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Information × Registration Number 0217U003190, 0115U002205 , R & D reports Title Studies on the stress/strain state of steel fiber concrete structures, improvement of methods for estimation of their reliability and production technology popup.stage_title Head Pasternak Iaroslav Mykhailovych, Доктор фізико-математичних наук Registration Date 24-01-2017 Organization Lutsk National Technical University popup.description2 During conducting of this scientific research the following scientific and technical results are obtained: - the methodology for calculation of shells of negative Gaussian curvature for different boundary conditions and loadings is developed and practically applied using the finite difference technique. Finite difference equations are obtained for strength and stability in linear formulation for internal nodes of a shell under different boundary conditions applied; - computer program "Calculation of shells" is developed for calculation of strains and study of stability of revolution shells with negative Gaussian curvature like single-cavity hyperbolic paraboloid; - it is economically substantiated the usage of steel fiber concrete with enforcement percentage 1.5% in non-pressure pipes of circular cross-section comparing to ferroconcrete; - the design of steel fiber concrete tray is developed for road drainage at highways; -- it is experimentally proved that fracture of thin-walled pipe made of SFC occurs after development of four plastic hinges and separation of a ring onto for rigid discs, which are in the limit equilibrium. This leads to redistribution of moments at the boundary of a SFC pipe; - it is observed that first observable cracks in trays and pipes made of steel fiber concrete under one-time loading in most cases occured under one or two cycles of loading under limit loading comparing to samples of ferroconcrete in which they were observed under loading of 0.3...0.4 of maximal bearing capacity of the cross-section; - it is developed the design of thin-walled steel fiber concrete shell for ceiling of the shape of hyperbolic paraboloid, which has better strength comparing to same ceiling structures of ferroconcrete and enforced concrete; - it is experimentally proved that cyclic loading, which is less than 0.70 of rupture ones, does not significantly influence either overall and residual strain, or reduction of strength and fracture toughness of trays and pipes of steel fiber concrete, i.e. they has elastic behavior. The same time, residual deformations of 10...25 % are observed in ferroconcrete samples under repeated loading of 0.60 of rupture ones. The same are observed in trays and pipes of SFC under repeated loading of 0.85 of rupture one after 5-7 cycle; - production technology is improved for non-pressure pipes and drainage trays of steel fiber concrete. Keywords: hyperbolic paraboloid; hypar; thin-walled shell; pipe; tray; ferroconcrete; steel fiber concrete, steel fiber; short-term loading; repeated loading; bearing capacity; deformability; fracture toughness; finite element method; Program Complex LIRA. Product Description popup.authors Андрійчук Олександр Валентинович Бабич Володимир Євгенійович Гречко Олександр Григорович Оласюк Павло Ярославович Пасічник Руслан Володимирович Ротко Вікторія Олександрівна Ужегов Сергій Олегович Ужегова Ольга Анатоліївна Хлопецький Роман Андрійович Шкирпан Катерина Валеріївна Ясюк Іван Миколайович Яцина Микола Георгійович Ящинський Андрій Леонідович popup.nrat_date 2020-04-02 Close