Determination of Strain Distribution and Curvature in a Reinforced Concrete Section Subjected to Bending Moment and Longitudinal Load

10.14359/7574 ◽  
1967 ◽  
Vol 64 (7) ◽  
2021 ◽  
Vol 27 (3) ◽  
pp. 212-216
Author(s):  
Yaroslav Blikharskyy ◽  
Jacek Selejdak ◽  
Taras Bobalo ◽  
Roman Khmil ◽  
Mykhailo Volynets

Abstract This article presents the materials of deformability studies of pre-stressed steel-concrete beams reinforced with a package of reinforcement with different ratio of tape and rebar in the pure bending moment zone. The aim of the research was determination of the reinforcement percentage influence, for pre-stressed reinforced concrete beams reinforced with a package of reinforcement on their deformability. Also, the aim was to evaluate the effectiveness of using pre-stressed rebar in combined reinforcement. The practical significance of the experimental research is to study the deformability in pre-stressed bending elements with external tape and rebar reinforcement, taking into account the influence of different ratios of reinforcement areas within the combined reinforcement and development of proposals for such structures` calculation and design. The scientific novelty of the research is in obtaining the deformability characteristics of reinforced concrete beams reinforced with a package of reinforcement (tape and steel bars with periodic profile) with different ratios in the case of static loads` action.


Problems when calculating reinforced concrete structures based on the concrete deformation under compression diagram, which is presented both in Russian and foreign regulatory documents on the design of concrete and reinforced concrete structures are considered. The correctness of their compliance for all classes of concrete remains very approximate, especially a significant difference occurs when using Euronorm due to the different shape and sizes of the samples. At present, there are no methodical recommendations for determining the ultimate relative deformations of concrete under axial compression and the construction of curvilinear deformation diagrams, which leads to limited experimental data and, as a result, does not make it possible to enter more detailed ultimate strain values into domestic standards. The results of experimental studies to determine the ultimate relative deformations of concrete under compression for different classes of concrete, which allowed to make analytical dependences for the evaluation of the ultimate relative deformations and description of curvilinear deformation diagrams, are presented. The article discusses various options for using the deformation model to assess the stress-strain state of the structure, it is concluded that it is necessary to use not only the finite values of the ultimate deformations, but also their intermediate values. This requires reliable diagrams "s–e” for all classes of concrete. The difficulties of measuring deformations in concrete subjected to peak load, corresponding to the prismatic strength, as well as main cracks that appeared under conditions of long-term step loading are highlighted. Variants of more accurate measurements are proposed. Development and implementation of the new standard GOST "Concretes. Methods for determination of complete diagrams" on the basis of the developed method for obtaining complete diagrams of concrete deformation under compression for the evaluation of ultimate deformability of concrete under compression are necessary.


2020 ◽  
Vol 92 (6) ◽  
pp. 13-25
Author(s):  
Vl.I. KOLCHUNOV ◽  
◽  
A.I. DEMYANOV ◽  
M.M. MIHAILOV ◽  
◽  
...  

The article offers a method and program for experimental studies of reinforced concrete structures with cross-shaped spatial crack under torsion with bending, the main purpose of which is to check the design assumptions and experimental determination of the design parameters of the proposed calculation method. The conducted experimental studies provide an opportunity to test the proposed calculation apparatus and clarify the regularities for determining deflections, angles of rotation of extreme sections, and stresses in the compressed zone of concrete. For analysis, the article presents a typical experimental scheme for the formation and development of cracks in the form of a sweep, as well as characteristic graphs of the dependence of the angles of rotation of end sections.


2008 ◽  
Vol 59 (5) ◽  
pp. 605-610
Author(s):  
Alexandru Pupazescu ◽  
Stefan Minoiu ◽  
Constantin Manea

The paper contains an assessment of the sylphons lifetime for multiaxial fatigue. Three criteria were used two based on s � N diagram and one based on energy. For a more accurate determination of the sylphons lifetime the stress and the strain distribution been determined using FEM, the tensile curve of the steel W 4541 at elevated temperature.


CORROSION ◽  
1988 ◽  
Vol 44 (10) ◽  
pp. 761-765 ◽  
Author(s):  
S. Feliu ◽  
J. A. Gonzalez ◽  
C. Andrade ◽  
V. Feliu

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3438
Author(s):  
Michał Szczecina ◽  
Andrzej Winnicki

This paper discusses a choice of the most rational reinforcement details for frame corners subjected to opening bending moment. Frame corners formed from elements of both the same and different cross section heights are considered. The case of corners formed of elements of different cross section is not considered in Eurocode 2 and is very rarely described in handbooks. Several reinforcement details with both the same and different cross section heights are presented. The authors introduce a new reinforcement detail for the different cross section heights. The considered details are comprised of the primary reinforcement in the form of straight bars and loops and the additional reinforcement in the form of diagonal bars or stirrups or a combination of both diagonal stirrups and bars. Two methods of static analysis, strut-and-tie method (S&T) and finite element method (FEM), are used in the research. FEM calculations are performed with Abaqus software using the Concrete Damaged Plasticity model (CDP) for concrete and the classical metal plasticity model for reinforcing steel. The crucial CDP parameters, relaxation time and dilatation angle, were calibrated in numerical tests in Abaqus. The analysis of results from the S&T and FE methods allowed for the determination of the most rational reinforcement details.


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