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624.012.45 - - 05.23.01 – , 19 – є . . , . _______________ .. - , ..., – 2021 2 .. - - . – . ( ) 05.23.01 – , (192 – ). – , , , 2021. - . ґ , , , ’ . , . . - . – (). . , , . . . , - () , (). 3 , , , , . , - () . , . l = 300 b×h = 8×16 l1,2 = 140 . 25/30. 11-1,2 - 12-1,2 , . 11 – Ø14 500 12 – Ø10 500. - 12 ’є , µfv = 1%. 13-1,2 ’є µfv = 2%. d = 1 l = 50 , -. . 4 b×h = 10×16 , , l1,2 = 140 . , ’є, µfv = 1%. 21 є ’є, 22 , , 23 – , t = 40 , . , - . . 8 – 12 % , . 5 – 7 , , (wk). . ґ - . є , , . , є . 5 . - (), , . «» - , 21, 22, 23. - , , №14 , є « – » (σ – ɛ). , «», . - - . - . - . . , - , є ’є . : , , , - , , , , . 6 С У: 1. . ., . - . , , . 2019. 37. 97-105. ( : - , ). 2. . ., . - . . 2019. 12. 3-12. ( : - ). 3. .., . - - . . 2020. 14. 26-35. ( : - , ). 4. . ., . ., .. - . . 2020. 13. 3-11. ( : - , ). 5. . . , , . 2012. 24. 208-214. ( 7 : ). 6. . - . , , . 2015. 31. 460-467. ( : - ). 7. . . , , . 2016. 32. 220-225. ( : - , ). С ч , щ ч ч : 8. Babych Y. M., Andriichuk O. V. , Kysliuk D. Y, Savitskiy V. V., Ninichuk M.V. Results of experimental research of deformability and crack-resistance of two span continuous reinforced concrete beams with combined reinforcement. IOP Conference Series: Materials Science and Engineering. 2019. Vol. 708. 012043. DOI: 10.1088/1757-899X/708/1/012043 (Web of Science, Scopus). ( : - ). 9. Babych Y. M., Andriichuk O. V., Kysliuk D. Y., Ninichuk M.V. Experimental Research of Strength Characteristics of Continuous Reinforced Concrete Beams with Combined Reinforcement, and Modelling Their Work by the Finite Element Method. Proceedings of EcoComfort 2020. Lecture Notes in Civil Engineering. 2020. Vol. 100. P. 18–25. DOI: 10.1007/978-3-030-57340-9_3 (Scopus). ( : - ). 8 ABSTRACT (Ninichuk M.V. Stress-strain state and calculation ofcontinuous combined- reinforced concrete beams. – Qualified scientific work on the rights of the manuscript. Disertation for a Candidate Degree in Engineering (Doctor of Philosophy) in the specialty 05.23.01 – Building Structures, Buildings and Structures »(192 - Civil Engineering and Civil Engineering). – Lutsk National Technical University, National University of Water and Enviromental Engineering, Rivne, 2020. The dissertation is devoted to the analysis of the stress-strain state, strenhth and bearing capacity of the continuous combined reinforced concrete beams. The introduction substantiates the relevance of the topic, formulates the purpose and objectives of the study, scientific novelty and practical significance of the work, presents its general characteristics and connection with scientific programs. The first section analyzes the scope of inseparable reinforced concrete beams, features of their operation and design. The boundary conditions of redistribution of forces in such beams and methods of their calculation are described. An analysis of the results of experimental studies of the stress-strain state of continuous beams under single and repeated loads. Material for building structures – steel fiber concrete (SFRC) is considered. The use of fiber in concrete is analyzed. General information on the application of SFRC in the practice of construction of reinforced concrete structures, their advantages and disadvantages, known methods of their calculation and features of work under load. The analysis of experimental researches of work of designs with use of SFRC is carried out. The purpose and tasks of research of dissertation work are formulated. The second section is devoted to the methodology of experimental studies of strength and deformation characteristics, stress-strain state (SSS) of continuous beams of reinforced concrete, SFRC and combined-reinforced To study the features of strength and deformation characteristics, SSS of continuous reinforced concrete beams, as well as the work of these elements under one- time short-term loads, it is advisable to conduct two series of experimental studies, in accordance with the goals and objectives set in the scientific work. 9 In the first series the bearing capacity and deformability of reinforced concrete, combined-reinforced and classical-reinforced (typical) reinforced concrete two-span beams were investigated and compared. Reinforcement was performed so that the consumption of steel in all types of beams was the same. The test specimens were inseparable two-span reinforced concrete beams with a length of l = 300 cm with cross- sectional dimensions b × h = 8 × 16 cm with a span length of l1.2 = 140 cm. In the second series of experiments, the influence of the type of additional dispersed steel fiber reinforcement of different zones of inseparable reinforced concrete beams on their strength characteristics and stress-strain state was studied. Additional dispersed reinforcement of the beams of the second series was performed in such a way that the samples had different filling of the volume with fibers, with the same relative percentage of reinforcement equal to µfv = 1%. In particular, beams 2B1 were reinforced with fibers throughout their volume, in beams 2B2 fibers were applied only in stretched areas of concrete, which was conditionally half the height of the beam, and beams 2B3 - in stretched areas, but only to a height t = 40 mm from the outer edge of the beam equal to twice the height of the protective layer of concrete. The program of experimental research of continuous beams, selection of material for production of concrete-matrix and timbering for prototypes is described in detail. The scheme of specially constructed test set up and the scheme of arrangement of measuring devices is described. During the study of the beams, the load was applied in steps of 8 - 12% of the destructive force, which is determined by the theoretical method during the calculation. After each load step, exposure was performed for 5 - 7 min, during which the readings of indicators, indicators of the strain gauge complex were taken and the width of crack opening (wk) was measured. The method of testing prism samples for short-term axial tension and compression and cube samples for short-term axial compression is also covered. The third section is devoted to a thorough analysis of the obtained results of experimental studies of the work of combined-reinforced continuous reinforced concrete beams with different types of reinforcement. The operation of beams under the action of 10 short-term load, the nature of deformation of materials, the processes of crack formation and the features of redistribution of forces are described in detail. As a result of experimental studies it was confirmed that the use of additional dispersed steel fiber reinforcement of continuous reinforced concrete beams increases their load-bearing capacity and rigidity, which reduces the deflections and width of cracks and changes the nature of redistribution of forces compared to typical reinforced concrete. In the fourth section the simulation of the operation of continuous combined- reinforced beams by the finite element method (FEM) is carried out, the numerical values of stresses, bending moments and displacements are determined. Using LIRA- SAPR was modeled and calculated continuous combined-reinforced beams with parameters corresponding to the prototypes of type 2B1, 2B2, 2B3. The method of determining the characteristics of the stress-strain state of inseparable combined-reinforced beams with the help of a deformation model taking into account the complete diagrams of the work of reinforced concrete in tension has been improved. A simplified engineering method for determining the bearing capacity of normal sections of combined-reinforced reinforced concrete bending elements is proposed. The method of determining the magnitude of bending moments in inseparable combined-reinforced beams taking into account the redistribution of forces has been improved. The obtained theoretical data are compared with the results of experimental researches. On the basis of the conducted researches the general conclusions for application, modeling and calculation of inseparable combined-reinforced beams are formulated, and their results are introduced at designing of real objects and in educational process. Keywords: reinforced concrete, steel fiber, fiber, beam, stress-strain state, fracture resistance, redistribution of efforts. 11 ……………………………………………………………………………….. 14 1. - , Є……………………………..…. 20 1.1. - … 20 1.2. , . 22 1.2.1. …..…………………………………………………………...... 22 1.2.2. , ……………………………..…. 23 1.3. ………………... 27 1.3.1. …………………………………………………………………………. 27 1.3.2.

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