scholarly journals Stress-strain state of reinforced concrete structures of the LN-1 and LN-2 retaining walls of Zagorskaya PSPP taking into account the opening of interblock joints and the formation of secondary cracks

2021 ◽  
Vol 17 (4) ◽  
pp. 324-334
Author(s):  
Nartmir V. Khanov ◽  
Fedor A. Pashchenko
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Strain State ◽  
Retaining Walls ◽  
Transverse Reinforcement ◽  
Reinforced Concrete Structures ◽  
Finite Element Models ◽  
Computational Studies ◽  
Stress Strain ◽  
Stress Strain State

Relevance. The lower retaining walls of the water intake of the Zagorskaya PSPP perform the important function of protecting the pressure water conduits from the collapse of the soil massif. Two of them (LN-2 and LN-3) were reinforced with anchor rods. Considering the long period of operation (more than 25 years), certain deviations in the work during examinations and field observations were revealed. So, on the front face of the walls, extended horizontal cracks were recorded (opening of horizontal interblock joints and the emergence of secondary oblique cracks on the front surface of the walls). To carry out computational studies of the stress-strain state of the downstream retaining walls was required. The purpose of the work was to determine the stress-strain state of the lower retaining walls of the water intake of the Zagorskaya PSPP taking into account the opening of interblock joints and the formation of secondary oblique cracks. Methods. Computational studies of the stress-strain state of retaining walls were carried out within the framework of the method of numerical modeling of reinforced concrete structures of hydraulic structures based on finite element models. In finite element models, structural features of retaining walls were reproduced, including anchor rods, horizontal interblock joints, actual reinforcement, secondary oblique cracks. Results. The stress-strain state of the retaining walls was obtained. The stresses in the longitudinal and transverse reinforcement were determined, including when the structure was changed due to anchor rods. In horizontally transverse reinforcement, tensile stresses exceeding the yield point are recorded. It took the development of measures to strengthen the lower retaining walls.

scholarly journals Analysis the effects of lightweight concrete in the middle layer of multi-layered reinforced concrete structures on the stress-strain state using the finite element method

2018 ◽  
Vol 196 ◽  
pp. 02022 ◽  
Author(s):  
Elena Korol ◽  
Vu Dinh Tho ◽  
Nguyen Huy Hoang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Strain State ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
The Finite Element Method ◽  
Stress Strain ◽  
Stress Strain State ◽  
Wide Range

The development of methods for the calculating reinforced concrete structures covers a wide range of issues, including the expansion of the application of new innovative materials such as concrete and reinforcement. For usage in the practice of modern construction of multilayer structures made of concrete with different physic-mechanical characteristics, it is compulsory to conduct numerical studies of the stress-strain state of these structures under different types of loading. This article presents an analysis of the influence of the relations between the initial elastic modulus of the outer and middle layers for the stress-strain state and the deflection of three-layer reinforced concrete structures using the finite element method in the program ANSYS Mechanical. Numerical modeling allows comparing the obtained results and building theoretical dependences in a wide range of specified parameters for the construction of sections of multilayer reinforced concrete elements. The obtained scientific results enable to determine rational parameters for modeling various structural solutions of multilayer reinforced concrete structures. This would limit the number of actual test samples, increasing the efficiency of the experiment.

scholarly journals Elaboration of testing technique of flat slabs on punching shear strength using finite element modeling

2018 ◽  
Vol 196 ◽  
pp. 02048
Author(s):  
Valery Filatov ◽  
Zulfat Galyautdinov ◽  
Alexander Suvorov
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Cross Section ◽  
Strain State ◽  
Concrete Slabs ◽  
Finite Element Models ◽  
Bending Moments ◽  
Stress Strain ◽  
Stress Strain State ◽  
Reinforced Concrete Slabs

The results of researches on finite-element models of stress-strain state of flat reinforced concrete slabs of beamless frame under punching by columns of square and rectangular cross-section are presented. The purpose of the study was to develop a technique for testing samples plates for punching in the presence of bending moments in a column. The results of the study of deflections of reinforced concrete slabs, the distribution of bending moments in the punching zone of the plate under various loading schemes are presented. Variable parameter was the ratio of the sides of the column cross-section. Comparative analysis of studies results on finite element models has made it possible to choose the optimal variant of applying the load to the test samples, depending on the aspect ratio of rectangular section of column. Results of the conducted research will allow simulating the stress-strain state in the punching zone of natural reinforced concrete slabs of monolithic beamless frame during the test of samples.

scholarly journals Experimental-theoretical studies of hydrotechnical angular-type retaining walls

2021 ◽  
Vol 17 (1) ◽  
pp. 82-91
Author(s):  
Fedor A. Pashchenko
Keyword(s):  
Reinforced Concrete ◽  
Strain State ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Retaining Walls ◽  
Variable Load ◽  
Reinforced Concrete Structures ◽  
Stress Strain ◽  
Term Operation ◽  
Stress Strain State

Relevance. Retaining walls are common structures that are part of waterworks. They have the characteristic features of hydraulic structures, such as large dimensions, low percentages of reinforcement (up to 1.0%), horizontal interblock joints. The listed features determine the nature of the work and the stress-strain state of the retaining walls. The main loads on the rear faces of the retaining walls are loads from the action of the backfill soil. The incomplete consideration of the design features and the nature of the loads action in the design of a number of retaining walls that are in the stage of long-term operation has caused the need to strengthen them. One of the reinforcement methods was to install reinforcement rods in drilled inclined holes in the zones of horizontal interblock joints. It was necessary to conduct experimental studies of reinforced concrete retaining walls under the action of various loads, in particular conside- ring the reinforcement by inclined rods. The aim of the experimental research was to study the effect of variable load on the stress-strain state of these structures, among others with due regard to inclined reinforcement installed in the zones of horizontal interblock joints. When solving the set tasks, proven experimental methods of researching reinforced concrete structures of hydrotechnical structures were used. Results. Experimental data from the study of models of retaining walls, including those with reinforcement by inclined reinforcement, at different locations of the resultant load on rear faces of models were obtained. An experimental substantiation of the reinforcement of reinforced concrete structures of retaining walls with an inclined reinforcement crossing horizontal construction joints has been carried out.

scholarly journals REGULARITIES OF THE LINING STRESS-STRAIN STATE DURING OF THE PYLON METRO STATION CONSTRUCTION

2021 ◽  
pp. 19-27
Author(s):  
D. O. BANNIKOV ◽  
V. P. KUPRII ◽  
D. YU. VOTCHENKO
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Finite Elements ◽  
Strain State ◽  
Finite Element Models ◽  
Bending Moments ◽  
Stress Strain ◽  
Normal Forces ◽  
Stress Strain State ◽  
Station Structure

Purpose. Perform numerical analysis of the station structure. Take into account in the process of mathematical modeling the process of construction of station tunnels of a three-vaulted station. Obtain the regularities of the stress-strain state of the linings, which is influenced by the processes of soil excavation and lining construction. Methodology. To achieve this goal, a series of numerical calculations of models of the deep contour interval metro pylon station was performed. Three finite-element models have been developed, which reflect the stages of construction of a three-vaulted pylon station. Numerical analysis was performed on the basis of the finite element method, implemented in the calculation complex Lira for Windows. Modeling of the stress-strain state of the station tunnel linings and the soil massif was performed using rectangular, universal quadrangular and triangular finite elements, which take into account the special properties of the soil massif. Station tunnel linings are modeled by means of rod finite elements. Findings. Isofields of the stress-strain state in finite-element models reflecting the stages of construction are obtained. The vertical displacements and horizontal stresses that are characteristic of a three-vaulted pylon station are analyzed. The analysis of horizontal stresses proved that at the stage of opening of the middle tunnel the scheme of pylon operation is rather disadvantageous. The analysis of bending moments and normal forces was also carried out and the asymmetry of their distribution was noted. Originality. Based on the obtained patterns of distribution of stress-strain state and force factors, it is proved that numerical analysis of the station structure during construction is necessary to take measures to prevent or reduce deformation of frames that are in unfavorable conditions. Practical value. In the course of research, the regularities of changes in stresses, displacements, bending moments and normal forces in the models of the pylon station, which reflect the sequence of its construction, were obtained.

scholarly journals Critical stresses arising in the destruction of a floating reinforced concrete pontoon

2021 ◽  
Vol 264 ◽  
pp. 03032
Author(s):  
Dina Morozova ◽  
Dmitrii Malakhov
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Strain State ◽  
Wind Wave ◽  
Computer Models ◽  
Stress Strain ◽  
Stress Strain State ◽  
Critical Stresses ◽  
Extreme Wind ◽  
Wave Effects

The article discusses the stress-strain state of a reinforced concrete floating pontoon caused by critical stresses before its destruction. The investigation was motivated by the destruction of the pontoon, which occurred under extreme wind and wave impacts. A method for determining wind, wave and current loads is presented. The investigation was carried out on finite element computer models. As a result of the investigation, critical efforts and stresses were obtained, causing the destruction of the pontoon. The main conclusion of the conducted investigation is the possibility of using a floating reinforced concrete pontoon in waters with limited values of wind, wave effects and loads from the current.

scholarly journals ANALYSIS OF FEATURES OF APPLIED SOFTWARE “LIRA” IN CALCULATIONS OF NON-CIRCULAR TUNNEL LININGS

2019 ◽  
pp. 41-50
Author(s):  
V. P. KUPRIY ◽  
O. L. TIUTKIN ◽  
P. YE. ZAKHARCHENKO
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Finite Element Model ◽  
Software Package ◽  
Strain State ◽  
Element Model ◽  
Finite Element Models ◽  
Stress Strain ◽  
Stress Strain State ◽  
The Finite Element Model

Purpose. The article examines the effect on the stress-strain state of the parameters of the finite-element model created in the “Lira” software package in a numerical analysis of non-circular outlined tunnels. Methodology To achieve this goal, the authors developed finite element models of the calotte part of the mine during the construction of a double track railway tunnel using “Lira” software. In each of the models in the “Lira” software package, the interaction zone with temporary fastening was sampled in a specific way. After creation of models, their numerical analysis with the detailed research of his results was conducted. Findings. In the finite element models, the values of deformations and stresses in the horizontal and vertical axes, as well as the maximum values of the moments and longitudinal forces in the temporary fastening were obtained. A comparative analysis of the obtained values of the components of the stress-strain state with a change in the parameters of the finite element model was carried out. The graphs of the laws of these results from the discretization features of the two models were plotted. The third finite element model with a radial meshing in the zone of interaction of temporary support with the surrounding soil massif was investigated. Originality It has been established that in the numerical analysis of the SSS of a tunnel lining of a non-circular outline, its results substantially depend on the shape, size and configuration of the applied finite elements, on the size of the computational area of the soil massif, and also on the conditions for taking into account the actual (elastic or plastic) behavior of the soil massif.  Practical value. The features of discretization and the required dimensions of the computational area of the soil massif were determined when modeling the “lining – soil massif” system, which provide sufficient accuracy for calculating the parameters of the stress-strain state of the lining.

scholarly journals ESTIMATED JUSTIFICATION OF TECHNICAL DECISION ON STRENGTHENING REINFORCED CONCRETE MACHINE HALL FLOOR

2019 ◽  
Author(s):  
Oleg D. Rubin ◽  
Anton S. Antonov ◽  
Sergey E. Lisichkin ◽  
Igor V. Baklykov ◽  
Nikolay V. Bekin ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Strain State ◽  
Actual State ◽  
Computational Studies ◽  
Lower Edge ◽  
Stress Strain ◽  
Concrete Floor ◽  
Stress Strain State ◽  
External Reinforcement ◽  
Machine Hall

Introduction. In connection with the long-term operation of hydraulic structures (HPP), the installation of significant temporary loads, the presence of alternating effects on individual structural elements, it is possible to reduce the carrying capacity and strength of reinforced concrete structures. One of the most crucial elements is the reinforced concrete overlap of the machine hall, the work presents field and design studies, a proposal to strengthen the structures with external reinforcement. Materials and methods. The scientific and technical documentation was analyzed, instrumental studies and visual inspections of the state of the structures were carried out, and a 3D mathematical model was developed based on the finite element method. Multivariate non-linear computational studies of the actual stress-strain state of structures have been carried out. Results. Conducted visual and instrumental examination showed the presence of cracking on the lower edge of the reinforced concrete floor of the machine room. The simulation of the actual state of the structures has been carried out; according to the results of calculations, a schematic diagram of the gain of structures has been proposed. Conclusions. As a result of computational studies of stress-strain state, the occurrence of cracks on the lower edge of reinforced concrete floor of the machine hall was confirmed. When applying temporary technological loads to overlap, it is possible to achieve the yield strength of the reinforcement in certain zones. In order to ensure further safe operation of the structures, a conceptual amplification scheme based on the results of stress-strain state calculations has been proposed.

scholarly journals Field tests and numerical experiments of composite reinforced concrete floor

Vestnik MGSU ◽  
2015 ◽  
pp. 58-67
Author(s):  
Farit Sakhapovich Zamaliev ◽  
Vadim Andreevich Morozov
Keyword(s):  
Reinforced Concrete ◽  
Numerical Experiments ◽  
Strain State ◽  
Concrete Structures ◽  
Field Tests ◽  
Experimental Investigations ◽  
Reinforced Concrete Structures ◽  
Stress Strain ◽  
Concrete Floor ◽  
Stress Strain State

In the recent years there appeared a tendency of widening the use of composite reinforced concrete structures in Russian construction practice, which keeps current the further investigations of their stress-strain state. In order to estimate the stress-strain state of composite reinforced concrete structures different methods are used: both analytical and experimental. In spite of material and labour costs field tests give the most correct indexes of the behavior of structures in actual operating conditions. The experimental investigations of composite reinforced concrete floors of civil buildings having considerable slenderness allow exploring new qualitative data of their stress-strain state. The authors offer the analysis of experimental investigations of composite reinforced concrete structures, in particular, composite reinforced concrete floor. They described geometrical and physical parameters of a test piece, the methods of measurements and tests, the experiment’s results are analyzed. The charts of flexure, stress blocks and distribution of moments are offered. The authors also give the results of numerical experiments and comparisons of stress-strain state of composite reinforced concrete floor with the results of field tests and their analysis.

scholarly journals Load simulation of a base station chassis of the mobile transport and overloading rope complex

2021 ◽  
Vol 7 (2) ◽  
pp. 166-175
Author(s):  
V.I. Tarichko ◽  
◽  
P.I. Shalupina ◽  
Keyword(s):  
Finite Element ◽  
Strain State ◽  
Metal Structure ◽  
Base Station ◽  
Finite Element Models ◽  
Stress Strain ◽  
Grid Model ◽  
Stress Strain State ◽  
Load Simulation

The article deals with the issues of modeling the stress-strain state of a chassis designed to accommodate the equipment of a mobile transport and overloading rope complex. The main computational cases are determined. Geometric and computational finite element models are constructed, taking into account the features of the metal structure and suspension elements. The method of gluing elements of the grid model is applied. On the basis of the performed calculations, conclusions are drawn about the compliance of the developed structure with the requirements of strength and rigidity.

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