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 STUDIES OF THE STRESS-STRAIN STATE OF REINFORCED CONCRETE BEAMS REINFORCED WITH CARBON FIBER

2021 ◽  
Vol 82 (4) ◽  
pp. 101-110
Author(s):  
I.S. Bondar ◽  
◽  
Al Dulaimi Salman Dawood Salman ◽  
D.T. Aldekeyeva ◽  
R.S. Imambaeva ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Strain State ◽  
Concrete Beams ◽  
Field Studies ◽  
Reinforced Concrete Beams ◽  
Stress Strain ◽  
Reinforced Plastics ◽  
Stress Strain State ◽  
Numerical Studies

The article examines field studies of reinforced concrete beams, fracture schemes, and the nature of the formation, development of cracks in reinforced concrete elements. Modeling the stress-strain state of reinforced concrete beams in the ANSYS software and computational complex, comparing the results of field and numerical studies. A method of finite element modeling of beams reinforced with fiber plastics (carbon fiber reinforced plastics) is proposed. A comparison of fracturing schemes obtained as a result of numerical simulation is presented.

scholarly journals Impact of rockfill dam structure heterogeneity on reinforced concrete face stress-strain state

2019 ◽  
pp. 5-5 ◽  
Author(s):  
Mikhail Sainov ◽  
Igor Egorov ◽  
Konstantin Pak
Keyword(s):  
Reinforced Concrete ◽  
Strain State ◽  
Longitudinal Force ◽  
Heterogeneous Structure ◽  
Stress Strain ◽  
Stress Strain State ◽  
Rockfill Dam ◽  
Deformation Properties ◽  
The Face ◽  
Concrete Face

Introduction. One of the main principles in designing modern ultra-high rockfill dams with reinforced concrete face is the principle of zoning rockfill of various quality in the dam body. It envisages that rockfill in the shell upper part should be compacted very carefully in order to minimize to the maximum the deflections of the reinforced concrete face. In the shell lower part it is allowed placing heterogeneous rockfill with less degree of compaction. Analysis of the results of field observations over settlements of the already constructed dams shows that this pattern of zoning may lead to considerable irregularity in distribution of rockfill deformation moduli between the upstream and the downstream parts of the dam. Numerical modeling of the existing Aguamilpa dam carried out by use arlier showed that this effect may be caused by unfavorable stress-strain state of the reinforced concrete face threatening with crack formation. Were come ended using dams of homogenous structure. However, this conclusion caused doubts of some experts. More detailed studies who see results are described in this article were conducted in order to confirm or disprove this conclusion. Materials and methods. The studies were conducted by finite element method on the example of 100 m high rockfill dam. Different alternatives of rockfill deformation properties in the shell upstream and downstream parts were considered. Results. Analysis of the results of studies confirmed the conclusions made earlier about the features of the rockfill dam reinforced concrete face stress-strain state. It was revealed that increase of rockfill deformation in the dam shell downstream part leads to appearance of additional tensile longitudinal force in the face. It increases the risk of appearance of through transversal cracks in the face. However, the heterogeneous structure of the dam shell may not have a decisive impact on stress values because the value of bending moment plays a great role. Conclusions. The results of the fulfilled study as well as modern dam construction practice show the necessity of modifying the traditional pattern of rockfill zoning in the dam body. It is necessary to provide decrease of differences in rockfill deformation of the upstream and downstream parts of the dam.

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 Role of transverse joints in regulation of the reinforced concrete face stress-strain state

Vestnik MGSU ◽  
2018 ◽  
pp. 1533-1545
Author(s):  
Aleksei A. Podvysotckii ◽  
Mikhail P. Sainov ◽  
Vladislav B. Soroka ◽  
Roman V. Lukichev
Keyword(s):  
Numerical Modeling ◽  
Reinforced Concrete ◽  
Strain State ◽  
Tensile Force ◽  
Bending Moments ◽  
Stress Strain ◽  
Tensile Stresses ◽  
Stress Strain State ◽  
Transverse Joint ◽  
The Face

Introduction. Deals with the results of studying effectiveness of arranging transverse joints in the face as the means of regulation of its stress-strain state. At present reinforced concrete faces are constructed without being cut height-wise and transverse joints may be arranged only at the end of the dam construction stages. This is validated by the fact that experience in construction of flexible (discontinuous) faces has not demonstrated the required level of safety of this structural design. However, in the dams of the up-to-date structural designs, maintaining the face integrity is not guaranteed: cracks appeared in reinforced concrete faces at a number of high dams. Formation of cracks in faces should be attributed to presence of tensile stresses, whose values exceed concrete tensile strength. To prevent seal failure of the seepage-control element it is feasible to provide arrangement of the transverse joint in the face section where tensile stresses may be expected. Materials and methods. The studies were conducted on the example of a 100 m high dam with the aid of numerical modeling. Rockfill was considered as a lineally deformed material, but computations were conducted for a wide range of the soil linear deformation modulus: from 60 to 480 МPа. Steel reinforcement was considered in the face. Transverse joints were modelled with the aid of contact finite elements. Results. By the results of numerical modeling the tensile stresses appear in the uncut face due to bending deformations and deformations of longitudinal extension. The most hazardous is the face lower section. At this section the longitudinal tensile force and considerable moment are acting. Transverse joints are feasible to be arranged in this particular section of the face. Conclusion. It was revealed that the main positive effect of the transverse joint arrangement is in decreasing the value of longitudinal tensile force perceived by the face. Impact of the transverse joint on bending moments has a local effect and covers the section of the limited length. Moreover, at arranging joints the values of bending moments may increase. We may recommend arrangement of a transverse joint in the face which is parallel to the perimeter joints only in the face lower part which is subject to longitudinal deformation.

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.

Results of Numerical Modeling the Stress-Strain State of Damaged Reinforced Concrete Columns in the Middle Row of the Industrial Building

2019 ◽  
Vol 968 ◽  
pp. 342-347
Author(s):  
Viktor Dariienko ◽  
Dmytro Artemenko ◽  
Olexandr Lizunkov ◽  
Oleh Plotnikov
Keyword(s):  
Numerical Modeling ◽  
Reinforced Concrete ◽  
Strain State ◽  
Concrete Columns ◽  
Industrial Building ◽  
Reinforced Concrete Column ◽  
Stress Strain ◽  
Reinforced Concrete Columns ◽  
Stress Strain State ◽  
Concrete Body

The article is devoted to the investigation of the influence of columns’ concrete body destruction size on the bearing capacity of building structures. The joint spatial work of steel strengthening structures with reinforced concrete constructions is investigated. The results of numerical modeling the stress-strain state of damaged reinforced concrete columns in the middle row of the industrial building are presented. The numerical modeling was executed in the system NASTRAN. It was carried out the numerical calculation of reinforced concrete column in the middle row without damages. Then it was modeled the column damage in form of a "downed" concrete angle to a depth of 50, 100 and 200 mm and denudation of bearing longitudinal armature at length of 1000 mm from supporting part of the column. In this case two separate models were investigated - with the location of damage from the compressed or extended side of the column. The conclusions about feasibility of columns strengthening by steel clip are made.

scholarly journals Numerical modeling of the stress-strain state of peripheral massif in the vicinity of mine workings

2021 ◽  
Vol 330 ◽  
pp. 01009
Author(s):  
Anastasiya Nikitina ◽  
Dmitriy Borzykh ◽  
Sergey Rib ◽  
Aleksandra Lesnykh ◽  
Tonglin Zhao
Keyword(s):  
Numerical Modeling ◽  
Mine Working ◽  
Strain State ◽  
Stress Strain ◽  
Roof Bolting ◽  
Stress Strain State ◽  
Numerical Studies ◽  
Preparatory Working ◽  
Mine Workings ◽  
Maximum Exposure

In the process of numerical studies, the stress-strain state of the rock massif around the mine working driven at a depth of 600 m was determined. The article presents the analysis of the distribution of total vertical and horizontal stresses isolines in the working roof, as well as the ratio of the residual strength of rocks to the initial. The influence of the roof bolting on the displacement of working contour was established. Dangerous zones in the near-contour rocks of preparatory working were identified. The maximum exposure area of unsecured part of the roof during driving the workings in seam 3-3a was established.

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.

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.

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