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 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 Experimental research of punching shear mechanism of reinforcing concrete slab

2019 ◽  
Vol 97 ◽  
pp. 04032
Author(s):  
Nikolay Trekin ◽  
Dmitrii Pekin
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Experimental Research ◽  
Strain State ◽  
Concrete Slab ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Stress Strain ◽  
Stress Strain State ◽  
Reinforced Concrete Slabs

The analysis of various regulatory methods for calculating reinforced concrete slabs for pushing and comparing with experiment results is made. The tested sample, measuring equipment and test bench are described. Sizes and materials for experimental prototype were chosen by existing beamless and capless slabs of monolithic reinforced concrete superstructures with column grid from 8×8 to 9×9 m. Experimental research results of reinforcing concrete plate structure are presented for study purpose of stress-strain state when punching shear collapse occurring. Various aspects and observations obtained during the test are given. The comparison of the tested slab fragment with the complete response of slab structure is performed. Analysis of tested sample stress-strain state and punching bearing capacity calculations results in according to existing regular standards were made. Main criterias of punching shear collapse were determined and new procedure for punching calculation of RC concrete slabs was offered basing on significantly new approach in punching bearing capacity defining.

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 Deformations of R.C.Circular Slabs in Fire Condition

2018 ◽  
Vol 4 (4) ◽  
pp. 712 ◽  
Author(s):  
Abdelraouf Tawfik Kassem
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Slenderness Ratio ◽  
High Surface ◽  
High Surface Area ◽  
Concrete Slabs ◽  
Finite Element Models ◽  
Reinforced Concrete Slabs ◽  
Fire Condition ◽  
In Fire

Reinforced concrete slabs are elements in direct contact with superimposed loads, having high surface area and small thickness. Such a condition makes slabs highly vulnerable to fire conditions. Fire results in exaggerated deformations in reinforced concrete slabs, as a result of material deterioration and thermal induced stresses. The main objective of this paper is to deeply investigate how circular R.C. slabs, of different configurations, behave in fire condition. That objective has been achieved through finite element modelling. Thermal-structural finite element models have been prepared, using "Ansys". Finite element models used solid elements to model both thermal and structural slab behaviour. Structural loads had been applied, representing slab operational loads, then thermal loads were applied in accordance with ISO 843 fire curve. Outputs in the form of deflection profile and edge rotation have been extracted out of the models to present slab deformations. A parametric study has been conducted to figure out the significance of various parameters such as; slab depth, slenderness ratio, load ratio, and opening size; regarding slab deformations. It was found that deformational behaviour differs significantly for slabs of thickness equal or below 100 mm, than slabs of thickness equal or above 200 mm. On the other hand considerable changes in slabs behaviour take place after 30 minutes of fire exposure for slabs of thickness equals or below 100 mm, while such changes delay till 60 minutes for slabs of thickness equals or above 200 mm.

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 Static analysis of a reinforced bimodulus beam on elastic foundation

2018 ◽  
Vol 196 ◽  
pp. 02003 ◽  
Author(s):  
Alexey Beskopylny ◽  
Elena Kadomtseva ◽  
Grigory Strelnikov
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Strain State ◽  
Building Materials ◽  
Elastic Base ◽  
Reinforced Concrete Beams ◽  
Building Structures ◽  
Maximum Deflection ◽  
Stress Strain ◽  
Stress Strain State

The work considers a reinforced concrete beam made of bimodule material on an elastic Winkler base. The influence of the number of reinforcing bars located in the stretched zone on the maximum normal stress and the maximum deflection is numerically investigated. The choice of the cross-section dimensions, such as the width and thickness of the flanges, the height of the beam, causes particular difficulties and is limited by the need to determine specific ratios of I-beam sizes. Numerical investigation allows analyzing the influence of the width of the I-beam flange that is in contact with the elastic base on the maximum tensile stresses and maximum deflection. The effect on the stressed-deformed state of the various cross-section forms is carried out in work for an I-beam, a rectangle, and a T-beam. Related to the fact that for many building materials the elastic moduli for tension and compression differ, it became necessary to determine the influence of material heterogeneity on the stress-strain state of the elements of building structures. In particular, the widespread use of reinforced concrete beams as elements of band foundations requires a refinement of the stress-strain state study taking into account the heterogeneity of concrete.

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.

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