Relation between Breaking Stresses in the Strength Calculations of Reinforced Concrete Elements under the Deformation Mode in the Edition of Russian and Foreign Regulatory Documents

2019 ◽  
Vol 974 ◽  
pp. 653-658
Author(s):  
Valeriy A. Eryshev
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Deformation Mode ◽  
Concrete Element ◽  
Regulatory Documents ◽  
Functional Relations ◽  
Base Points ◽  
Requirements Documents ◽  
Concrete Elements ◽  
Analytical Expressions

Сorrespondence was established between the compressive strength grades of concrete numerically equal to the guaranteed compressive strength of a standard concrete cube and a standard concrete cylinder. Designated concrete resistances are assigned for the limiting states of the first group with a compressive strength grade of concrete. For the corresponding concrete grades, the reduction to unambiguous strains values at the base diagrams points is justified: at the top and at the end of the falling branch of the curvilinear diagrams. In accordance with the regulatory requirements, restrictions are imposed on the stress levels at the end of the falling diagrams branch at the maximum normalized strains values. Mathematical models establishing a uniform format for calculating single-valued strains values at base points of concrete diagrams have been developed taking into account accepted functional relations and the their assignment rules using the requirements documents tables. It is shown that with equal strains values and stresses at base points, analytical expressions describing diagrams recommended by requirement documents, different in their structure, give their identical outlines, the diagrams branches are the same. Relation between design models in the edition of Russian and foreign regulatory documents is correlated by the comparison of integral diagrams parameters and breaking stresses obtained with the calculation of reinforced concrete element under the deformation mode. As integral parameters of concrete deformation diagrams, it is recommended to use the areas bounded by diagrams branches and diagrams fineness coefficient. The diagram area for given values of the element curvature is equivalent to the magnitude of the breaking stress in the compressed concrete zone in the bent and compressed elements, and the stress diagram in outline corresponds to this diagram.

scholarly journals INTEGRAL PARAMETERS OF CONCRETE DIAGRAMS FOR CALCULATIONS OF STRENGTH OF REINFORCED CONCRETE ELEMENTS USING THE DEFORMATION MODEL

2020 ◽  
Vol 16 (1) ◽  
pp. 25-37
Author(s):  
Vladimir Eryshev ◽  
Nickolay Karpenko ◽  
Artur Zhemchuyev
Keyword(s):  
Reinforced Concrete ◽  
Successive Approximations ◽  
Method Of Successive Approximations ◽  
Deformation Model ◽  
Concrete Element ◽  
Normative Documents ◽  
Functional Relationships ◽  
Regulatory Documents ◽  
Base Points ◽  
Analytical Expressions

In accordance with the requirements of regulatory documents, restrictions are introduced on stress levels at the end of the falling branch of the diagrams at the maximum normalized strain values. We have developed mathematical models that establish a uniform sequence for calculating the unambiguous values of deformations at the base points of concrete diagrams, taking into account the accepted functional relationships and the rules for their use according to the tables of normative documents. It was shown that for equal values of deformations and stresses at base points, analytical expressions of diagram recommended by regulatory documents, even if it differs in structure, give identical outlines, diagram branches coincide. The correlation between the calculation models by Russian and foreign regulatory documents was established by comparing the values of the integral parameters of the diagrams and the ultimate forces obtained by calculating the reinforced concrete element according to the deformation model. As integral parameters of concrete deformation diagrams, it was recommended to use areas bounded by diagram branches and diagram completeness coefficients. Analytical modeling of integral parameters allowed us to exclude the procedure for numerically summing stresses along elementary strips in a section and solving nonlinear equations by the method of successive approximations when calculating the strength of an element.

scholarly journals Strength criterion for a plane stress reinforced concrete element under a special action

Vestnik MGSU ◽  
2020 ◽  
pp. 1513-1522
Author(s):  
Natalia V. Fedorova ◽  
Vu Ngoc Tuyen ◽  
Igor A. Yakovenko
Keyword(s):  
Reinforced Concrete ◽  
Progressive Collapse ◽  
Concrete Strength ◽  
Limit State ◽  
Strength Criterion ◽  
Structural Systems ◽  
Variable Loading ◽  
Concrete Element ◽  
Theory Of Plasticity ◽  
Concrete Elements

Introduction. Problem solving focused on the protection of buildings and structures from progressive collapse and minimization of resources, needed for this purpose, is becoming increasingly important. In many countries, including Russia, this type of protection is incorporated into national regulatory documents, and, therefore, any research, aimed at developing effective ways to protect structural systems from progressive collapse under special actions, is particularly relevant. In this regard, the present article aims to formulate effective strength criteria for such anisotropic materials as reinforced concrete to analyze plane stressed reinforced concrete structures exposed to sudden structural transformations caused by the removal of one of bearing elements. Materials and methods. To solve this problem, a variant of the generalized theory of plasticity of concrete and reinforced concrete, developed by G.A. Geniev, is proposed for application to the case of variable loading of a plane stressed reinforced concrete element. The acceptability of generalization of the strength criterion, pursuant to the theory of plasticity of concrete and reinforced concrete under static loading, and the applicability of this criterion to variable static-dynamic loading of reinforced concrete are used as the main hypothesis. An algorithm of an approximate method is presented as a solution to this problem; it allows to analyze the considered stress-strain state of plane stressed reinforced concrete elements. Results. The numerical analysis of the obtained solution, compared with the results of the experimental studies, was used to evaluate the designed strength criterion for reinforced concrete elements located in the area where the column is connected to the girder of a monolithic reinforced concrete frame in case of a sudden restructuring of a structural system. It is found out that the qualitative nature of the destruction pattern of the area under research, obtained in experiments, corresponds to the destruction pattern, identified by virtue of the analysis performed using the proposed criterion. Conclusions. The variant of the reinforced concrete strength criterion designated for the variable loading of a plane stressed reinforced concrete element and an algorithm for its implementation, based on the theory of plasticity of concrete and reinforced concrete developed by G.A. Geniev, is applicable to the analysis of a special limit state of reinforced concrete elements of structural systems of frames of buildings and structures.

scholarly journals Sectional Analysis Procedure for Reinforced Concrete Members Subjected to Pure Torsion

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Jongkwon Choi ◽  
Seong-Cheol Lee
Keyword(s):  
Reinforced Concrete ◽  
Analysis Procedure ◽  
Reinforced Concrete Beams ◽  
Biaxial Stress ◽  
Pure Torsion ◽  
Concrete Element ◽  
Concrete Members ◽  
Stress States ◽  
Sectional Analysis ◽  
Concrete Elements

A sectional analysis procedure for reinforced concrete members subjected to pure torsion is presented in this paper. On the development of the analysis procedure, the reinforced concrete section is modeled with reinforced concrete elements subjected to biaxial stress states, on the basis of the thin-walled tube analogy. Each reinforced concrete element is analyzed with the modified compression field theory (MCFT) to take into account for compression softening and tension stiffening effects in cracked reinforced concrete. Considering analysis results of reinforced concrete elements, equilibrium, and compatibility on the section are checked. For verification of the developed analysis procedure, analytical predictions were compared with test results of 16 reinforced concrete beams subjected to a pure torsional load which are available in the literature. Comparison between predicted and experimentally obtained torque-twist responses showed that the proposed procedure is capable of capturing the ultimate torsional capacity as well as the angle of twist within a reasonable range.

Improving the Methodology for Calculating the Bearing Capacity of Eccentrically Compressed Reinforced Concrete Elements Based on the Use of the Refined Curvilinear Deformation Diagrams of Concrete and Reinforcement

2019 ◽  
Vol 974 ◽  
pp. 570-576
Author(s):  
Alexander I. Nikulin ◽  
Al-Khawaf Ali Fadhil Qasim
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Linear Equations ◽  
Resistance Force ◽  
Deformation Model ◽  
Concrete Element ◽  
Element Determination ◽  
Numerical Studies ◽  
Concrete Elements ◽  
Deformation Diagrams

The article proposes a new approach to improving the methodology for calculating the bearing capacity of the eccentrically compressed reinforced concrete elements for cases of their loading with large eccentricities. The basis of this technique is considered as a modified version of the deformation model for the reinforced concrete resistance force. The main feature of this model is the energy approach to transforming the reference diagrams of compression and concrete tension into the diagrams of non-uniform deformation, corresponding to the stress-strain state of the compressed and stretched zones of concrete in the cross section of the eccentrically compressed reinforced concrete structures. This way there is no falling branch in the concrete diagrams obtained by this method. A calculation diagram of the steel reinforcement deformation with a physical yield point was taken as a partial function, consisting of one linear and two non-linear equations. The proposed method also shows the possibility of taking into account the greatest curvature of an eccentrically compressed reinforced concrete element in the plane of its loading. The article presents all the necessary dependencies allowing the theoretical value of the carrying capacity of an eccentrically compressed reinforced concrete element determination. The results of the numerical studies performed using the design software developed by the authors for the personal computer are given.

RELIABILITY ANALYSIS OF REINFORCED CONCRETE FLEXURAL ELEMENT ON CRACKING BASED ON FRACTURE MECHANICS

2020 ◽  
pp. 40-44
Author(s):  
S. A. Solov’ev ◽  
O. V. Yarygina
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Stress Intensity ◽  
Fracture Mechanics ◽  
Reliability Analysis ◽  
Critical Stress ◽  
Intensity Coefficient ◽  
Concrete Compressive Strength ◽  
Concrete Element ◽  
Stress Intensity Coefficient

The article describes a probabilistic approach to the reliability analysis of a flexural reinforced concrete element by the cracking criterion using the provisions of fracture mechanics. Two mathematical models of limit state are proposed for reliability analysis: with the evaluation of the critical stress intensity coefficient directly and through the design concrete compressive strength. On the basis of regression analysis, the relationship between the critical stress intensity coefficient and the design concrete compressive strength is established which can be used in the inspection of reinforced concrete structural elements. The influence of the design concrete compressive strength on the failure (cracking) probability of the flexural reinforced concrete element is analyzed. The numerical example of reliability analysis is given for the reinforced concrete beam by the criterion of cracking. It is noted that the required level of reliability should be set for each structural object individually based on the acceptable risk value using economic and non-economic losses.

The development of A Simulation Tool for Numerical Modelling of High Flexure and High Shear Reinforced Concrete Elements

Teknik ◽  
2021 ◽  
Vol 42 (2) ◽  
pp. 106-116
Author(s):  
Nuroji Nuroji ◽  
Muhammad Rony Asshidiqie ◽  
Sukamta Sukamta ◽  
Ay Lie Han
Keyword(s):  
Reinforced Concrete ◽  
Element Model ◽  
Sensitivity Analyses ◽  
Shear Stresses ◽  
Concrete Element ◽  
Independent Variables ◽  
Accuracy And Precision ◽  
Set Up ◽  
High Degree ◽  
Concrete Elements

The weakness of full-scale testing of reinforced concrete elements in a laboratory is the long period, both to prepare and test specimens and the high-cost, resulting in a limited number of specimens. The heavy specimen creates another difficulty during set-up. Data accuracy depends on apparatus precision, laboratory conditions, and the technicians' expertise in experimenting. A finite element model was constructed to simulate a reinforced concrete element subject to high flexure and shear stresses induced by vertical and horizontal forces to overcome these constraints. The model can further be utilized to evaluate the effects of independent variables on the behavior of the member. The model was validated both numerically and experimentally to ensure accuracy and precision. The numerical validation was conducted through a sensitivity analyses process on the finesses of meshing and loading incrementation. At the same time, the load-deformation data and the crack propagation of identical laboratory-tested elements were utilized for validation of the experimental data. It was proven that the developed model predicts the behavior of the beam to a high degree of correctness. The model can further be used as a tool for analyses in the field.

scholarly journals Calculation of the crack resistance of reinforced concrete elements with allowance for the levels of normal crack formation

2018 ◽  
Vol 230 ◽  
pp. 02028 ◽  
Author(s):  
Vasyl Romashko ◽  
Olena Romashko
Keyword(s):  
Reinforced Concrete ◽  
Crack Resistance ◽  
Calculation Method ◽  
Solid Mechanics ◽  
Crack Formation ◽  
Crack Opening ◽  
Nonlinear Function ◽  
Experimental Investigations ◽  
Concrete Element ◽  
Concrete Elements

The separate experimental investigations results and the major drawbacks of existing methods of calculating the reinforced concrete elements crack resistance are considered in detail, taking into account the process of multilevel formation and crack opening. Based on the basic provisions of the deformation and strength model of concrete and reinforced concrete resistance, an engineering method for calculating the formation and disclosure of normal cracks in the reinforced concrete elements and structures at the operational stages of their deformation is proposed. It is implemented on the system of generally accepted static, geometric and physical relations of a deformed solid mechanics. The simplicity of the proposed calculation method is due to the use of the nonlinear function of the average stresses of the reinforcement bond with concrete on the sections of the reinforced concrete element between adjacent cracks. The main advantages of the developed calculation method in comparison with others are outlined.

Local Stress of Reinforced Concrete Elements

2016 ◽  
Vol 691 ◽  
pp. 398-407
Author(s):  
Iyad Abrahoim
Keyword(s):  
Reinforced Concrete ◽  
Compressive Load ◽  
Local Stress ◽  
Distribution Model ◽  
Distribution Area ◽  
Concrete Element ◽  
Lateral Tension ◽  
Tensile Forces ◽  
The Subject ◽  
Concrete Elements

The subject of the article is to apply the European standard when appraising the element’s bearing capacity in concentrated pressure under the anchoring slabs of pre-stressed reinforcement units. Method of concentrated pressure analysis. Method of performing expertise of the effects of lateral tensile forces. Local compressive load distribution model under the surface of the reinforced concrete element. Lateral tension in the local compressive load’s distribution area. Reinforcement against tearing of the surface of elements. Application in the expertise of the class of concrete in foundations.

Calculation Of Pressure Of Reinforcement Corrosion Products In Reinforced Concrete Element

2019 ◽  
pp. 65-69
Keyword(s):  
Reinforced Concrete ◽  
Protective Layer ◽  
Corrosion Products ◽  
Reinforcement Corrosion ◽  
Concrete Element ◽  
Geometric Nonlinearities ◽  
Good Convergence ◽  
Software Complex ◽  
Scientific Papers ◽  
Concrete Elements

The existing regulatory framework does not cover the calculation of reinforced concrete elements subjected to corrosion. The calculation of such elements is given in a number of scientific papers. The article deals with a particular problem of calculation-finding the pressure of corrosion products and calculation of detachment of the protective layer. To solve this problem, the polar-symmetric problem was solved and formulas for determining the pressure of corrosion products, stresses and displacements were obtained. The condition of destruction of samples is received based on the theory of strength of G. A. Geniev. The calculations carried out on the obtained dependences have good convergence with the calculations taking into account the physical and geometric nonlinearities, performed in the universal software complex ABAQUS. An engineering method for calculating the separation of the protective layer was developed. The possibility of experimental confirmation of the calculations, as well as the need for additional research in the field of corrosion damages is shown.

Evaluation Of The Effect Of Eccentricity Of Longitudinal Force On The Provision Of Bearing Capacity Of Compressed Concrete Elements

2019 ◽  
pp. 29-34 ◽  
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Coefficient Of Variation ◽  
Longitudinal Force ◽  
Deformation Model ◽  
Concrete Element ◽  
Average Value ◽  
Strength And Deformation ◽  
The Given ◽  
Concrete Elements

This work evaluates the influence of the eccentricity of longitudinal force on the provision of the bearing capacity of an eccentrically compressed reinforced concrete element in the normal section at different percentages of longitudinal reinforcement. The nonlinear deformation model was used for probabilistic calculations, which made it possible to take into account the influence of strength and deformation characteristics of concrete on the bearing capacity of the elements of reinforced concrete structures. The dependences of the relative average value of the maximum longitudinal force and the coefficient of variation for the given percent of reinforcement on the eccentricity of the longitudinal force are obtained. The significant influence of the value of the longitudinal force eccentricity on the coefficient of variation of the bearing capacity of the eccentrically compressed concrete element in the normal cross section is shown. It is noted that the revealed dependence of the bearing capacity of eccentrically compressed reinforced concrete elements on the eccentricity of the longitudinal force is not taken into account in the existing methods of calculation.

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