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  • Numerical modeling of the stress-strain state of compressed reinforced concrete pillars reinforced with composite materials

    Currently, a large amount of research is devoted to the use of polymer composite materials applied for increasing the strength and durability of reinforced concrete elements. In compressed reinforced concrete columns, the bearing capacity depends on the eccentricity of the external force application and the corresponding stress-strain state, as well as on the arrangement and quantity of composite materials bonded to the surface of the structure. The choice of the arrangement scheme of composite materials depending on the stress state of the structure is of current interest for researchers. At the same time, studies conducted on centrally compressed elements often have contradictory effects. The main purpose of this study is to perform numerical experiment of a digital model for the centrally compressed concrete column reinforced with composite materials. The calculation results for 3 short columns with different reinforcement schemes are presented. It is shown that the use of composite materials to reinforce structures increases the bearing capacity up to 10%. Based on the study results, recommendations on the optimal schemes of reinforcement with composite clamps of inflexible columns reinforced in the transverse direction are proposed.

    Keywords: reinforced concrete columns, normal sections, finite element modeling, reinforcement with composite materials

  • Investigation of the surface of calcined cobalt catalysts on zeolite supports

    The effect of a zeolite support on the physicochemical properties of cobalt catalysts prepared by the precipitation method and calcined at 400°C was studied. The values of the specific surface of the catalysts, the degree of cobalt reduction, and the dispersion of the metal were determined, and the presence of functional groups on the surface of the catalysts was determined by BET, TPV, TPD-H2, and IR spectroscopy.

    Keywords: catalyst, cobalt oxide, hydrocarbons, dispersion, active surface

  • Formation of the active surface of deposited cobalt catalysts

    The effect of a zeolite support on the physicochemical properties of cobalt catalysts was studied on a series of samples with zeolites ZSM-5, HY, and NaX. The catalysts were obtained by precipitation followed by mixing the precipitate with a zeolite support. Their properties were characterized by BET, TPR, TPD-H2, IR spectroscopy. The results of the analysis show that the type of zeolite support affects the specific surface area, reduction of deposited cobalt, and the structural properties of the active component of catalytic systems.

    Keywords: precipitated catalyst, cobalt, zeolite, dispersion, specific surface area, active component, synthetic fuel, degree of reduction

  • Surface characteristics of cobalt catalysts on NaX zeolite

    The physicochemical properties of cobalt catalysts on a NaX zeolite support have been studied. The parameters of the specific surface area, reduction of deposited cobalt, and structural properties of the active component of catalytic systems have been determined. To establish these properties, the methods of BET, TPR, TPD-H2, IR spectroscopy were used. It is shown that the preparation procedure has a significant effect on the physicochemical characteristics of the samples.

    Keywords: catalysts, cobalt, zeolite, dispersion, specific surface area of the active component

  • Principles of saving metal in reinforced concrete structures

    The question of economy of metal at production of building designs is considered. Measures for the organization of effective production in the current projects of high-rise and long-span buildings are proposed. Measures of increase of efficiency of construction are considered

    Keywords: organization of construction; economy of construction, production of building materials

  • Application of combined steel-concrete frame of high buildings

    The problem of erection of a combined frame in high-rise housing construction is studied. The issues of installation of structures, space-planning scheme of high-rise buildings. Organizational and economic ways of perfection of technology of high-rise housing construction are offered.

    Keywords: organization of construction; high-rise housing; reinforced concrete and steel structures

  • Application of fiber-reinforced concrete in reinforced concrete structures

    This article deals with the field of application of fiber-reinforced concrete, reveals the advantage of using fiber-reinforced concrete in comparison with conventional concrete. The efficiency analysis of the use of fiber-reinforced concrete is analyzed.

    Keywords: fiber concrete, concrete, reinforced concrete, structures, technologies, installation, fiberglass concrete, reinforced concrete structures, tension, prestress, basalt fiber concrete

  • The method of reduction of terms of construction of an industrial enterprise through the use of new precast-monolithic structures

    Covers the relevant issues of reduction of construction period by using prefabricated structures. The proposed method is confirmed by calculations proving its reliability and feasibility. When developing the method was considered economic component of the design and construction of industrial complexes

    Keywords: organization of construction; modular construction, industrial construction

  • Innovative methods of reinforcement of reinforced concrete prefabricated carbon-fiber grids

    The current problems with carbon reinforcement grids to enhance reliability of any engineering structures. Determined development prospects for new construction: carbon fiber reinforcement and Fibre concretes. The reinforcement with carbon fiber systems are designed for repair and reinforcement of bearing structures of buildings in order to eliminate the consequences of the destruction of concrete and reinforcement corrosion as a result of prolonged exposure to environmental factors and aggressive media in the process of operation of facilities .

    Keywords: reinforced concrete structures, innovation in construction, carbon fiber

  • Organizational engineering

    Discusses the problems of organizational engineering. The review is carried out in the historical dynamics of the industry development. The expediency of application of innovative engineering in the industry.

    Keywords: systems of environmental economy, organization and management, environmental protection system.

  • Main methods of compound details irregular optimal packing on sheet material problem solving

    The paper deals with review of main methods of compound details irregular optimal packing on sheet material problem solving. Existing methods and approaches to solve compound details irregular optimal packing on sheet material problem were descibed. The classification of such methods and approaches was proposed. The most perspective approaches to solve irregular packing problem were identified

    Keywords: cutting-packing, irregular shaped cutting, classification, methods, approaches, complex form