Browsing by Author "Ovchynnykov, Pavlo A."

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    Parameters of Typical Continuous Steel Truss Spans under a Yigh-Speed Movement
    (Дніпропетровський національний університет залізничного транспорту ім. акад. В. Лазаряна, Дніпро, 2017) Reshetnov, Artem Yu.; Solomka, Valentina I.; Ovchynnykov, Pavlo A.
    ENG: Purpose. Determination of the stress-strain state of a typical continuous steel truss span by calculation according to national norms and computer simulation in the conditions of passage of high-speed passenger trains. Methodology. In this work, the stress-strain state of a continuous truss span of the typical project No. 3 501.2-166 for the possibility of its application in areas with perspective high-speed railway traffic was investigated. Calculation of the specified span structure for DBN V.2.3-14-2006 «Constructions of transport. Bridges and pipes. Design rules» for railroad loading С14 was executed. The cross-sections of the elements of a continuous truss span were calculated and the necessary checks performed. For the given span structure in the software complex a model was developed and the stress-strain state at various speeds of railway transport according to European and national norms was investigated. The acceleration and deflection of a continuous steel truss span were determined and their comparison with normative requirements was performed. Findings. As a result of simulation in the software complex for a continuous steel truss span, acceleration and deflection under the action of cargo and passenger load at different speeds of movement were determined. The cross-sections of the elements of a continuous steel truss span were calculated. Originality. The results of the study can be applied in the development of national regulatory documents on high-speed rail transport and in the design of bridge structures with continuous truss spans in areas with high and higher-speed railway traffic. Practical value. The obtained results of the research will allow to effectively use continuous steel truss spans of typical designs in areas with high– and higher-speed railway traffic.
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    Predicting Changes of the State of a Bridge Reinforced With Concrete Superstructures in View of Operational Changes
    (Uniwersytet Zielonogórski, Poland, 2019) Ovchynnykov, Pavlo A.; Dubinchyk, Olha I.; Tiutkin, Oleksii L.; Kildieiev, Vitalii R.; Sedin, Volodymyr; Bikus, Kateryna
    ENG: Purpose. Bridges are the most durable and heavy duty transport facilities. Therefore, the solution of scientific and technical problems of superstructure service life predicting in the context of defect and damage accumulation that is, taking into account changes in operating conditions is on the front burner. Methodology. To solve the problem of superstructure service life predicting, the work proposes the bases and methodological developments of creep theory with increasing loads as well as regression analysis of the laboratory experiments results. Findings. The main parameters of reinforcement corrosion growth in the concrete cracks were determined under laboratory experiments. Based on the obtained results the approximate analytical dependences concerning reinforcement corrosion depth change in time at a constant value of crack width were selected. The paper substantiates validity of the analytical dependences as a result of regression analysis; proposes formulas for determining the corrosion rate of rebar in reinforced concrete superstructures. The obtained analytical dependences allowed for development of the process of predicting superstructure state changes in view of operational changes. Originality. For the first time, using laboratory experiments, the development of reinforcement corrosion in concrete cracks was determined together with assessment of time-varying corrosion depth. Practical value. Approximating analytical dependences, with a high level of confidence (95%), allow predicting reasonably the crack width in reinforced concrete superstructure. This is a significant practical value for bridge superstructure service life predicting in the context of defect and damage accumulation that is, taking into account changes in operating conditions. Formulas for determining the corrosion rate in rebar with the ability to predict the active area of corroded reinforcement have also practical value.
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    The Research of the Deflected Mode for the Steel Truss Bridge Span with Upper-Level Traffic by the Computer Modeling Method
    (Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпропетровськ, 2015) Ovchynnykov, Pavlo A.; Solomka, Valentina; Miroshnik, Vitaliy; Pinchuk, Anna
    ENG: Purpose. To confirm the result of bridge span classification by using the computer modelling for truss span with upper-level traffic and polygonal lover belt and to determine minimal sufficient complexity of computational model that provides a possibility of adequate numerical calculation of given structure. Methodology. The result confirmation was executed by the comparison of stresses, that were yielded as a result of truss’ model loading with loads of predetermined class, with allowed stresses that were adopted for the determination of the afore-mentioned loading. The determination of optimal computational model was performed by the comparison of calculation results for models of different complexities. Findings. The results of the span modelling are similar enough to the results of it’s calculation, which confirms the accuracy of both methods and provides obvious idea about work of truss elements and critical places. The comparison of calculation results of different models showed that the using of shaft model with hard junctions and elements’ bending accounting is optimal. Originality. Computer modeling was used to confirm the results of span classification, which was conducted by the standard method. An optimal computational model was determined for trusses that are similar to given. Practical value. Results of analytical calculation were confirmed with demonstration of critical elements and obvious demonstration of results. The optimization of the model allows to lower calculation time and complexity of executing them for similar trusses.
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    Study of Railway Steel Bridges’ Behaviour in Order to Identify the Causes of Their Defects
    (Óbuda University, Budapest, Hungary, 2022) Kliuchnyk, Serhii; Ovchynnykov, Pavlo A.
    ENG: The purpose of this work is to clarify the causes and mechanism of premature origin of defects in the elements of the bridge deck with the storey connection in steel span structures of railway bridges by studying the stress-strain state of their deck beams. Research aimed at extending the service life and increasing the carrying capacity of metal girder structures with a low load class and at the introduction of a new design solution for connecting the nodes of the deck beams, which is extremely important to ensure the necessary railway capacity and train safety. Service life and reliability of stringer beams of a deck definitively defines a service life and carrying capacity of all span structure. In order to deepen the analysis of the experimental data of the tested structures, calculations of the structure with the initial data, that fully correspond to the experimental span structure, were performed. For theoretical researches the underslung span structure with through trusses, designed by "Proektstalkonstruktsiya" with the nominal span of Ln = 44,0 m with a storey carriageway was chosen, as the one having the greatest number of defects in nodes of stringers support by the floor beams. According to the results of calculations and computer simulations, it is determined that the main cause of cracks is the structural imperfection of the aforementioned nodes, that is typical of similar structures.