Browsing by Author "Netesa, Andrii M."
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Item Application Prospects of Threaded Joint of Armature(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпропетровськ, 2014) Radkevych, Anatolii V.; Netesa, Andrii M.ENG: Purpose. One of the main technological operations of buildings construction on the basis of monolithic frame systems is the production of mesh reinforcement. The current interest is the new ways specification of advanced bonding armature techniques without reliability weakness and design of the building in whole, as well as the finding of use prospects of screw-threaded joint of armature as the most technological and economic method of re-bars joints. Methodology. Advantages and disadvantages analysis of existing rebar compound technologies was implemented by couplings of different types and constructions. The most promising vertical constructions for the vertical bars joints in frameworks were determined. Findings. Researches of existing technologies of rebar joints by the couplings of different construction were carried out. The installation method of mesh reinforcement of vertical structural elements with the use of the special catching devices was developed. It allows considerably accelerating installation of mesh reinforcement. Originality. Regularity of labor intensiveness change of mesh reinforcement installation of columns at armature joint in vertical position by threaded couplings with the help of catching devices using special construction was determined. This allows substantially reducing the labor expenditures during installation of these elements. Dependency of labor intensiveness and cost of lap welding armature joints, by tub-seam welding and by thread coupling depending on its diameter was designated. Regularity of labor intensiveness changes of installation at armature joints by different methods taking into account preparatory works was defined. Practical value. The analysis of mechanical armature joints techniques was conducted. It will allow selecting methods of armature joints to increase the speed of construction works more economical and effective.Item Determination and Ranging of Organizational and Technological Factors that Define the Rational Decisions of Re-Bars Connection(Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan, Dnipro, 2017) Radkevych, Anatolii V.; Netesa, Andrii M.ENG: Purpose. The paper proposes: 1) determination and formulation of factors that influence the choice of rational method for joining re-bars of vertical support members of reinforced concrete frame; 2) determination of factor parameters; 3) ranging of factors by the expert evaluation (Delphi) method. Methodology. In order to achieve research objectives, it is necessary to carry out analysis of existent rebar connection methods, determination of factors and parameter variation limits for each of the methods. Performing factor ranking by the expert evaluation method. Findings. The results of the questioning materials of 14 experts in the area of monolithic construction allowed setting the following: when choosing the rational re-bars connections, the most significant values are the factors that define the time parameters: possibility of carcassing, time of joining the re-bars, length of rebar cage, prior operation run time, operation time of main lifting equipment. Herewith the factors that define the rebar cage parameters have a direct relation to the work performance time, as they determine the amount of bar connections in the course of building erection over wide range. Economic factors – rebar connection cost and quality control cost – have the less value. It is obvious that in the conditions of considerable construction expenses it is advantageous for an investor to increase the rebar joining cost for the work growth rate. Structural and technological factors have the least value: origin of eccentric load transmission between re-bars, possibility of use of the thermally workhardened re-bars of А500 and higher grades, work category for implementation of works, necessity to use the scaffold and appurtenances for re-enforcement of constructions. The reason is analogical: a contractor is ready to go to complication of technology with the purpose of reduction of the facility erection terms. As the calculated Pearson’s matching criterion χ 2 = 47.24 is higher than the tabular one (22.36203), then the obtained concordance coefficient W=0.26 is not casual value, and that is why the obtained results make sense and can be used in further researches. Originality. The author obtained factors that influence the choice of the rational method for re-bars connection the most. Practical value. Ranging of factors will allow objective approaching to the problem of choice of re-bars connection method, optimizing the labour and material costs, and also reducing the construction time.Item Determining the Rational Compositions of Low-Strength Concretes(НВП ПП «Технологічний Центр», Харків, 2019) Shishkin, Alexsander; Netesa, Nikolay I.; Netesa, Andrii M.ENG: The paper reports regularities in the influence of the amount of waste from iron ore enrichment at a rational composition of grain components on strength of concretes with a minimal cement consumption. Low-strength concretes are used in the non-reinforced structures, so they are not subject to the requirement for the minimal cement consumption in order to ensure the protection of reinforcement against corrosion. A significant reduction in cement consumption by low-strength concretes while maintaining the required strength can be ensured by a rational grain composition of the components of a concrete mixture, which is characterized by the ratio between large, medium, and small components of 52:23:25. In such formulations, the required amount of fine-grained component is achieved by introducing the fine-grained components, made, for example, from the secondary products of industry, specifically the iron ore dressing waste. The result of the research conducted established that ensuring the rational grain composition of the concrete mixture components provides for the required low strength of concrete at a significantly less cement consumption than that for concretes whose composition is defined in line with other procedures. It was found that it is advisable to use the iron ore dressing waste as a fine-grained supplement, the introduction of which at rational amount ensures significant improvement in the efficiency of cement utilization in concretes of low strength. Application of concretes of the proposed formulations, which could be used for temporary structures ‒ a concrete cap for making floor slabs at formwork-free molding, could save a significant amount of cement, and dispose of the secondary products from industry. The research has also established that the use of plasticizers makes it possible to obtain concretes of the rational grain composition with the required workability.Item Problems of Development of an Underground Transport Infrastructure of Cities(The Silesian University of Technology, Faculty of Transport. Katowice, Poland, 2020) Pshynko, Oleksandr M.; Radkevych, Anatolii V.; Netesa, Nikolay I.; Netesa, Andrii M.ENG: Summary. The goal of this article is to determine rational constructional and technological options for the development of underground space, in particular, the arrangement of underground parking lots under the specific hydrogeological conditions of Dnipro city. In this article, the best practices in the construction of similar facilities in the world are discussed. Arrangements for individual structural elements and structures as a whole were considered. The main resources for their implementation are determined, the most important performance indicators are calculated, their comparison is carried out and proposals for the use of individual technological concepts are developed. The experience of underground space development in Dnipro city is studied and the problems of construction of underground structures under specific difficult hydrogeological conditions are identified. The proposed technological concepts make it possible to implement such design solutions under difficult hydrogeological conditions with dense development and preservation of historical buildings in the city.Item Rational Compounds of Low-Strength Concrete with Improved Coefficient of Efficiency of Cement Use(Trans Tech Publications LTD, Switzerland, 2019) Netesa, Andrii M.; Netesa, Nikolay I.; Radkevych, Anatolii V.; Yakovliev, Serhii O.ENG: Abstract. The purpose of the research findings, given in article, is aimed to determine the rational compounds of concrete with an average cubic compressive strength less than 20 MPa with minimum required expenditures of cement. To reach the goal, mathematical planning of the experiment was used with variability of cement consumption from 90 to 190 kg / m3 in the compositions of the concrete mixture, and for the fine-grained filler from tails of processed ores, the consumption was like at 100 to 400 kg / m3. The result of processing experiments has shown us the dependences of the change in strength and coefficient of efficiency of the use of cement of the factors involved. Optimized values increase most intensively with minimum cement consumption and a change in the consumption of fine filler within the limits of the study. The highest coefficient of efficiency of use of cement is expressed by the ratio of the achieved strength per unit mass of used cement in the concrete mix and it was obtained at a cement consumption of 90 kg / m3 and a filler of 400 kg / m3. Using the obtained dependences of optimized values on the factors under study, the composition of concrete may be predicted with a strength up to 20 MPa with the required amount of filler.