scholarly journals Determination of loading modes for endurance tests of reinforced concrete sleepers on the basis of experimental measurement of their stress state under the conditions of the Test Loop at Shcherbinka

2021 ◽  
Vol 80 (3) ◽  
pp. 127-135
Author(s):  
O. A. Suslov ◽  
N. V. Ressina ◽  
A. V. Portnov ◽  
A. A. Novikov ◽  
V. A. Mariychuk
Keyword(s):  
Reinforced Concrete ◽  
Stress State ◽  
Strain State ◽  
Stress Strain ◽  
Bench Tests ◽  
Stress Strain State ◽  
Test Loop ◽  
Endurance Tests ◽  
Loading Modes ◽  
The Impact

The article considers the issue of changing the stressstrain state of reinforced concrete sleepers depending on the value of the axle loads and the requirements for the modes of its bench endurance tests. This issue is very relevant, since at present, in certain sections of the network (directions of the Eastern operational area), due to the high traffic density, the impact on the track increases and the axle load increases. Such a change entails the need to revise the requirements for the methods for determining and confirming the resource of all track elements, including the loading modes of reinforced concrete sleepers during its bench tests. To determine the influence of the axle load, measurements were made of the actual stress-strain state of reinforced concrete sleepers laid on the tangent section of the Test Loop of the JSC “VNIIZHT”. The loading was realized by a running train of 72 cars and a specially formed experimental coupler of a locomotive and three cars with an axle load of 23.5, 25 and 27 tf, respectively. Measurements made it possible to obtain the dependence of the change in stresses and deformations on the change in the axle load, as well as to reveal the rheological features of the interaction of reinforced concrete sleepers and the ballast layer. Obtained measurement results were used as basic stresses and strains for calculating loading modes in bench endurance tests. Purpose of the calculation is to achieve the maximum identity of the stress state when the sleepers are loaded on the bench with its stress state during real operation. In addition, experimental bench loading of a reinforced concrete sleeper was carried out, during which the modes obtained by the calculation were implemented and its stress-strain state was measured. Results of comparing the stress state of a reinforced concrete sleeper obtained during full-scale measurements on the way and during loading on the stand showed their identity, which confirmed the adequacy of the calculated loading modes. The final result of the work was the loading modes for bench tests of reinforced concrete sleepers, taking into account the influence of the axle load value.

scholarly journals Influence of the Cross-Sectional Shape of a Reinforced Bimodular Beam on the Stress-Strain State in a Transverse Impact

Buildings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 248
Author(s):  
Alexey Beskopylny ◽  
Elena Kadomtseva ◽  
Besarion Meskhi ◽  
Grigory Strelnikov ◽  
Oleg Polushkin
Keyword(s):  
Reinforced Concrete ◽  
Stress State ◽  
Cross Section ◽  
Strain State ◽  
Transverse Impact ◽  
Stress Strain ◽  
Cross Sectional ◽  
Stress Strain State ◽  
The Cross ◽  
The Impact

The paper considers the stress-strain state of a reinforced concrete beam, as a bimodular material, under the action of an impact. The behavior of bimodular concretes with different moduli of elasticity in tension and compression has not been studied enough. At the same time, taking into account the bimodularity of concrete makes it possible to design a more economical structure, especially for dynamic load. In this article, the impact is considered as an absolutely plastic impact of an absolutely rigid body on an elastic system. The stress state is investigated for beams of rectangular, T-section and I-sections, and is compared with and without the bimodularity of reinforced concrete. The analysis of the dependence of the stress state on the shape, cross-sectional dimensions, and the location of reinforcing bars in the compressed and tensioned zones was carried out for lightweight concrete (Et < Ec) and for heavy concrete (Et > Ec) under the action of shock load with and without regard to the mass of the beam. The numerical study shows that taking into account the mass of the beam upon impact significantly decreases the magnitude of the normal stresses in both the tensioned and compressed zones. Beams of rectangular cross-section have the highest load-bearing capacity when the cross-section height is equal for both light and heavy concrete. An increase in the size of the flange of the I-beam in the stretched zone leads to a sharp decrease in normal tensile stresses and a slight increase in normal compressive stresses. The proposed engineering method makes it possible to numerically study the effect on the stress-strain state of a beam under the action of a concentrated impact of various geometric characteristics of the cross-section, bimodularity of the material, size, number and location of reinforcement.

scholarly journals Transverse Impact on Rectangular Metal and Reinforced Concrete Beams Taking into Account Bimodularity of the Material

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1579 ◽  
Author(s):  
Alexey Beskopylny ◽  
Besarion Meskhi ◽  
Elena Kadomtseva ◽  
Grigory Strelnikov
Keyword(s):  
Reinforced Concrete ◽  
Strain State ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Normal Stresses ◽  
Reinforcing Bars ◽  
Stress Strain ◽  
Stress Strain State ◽  
Tension And Compression ◽  
The Impact

This article is devoted to the stress–strain state (SSS) study of metal and reinforced fiber-reinforced concrete beam under static and shock loading, depending on the bimodularity of the material, the mass of the beam, and the location of the reinforcing bars in zones under tension and compression. It is known that many materials have different tensile and compression properties, but in most cases, this is not taken into account. The calculations were carried out by using load-bearing metal beams made of silumin and steel and reinforced concrete beams under the action of a concentrated force applied in the middle of the span. The impact load is considered as the plastic action of an absolutely rigid body on the elastic system, taking into account the hypothesis of proportionality of the dynamic and static characteristics of the stress–strain state of the body. The dependences of the maximum dynamic normal stresses on the number of locations of reinforcing bars in zones under tension and compression, the bimodularity of the material, and the reduced mass of the beam are obtained. A numerical study of SSS for metal and concrete beams has shown that bimodularity allows the prediction of beam deflections and normal stresses more accurately.

scholarly journals THE STRENGTH OF REINFORCED CONCRETE BEAM ELEMENTS UNDER CYCLIC ALTERNATING LOADING AND LOW CYCLE LOAD OF CONSTANT SIGN

Vestnik MGSU ◽  
2015 ◽  
pp. 36-50 ◽  
Author(s):  
Yuliya Anatol'evna Semina
Keyword(s):  
Reinforced Concrete ◽  
Crack Resistance ◽  
Strain State ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Constant Sign ◽  
Stress Strain ◽  
Beam Elements ◽  
Stress Strain State ◽  
The Impact

The behavior of reinforced concrete elements under some types of cyclic loads is described in the paper. The main aim of the investigations is research of the stress-strain state and strength of the inclined sections of reinforced concrete beam elements in conditions of systemic impact of constructive factors and the factor of external influence. To spotlight the problem of cyclic loadings three series of tests were conducted by the author. Firstly, the analysis of the tests showed that especially cyclic alternating loading reduces the bearing capacity of reinforced concrete beams and their crack resistance by 20 % due to the fatigue of concrete and reinforcement. Thus the change of load sign creates serious changes of stress-strain state of reinforced concrete beam elements. Low cycle loads of constant sign effect the behavior of the constructions not so adversely. Secondly, based on the experimental data mathematical models of elements’ strength were obtained. These models allow evaluating the impact of each factor on the output parameter not only separately, but also in interaction with each other. Furthermore, the material spotlighted by the author describes stress-strain state of the investigated elements, cracking mechanism, changes of deflection values, the influence of mode cyclic loading during the tests. Since the data on the subject are useful and important to building practice, the ultimate aim of the tests will be working out for improvement of nonlinear calculation models of span reinforced concrete constructions taking into account the impact of these loads, and also there will be the development of engineering calculation techniques of their strength, crack resistance and deformability.

scholarly journals DYNAMIC STRENGTH CONDITION OF CONCRETE UNDER PLANE STRESS STATE

2019 ◽  
Vol 21 (4) ◽  
pp. 138-145
Author(s):  
Z. R. Galyautdinov
Keyword(s):  
Reinforced Concrete ◽  
Stress State ◽  
Plane Stress ◽  
Strain State ◽  
Dynamic Deformation ◽  
Dynamic Strength ◽  
Strength Condition ◽  
Stress Strain ◽  
Stress Strain State ◽  
Wide Range

Modern calculation models must take into account the dynamic deformation of reinforced concrete. Currently, the main regularities of nonlinear dynamic deformation of reinforced concrete under uniaxial stress state are theoretically analyzed in detail along with a wide range of experimental studies. Properties of concrete under plane stress -strain state and dynamic loading are examined to a lesser extent. This paper proposes the dynamic strength condition for the concrete strength which allows for changing the strain -hardening coefficient of concrete depending on the type of stress -strain state, the ratio of the primary stresses and the deformation rate.

scholarly journals Concrete-faced rockfill dams: experience in study of stress-strain state

Vestnik MGSU ◽  
2019 ◽  
pp. 207-224 ◽  
Author(s):  
Vladislav B. Soroka ◽  
Mikhail P. Sainov ◽  
Denis V. Korolev
Keyword(s):  
Numerical Modeling ◽  
Reinforced Concrete ◽  
Strain State ◽  
Stress Strain ◽  
Linear Character ◽  
Stress Strain State ◽  
Operation Conditions ◽  
Numerical Studies ◽  
Deformation Properties ◽  
The Impact

Introduction. At present the urgent problem in hydraulic construction is establishing the causes of crack formation in seepage-control reinforced concrete faces at a number of rockfill dams. For solving this problem the studies are conducted of stress-strain state (SSS) of concrete-faced rockfill dams which are fulfilled by different methods. Materials and methods. Gives a review and analysis of the results of studies of stress-strain state of concrete-faced rockfill dams (CFRD) fulfilled by different authors over the last 15 years. The results of analytical, experimental and numerical studies are considered. Descriptions are given of the models used for simulation of non-linear character of rockfill deformation at numerical modeling of dam SSS. Results. Analysis showed that solving the problem of CFRD SSS causes a number of methodological difficulties. At present the only method permitting study of CFRD SSS is numerical modeling. The rest methods do not permit considering the impact of important factors on SSS. Large complications are caused by scarce knowledge of rockfill deformation properties in real dams. Conclusions. It was revealed that at present SSS of reinforced concrete faces has been studied insufficiently. The results of conducted studies do not give full and adequate understanding about operation conditions of reinforced concrete faces. Impact of various factors on the face SSS has not been studied. Besides, there are contradictions in the results of studies obtained by different authors. Differences in the results are based on objective and subjective reasons. A considerable obstruction for numerical studies is complicated modeling of rigid thin-walled reinforced concrete face behavior at large deformations inherent to rockfill. The obtained results of studies often do not permit conducting full analysis of SSS of concrete-faced rockfill dams.

scholarly journals A method for assessing the stress-strain state of reinforced concrete structures

2019 ◽  
Vol 91 ◽  
pp. 02046 ◽  
Author(s):  
Andrew Varlamov ◽  
Vladimir Rimshin ◽  
Sergey Tverskoi
Keyword(s):  
Reinforced Concrete ◽  
Stress State ◽  
Strain State ◽  
Concrete Structures ◽  
Residential Building ◽  
Small Sample ◽  
Reinforced Concrete Structures ◽  
Stress Strain ◽  
Stress Strain State ◽  
Industrial Buildings

The article analyses the modern methods of estimation of stress-strain state of reinforced concrete structures. The result of the analysis is a new method for estimating the stress-strain state of reinforced concrete structures. The method is based on extracting a small sample of concrete from the array. The article describes the method of execution of works, the method of calculating the stresses. Previously, the method was investigated under laboratory conditions. The results are presented in graphs and tables. The research was conducted to assess the stress state of existing concrete structures. As the objects of research, two industrial buildings of 1933 and 1941 construction years were taken. An assessment of a stress state of a panel residential building was held. The measurement results were analyzed. The method for determining the stresses in reinforced concrete buildings and structures is recommended.

scholarly journals Диагностика разрушения армированного бетона в условиях изгиба по параметрам электрического отклика на ударное воздействие

2019 ◽  
Vol 89 (1) ◽  
pp. 99
Author(s):  
Т.В. Фурса ◽  
Д.Д. Данн ◽  
М.В. Петров ◽  
А.Н. Соколовский
Keyword(s):  
Reinforced Concrete ◽  
External Load ◽  
Strain State ◽  
Electric Response ◽  
Stress Strain ◽  
Impact Action ◽  
Stress Strain State ◽  
Four Point Bending ◽  
Reinforced Beams ◽  
The Impact

AbstractRegularities of changes in the stress-strain state of reinforced concrete in the process of testing for four-point bending have been studied. The change in characteristics of the electric response to an impact action in the process of a sequential increase in the external load has been analyzed. Regularities in the relation between parameters of the electric response to the impact action and stages of the stress-strain state of reinforced beams in the process of bending have been revealed. Criteria of determining stages of reinforced beam destruction by parameters of the electric response are proposed.

Stress-strain state of corrosion-damaged reinforced concrete elements under dynamic loading

2019 ◽  
pp. 19-26
Keyword(s):  
Reinforced Concrete ◽  
Strain State ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Stress Strain ◽  
Static Loads ◽  
Software Complex ◽  
Stress Strain State ◽  
The Impact ◽  
Concrete Elements

The solution of problems of survivability of reinforced concrete elements at beyond design impacts caused by simultaneous manifestation of power and environmental factors is necessary in modern realities. The impact of external aggressive environments, the operation of buildings without timely repairs is the cause of corrosion processes in reinforced concrete elements, which leads to a decrease in their bearing capacity and, as a consequence, reduction in the life of buildings. Currently, one of the urgent problems is the actual work of corrosion-damaged reinforced concrete elements under the impact of dynamic and static loads. The bendable reinforced concrete beam locally damaged in the compressed part of the cross-section is considered. Using modern computing software complex, it was carried out the comparative evaluation of the stress-strain state of an undamaged and corrosion-damaged reinforced concrete elements under dynamic and static loading. The influence of the weakened by corrosion concrete part of the compressed area on the redistribution of stresses in the section is analyzed.

Investigation of the Stress-Strain State of a Steel Column Base Connection for Seismic Regions

2022 ◽  
Vol 906 ◽  
pp. 93-98
Author(s):  
Tigran Dadayan ◽  
Lusine Karapetyan
Keyword(s):  
Reinforced Concrete ◽  
Strain State ◽  
Main Type ◽  
Industrial Building ◽  
Stress Strain ◽  
Concrete Foundation ◽  
Stress Strain State ◽  
Steel Base ◽  
Steel Column ◽  
Seismic Regions

Currently, the main type of connection between a steel column and a reinforced concrete foundation is a steel base, which is often economically unprofitable due to its size, number or diameter of anchor bolts. Not only in Armenia, but also in most countries, a steel base is the main type of connection between a steel column and a reinforced concrete foundation. The usage of other types of connections is associated with both new calculation methods and technological problems. The possibility of computation and design of the connection of a steel column with a reinforced concrete foundation in seismically active regions using shear studs is considered in this work, a reinforced concrete section with longitudinal reinforcement is used for this type of connection which ensures a smooth transfer of forces from the column to the foundation. Based on the example of the connection of a single-story industrial building column shows the change in the stress-strain state of the connection under axial force and bending moments for seismic regions. Not only the feature and construction technology of the connection considered in the work, but also proposes a calculation method with future possibility of its subsequent inclusion in the building codes of the Republic of Armenia.

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