Victor Levchenko, Nikolay Nevgen, Evgeniy Dmitrenko, Nelya Gaevskaya
The Economic Basis for Determining the Structural Efficiency of Buildings and Structures
FSBEI HE «Donbas National Academy of Civil Engineering and Architecture»
Abstract. In order to determine the cost-effectiveness of the use of different materials correctly, the criterion and model for setting the present value must be chosen, taking into account the influence of the main factors. There are several views on the criteria for assessing cost-effectiveness and justifying the choice of type of structures: various criteria are proposed and used in practice. In the current «Typical Methodology for Determining the Economic Efficiency of Capital Investments» the criterion for the economic efficiency of capital investments for the national economy is the increase in national income, and the indicator of comparative economic efficiency is the minimum incurred costs. It is known that in practice of design and construction, the type (material) of constructions or structural solutions is chosen based on a comparison of indicators such as material consumption in construction, weight of constructions, labor intensity and duration of construction, degree of assembly, number of standard sizes of constructions, and profitability of the construction organization. The minimum or maximum value of these indicators cannot serve as a criterion characterizing the efficiency of using certain constructions in general.
Keywords: efficiency, profitability, wholesale cost, property, probability.
Eduard Savenko, Sergey Matvienko, Vladislav Simonov, Nikolay Belanov, Alexander Gudolin
Technology of Applying the Method of Electrohydraulic Display for Parts Restoration
FSBEI HE «Donbas National Academy of Civil Engineering and Architecture»
Abstract. The article describes a method for restoring piston pins of internal combustion engines through the use of an electro-hydraulic distribution method. An analysis of the features of electrohydraulic treatment has established that this process is one of the promising methods for restoring piston pins of internal combustion engines. This method makes it possible to restore piston pins of all types of engines, from any material and with any internal cross-section geometry. The dependence on the conditions of chemical and thermal treatment of piston pins has been determined and a technological recovery process has been developed. A technological process has been developed for the recovery of disposable cartridges for the electrohydraulic dispensing process. The main modes of the electrohydraulic distribution process are calculated. A section for the restoration of piston pins and other types of parts has been designed. Technological schemes for restoring cylindrical car parts are presented. The calculation method was used to determine the modes and parameters of the process of electrohydraulic expansion of piston pins while maintaining their fatigue life, static strength and wear resistance.
Keywords: restoration, piston pin, electrohydraulic expansion, wear, repair size, electric discharge, plastic deformation of metal, electromagnetic energy, energy of explosives.
Tatyana Kitsenko, Elena Yegorova, Sergei Lakhtarina, Irina Petrik, Ekaterina Boroday,
Victor Zavalnuy
Study of the Properties of Heavy Concretes with the use of Granite Screening Instead of
Quartz Sand
FSBEI HE «Donbas National Academy of Civil Engineering and Architecture»
Abstract. The influence of the use of granite screening on the basic properties of heavy concretes has been studied. It has been established that granite screenings of the Telmanovskoye deposit meet the requirements of the current interstate standard 31424-2010, which allows the use of a material with a fraction of 0–5 mm instead of quartz sand in heavy concretes. Studies have shown that replacing quartz sand with granite screening in heavy concrete leads to a decrease in the mobility of the concrete mixture. However, it has been found that when using granite screening instead of quartz sand, the strength of concrete increases. Thus, the introduction of granite screenings in the composition of concrete in the amount of 25 % of the mass of sand leads to an increase in the strength of concrete by 8 % compared with the initial strength. The complete replacement of quartz sand with granite also does not reduce the strength characteristics of concrete. Steaming of the studied concrete samples leads to a similar increase in the strength of concrete with an appropriate content of granite screening.
Keywords: heavy concrete, granite screening, quartz sand, granulometric composition, concrete strength, steaming.
Andrey Nedorezov, Nikolay Nevgen, Tamara Zagoruiko, Nikita Sevostyanov
Analysis of Experimental Studies of Fragments of Building Structures for Progressive Collapse
FSBEI HE «Donbas National Academy of Civil Engineering and Architecture»
Abstract. The article examines the history of the problem of buildings and structures assessment of resistance to progressive collapse. The main prerequisites for the beginning of the study on the prevention of progressive collapse in Russia, the United States and the European Union countries have been identified. The analysis of pilot research of fragments of building structures for progressive collapse has been carried out. Foreign and domestic approaches to the methods of pilot research of fragments of building structures are considered, and their main features are revealed. Based on the analysis of recent studies and publications, it has been concluded that with an increase in static uncertainty and structural instability, resistance to progressive collapse increases, and dynamic overloading occurs in the surviving structural elements with a sudden application of load. It is also noted that dynamic overloading of the entire system is more dangerous than switching off the carrier element. Theoretical and experimental studies of the protection of structures from progressive collapse are necessary for a more detailed study of the behavior of structures under the influence of special loads.
Keywords: progressive collapse, emergency impact, local collapse, stress-strain state.