scholarly journals TO DETERMINATION OF THE CRACKING MOMENT FOR BENDING REINFORCED CONCRETE ELEMENTS WITH ACCOUNT OF PLASTIC DEFORMATIONS OF CONCRETE IN THE TENSION AREA

2018 ◽  
Vol 3 (3) ◽  
pp. 30-38
Author(s):  
О.В. Радайкин ◽  
Oleg Radaykin
Keyword(s):  
Reinforced Concrete ◽  
Deformation Model ◽  
Conventional Concrete ◽  
Class A ◽  
Standard Calculation ◽  
Plasticity Coefficient ◽  
Concrete Elements ◽  
Nonlinear Deformation Model ◽  
Good Agreement

At the standard calculation of the cracking moment for bending reinforced concrete elements the plasticity coefficient γ is normally used, which according to SP 63.13330.2012 is 35% less than in the old SNiP 2.03.01-84*. The question arises, what is the reason for such a noticeable difference and which of the methods gives more reliable results? This article seeks to answer this question. For this purpose the physical meaning of the coefficient γ was considered in detail, with the usage of a nonlinear deformation model of a normal section. A calculation formula for γ depending on an element’s reinforcement degree was obtained, which is valid for conventional concrete of B15-B35 class. A comparison of the calculated cracking moment according to the proposed method with experiments by the other authors was carried out. A good agreement of results was observed.

Perspectives of the Application for the Nonlinear Deformation Model in the Calculations of Reinforced Concrete Elements

2019 ◽  
Vol 974 ◽  
pp. 505-509
Author(s):  
D.S. Toshin
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Nonlinear Deformation ◽  
Structure Design ◽  
Deformation Model ◽  
Mathematical Writing ◽  
Flexible Form ◽  
Stiffness Characteristics ◽  
Concrete Elements ◽  
Nonlinear Deformation Model

The perspective directions of the calculation method applied application based on the nonlinear deformation model are presented. Some examples of the elements reinforced sections calculation applicability method with flexible, rigid steel reinforcement, composite reinforcement are given as well as the application of this method for the calculation of the uneven distribution of the strength and deformative characteristics of concrete and other damage to reinforced concrete structures; for the gain structure design, including the non-removing load; to assess the stiffness and carrying capacity of the elements with composite sections of various combinations of materials; for the calculation of the effect of repeated, alternating loads. To a large extent, the possibility of a broad application of the nonlinear deformation model is provided by the flexible form of mathematical writing of expressions for determining stiffness characteristics, which are transformed to the requirements of the solved problem.

Improvement Of Curvilinear Diagrams Of Concrete Deformation

2019 ◽  
pp. 99-104
Keyword(s):  
Reinforced Concrete ◽  
Peak Load ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Deformation Model ◽  
Reinforced Concrete Structures ◽  
Significant Difference ◽  
Deformation Diagrams

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.

scholarly journals Analyzing of Coatings on Steel - Reinforced Concrete Elements by Mobile NMR

2016 ◽  
Vol 62 (1) ◽  
pp. 65-82 ◽  
Author(s):  
J. Orlowsky
Keyword(s):  
Reinforced Concrete ◽  
Potential Effect ◽  
Building Site ◽  
Steel Reinforced Concrete ◽  
Mobile Nmr ◽  
The Individual ◽  
First Time ◽  
Concrete Elements ◽  
Non Destructive

Abstract A large number of infrastructural concrete buildings are protected against aggressive environments by coating systems. The functionality of these coating systems is mainly affected by the composition and thickness of the individual polymeric layers. For the first time ever, a mobile nuclear magnetic resonance (NMR) sensor allows a non-destructive determination of these important parameters on the building site. However, before this technique can be used on steel-reinforced concrete elements, the potential effect of the reinforcement on the measurement, i.e. the NMR signal, needs to be studied. The results show a shift of the NMR profile as well as an increase of the signals amplitude in the case of the reinforced samples, while calculating the thickness of concrete coating leading to identical results.

scholarly journals Strength and deformability of reinforced concrete elements under oblique eccentric short-term dynamic compression, tension and bending

2020 ◽  
Vol 164 ◽  
pp. 14008
Author(s):  
Dmitriy Sarkisov ◽  
Nikolay Gorlenko ◽  
Gleb Gorynin ◽  
Yuri Sarkisov ◽  
Gafurzhan Izmailov ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Crack Resistance ◽  
Dynamic Compression ◽  
Longitudinal Force ◽  
Research Data ◽  
Deformation Model ◽  
Relative Resistance ◽  
Short Term ◽  
Concrete Elements ◽  
Central Tension

The paper deals with research data of reinforced concrete rectangular and I-shaped cross-section elements, operating under oblique eccentric short-term dynamic compression, tension and bending. The method of reinforced concrete elements calculation using the theory of surfaces of relative resistance regarding strength and crack resistance is suggested. It is based on the deformation model with the use of real nonlinear diagrams of concrete and reinforcement. This method makes it possible to observe strength and crack resistance of reinforced concrete elements sections in the entire range of loadings from the central tension to axial compression. Experimental investigation of symmetrically reinforced concrete elements on oblique eccentric short-term dynamic compression, tension and oblique bending was carried out. Effect of longitudinal force level on strain distribution through the depth of section, bearing capacity, the failure scheme and other parameters are estimated.

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