю технічних характеристик будівельних матеріалів і виробів(ЦНТУ, 2022) Пашинський, В. А.; Пашинський, М. В.; Дарієнко, В. В.; Pashynskyi, V.; Pashynskyi, М.; Darienko, V.На основі теорії похибок та методу лінеаризації функцій випадкових величин отримані робочі формули для оцінювання імовірних похибок експериментального визначення середньої густини, вологості, водопоглинання та міцності при стиску будівельних матеріалів на зразках правильної геометричної форми. Отримані формули дозволяють обґрунтовано вибрати засоби вимірювань з урахуванням необхідної точності визначення технічних характеристик. The problem of assessing the possible relative errors of the technical characteristics of building materials when testing samples of the correct geometric shape has been solved. The work is based on the theory of errors and on the method of linearization of functions of random variables. The technical characteristics of the materials are determined by the equations of indirect measurements through the input parameters, directly measured during the tests with known level of accuracy. Linearization of the equations of indirect measurement allowed to obtain dependences for determining the standard and probable relative errors of determining the average density, humidity, water absorption and compressive strength of building materials. Samples of the correct geometric shape of the following types are considered: cube, parallelepiped, circular cylinder. The input values of the obtained formulas are the size and weight of the samples, as well as the destructive force during compression. The accuracy of direct measurement of these values is determined by the values of division of the corresponding measuring instruments. The obtained formulas give possible relative errors of indirect measurements of the analyzed technical characteristics corresponding to the given two-way security level. The use of the obtained formulas allows you to reasonably choose the means for measuring the input parameters that provide the necessary accuracy of the results of determining the technical characteristics with the maximum ease of performing the measurements. The method for assessing the accuracy and the choice of measuring instruments for measuring the size and mass of samples is illustrated by an example of determining the average density of a mortar based on the results of testing cubic samples of different sizes. The results of the study can be used in the experimental determination of the analyzed technical characteristics of building materials of other types, as well as extended to assess the accuracy of other technical characteristics, which are determined by indirect methods.Item Порівняння методів розрахунку плитних фундаментів з урахуванням результатів інженерно-геологічних вишукувань та геодезичних спостережень за процесом просідання(ЦНТУ, 2022) Пашинський, В. А.; Тихий, А. А.; Пашинський, М. В.; Карпушин, С. О.; Яцун, В. В.; Pashynskyi, V.; Tykhyi, A.; Pashynskyi, M.; Karpushyn, S.; Yatsun, V.На прикладі фундаменту під силос зерносховища у вигляді круглої залізобетонної плити діаметром 20,4 м виконане порівняння трьох методів розрахунку осідання суцільних плитних фундаментів. Розрахунки за моделлю плити на пружній основі та за моделлю об'ємних скінченних елементів дали середні значення осідання 2,15 см та 2,4 см, близькі до фактичної величини 1,75 см, отриманої за результатами натурних геодезичних спостережень, що велися з початку будівництва об'єкту. Регламентований чинними нормами проектування розрахунок за методом пошарового підсумовування дав різко завищений результат 13,7 см. Increasing the height of buildings and structures in combination with the development of areas with unfavorable geotechnical conditions cause the use of foundations in the form of solid reinforced concrete slabs. In complex geotechnical conditions and under high loads, the soils can work beyond linear deformation. This necessitates the calculation of the system "building-foundation-soil" based on the assumptions of nonlinear soil mechanics. The issue of designing foundations for cylindrical structures of the agro-industrial complex, in particular granaries, is especially relevant. The task of this study is a comparative analysis of different methods for calculating the subsidence of slab foundations to select a rational model of deformation of the soil. The comparison of calculation methods is carried out on the example of the foundation under the granary with a volume of 8841 m3. The foundation is made in the form of a round reinforced concrete slab with a diameter of 20.4 m. The characteristics of the soil are established by the results of geotechnical surveys. The calculation according to the Winkler model (elastic base plate with one coefficient of subgrade reaction) was performed in the "Cross" module of the SCAD Office software package. With a total load on the foundation of 2741 tf, its average subsidence is 2.15 cm. The calculation according to the model of three-dimensional finite elements of cubic shape was performed in the environment of the SCAD Office software package. The average subsidence of the foundation is 2.4 cm. The calculation by the method of layer-by-layer summation according to the instructions of DBN B.2.1-10: 2018 gave the subsidence of the foundation slab equal to 13.7 cm. The actual average subsidence of the foundation during the observation period in different areas of the foundation was 1.1… 2.4 cm and averaged 1.75 cm. The comparison of the analyzed methods for determining the subsidence of the foundation indicates the closeness of the results of calculations on the model of the slab on an elastic basis and the model of three-dimensional finite elements to the actual value of subsidence and the greatly higher result of the calculation by layer summation. The use of the latter method leads to excessive reliability in the design of foundations.Item Методика розрахунку несучої здатності сонячних панелей як елемента забезпечення енергоефективності будівель(ЦНТУ, 2022) Настоящий, В. А.; Пашинський, В. А.; Пашинський, М. В.; Якименко, М. С.; Nastoyashchiy, V.; Pashynskyi, V.; Pashynskyi, M.; Yakimenko, S.Запропонована методика розрахунку несучої здатності сонячних панелей, розташованих на дахах малоповерхових будинків. Отримані робочі формули для визначення допустимого прольоту панелі типової конструкції залежно від навантажень, відношення розмірів її сторін та кута нахилу до горизонту. З урахуванням кліматичних навантажень у м. Кропивницький встановлено, що вирішальним є розрахунок за вимогами другого граничного стану. Допустимий проліт сонячної панелі з обшивками із загартованого скла товщиною 3 мм може змінюватися від 0,68 м до 1,36 м. Extensive use of solar panels for providing low-rise buildings with electricity has led to the development of methods for assessing the load-bearing capacity of solar panels, taking into account the size of the panel, the angle of inclination to the horizon and climatic loads in a given geographical area. The solar panels are calculated as plates hinged along the contour. Self-weight loads of the panel, snow, wind and ice loads are determined according to DBN B.1.2-2: 2006 "Loads and impacts" and are reduced to a component that is normal to the plane of the panel. Working formulas were obtained for determining the extreme and operational design values of loads, checking the strength and deflection of panels, as well as the maximum allowable spans according to the criteria of strength and structural rigidity. An example of calculation of solar panels placed at angles of inclination to the horizon from 15° to 75° on the roof of a building in Kropyvnytskyi were performed. Strength checks should be performed on combinations of panel self-weight, snow and maximum wind pressure. Deflection check at small angles of panels inclination is carried out taking into account the same combination of loads, and at big angles of inclination - taking into account only ice load. In all cases, the condition of rigidity is decisive. Permissible span L (smaller size) of a solar panel with 3 mm tempered glass sheathing in the conditions of Kropyvnytskyi varies from 0.68 m to 1.36 m. It increases as the angle of inclination increases and as the B/L ratio approaches to 1. The allowable span varies by 13…16% with length ratio of the larger side of solar panel to the smaller one in the range from 1.4 to 2.0. This allows to take the values of the allowable span, corresponding to the ratio of the parties B/L=2.0 in order to simplify the safety margin. The obtained working formulas and their implementation in the form of a calculation sheet in Microsoft Excel allows to perform similar calculations for other source data. Further research focuses on the establishment of allowable spans of solar panels of typical design in the conditions of each of the regions of Ukraine.