scholarly journals Influence of Geometrical Parameters of the Cross Section, Strength and Deformability of the Materials Used on Stress-strain State of Three-layered Reinforced Concrete

Author(s):  
Vu Dinh Tho ◽  
Elena Anatonievna Korol
Buildings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 248
Author(s):  
Alexey Beskopylny ◽  
Elena Kadomtseva ◽  
Besarion Meskhi ◽  
Grigory Strelnikov ◽  
Oleg Polushkin

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.


2016 ◽  
Vol 5 (2) ◽  
pp. 122
Author(s):  
Ruslan Rachkevych ◽  
Iryna Rachkevych

<p class="1Body">This study analyses the stress-strain state of a drill string at the section of the borehole with a cavern/chute. The study was conducted to obtain analytical dependencies to determine normal bending stress in the cross section of the drill string and its downforces to the walls of the well. This will allow to compare these values with the critical ones, and draw conclusions about the possibility and duration of the drill string operation under these conditions.</p><p class="1Body">The study is based on modelling the drill string as a beam, which indicates longitudinal and transverse load and deforms in-plane.</p><p class="1Body">The formulas obtained to determine stresses and pressing forces apply to the following cases of the relative position of the drill string in a straight borehole and a curved borehole with a cavern/chute: a – the drill string touches only the bottom of the borehole; b – the drill string touches only the bottom of the borehole and the bottom of the cavern/chute; c –  the drill string touches the top and the bottom of the borehole; d – the drill string touches the top and the bottom of the borehole and the cavern/chute.</p><p class="1Body">The calculations based on the dependencies obtained lead to the following conclusions: a – the cavern/chute in the inclined straight borehole causes bending stress value in the cross section of drill pipes proportional to the fatigue margin of the material; b – the cavern/chute in the curved borehole may increase normal bending stress in the cross section of the borehole up to five times.</p>


2018 ◽  
Vol 196 ◽  
pp. 02003 ◽  
Author(s):  
Alexey Beskopylny ◽  
Elena Kadomtseva ◽  
Grigory Strelnikov

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.


2014 ◽  
Vol 13 (3) ◽  
pp. 065-070
Author(s):  
Zinoviy Blikharskyy ◽  
Dmytro Dubizhanskyy ◽  
Roman Khmil

Bearing capacity of normal cross section of bending concrete elements reinforced with reinforced concrete ring under load was investigated. Experimental researches of 4 sets of beams with the total number of 16 units were carried out. The results of changes of stress-strain state settings depending on the load level, additional reinforcement, influence of limit level load were analyzed. The three characteristic stages of stress-strain state of reinforced concrete beams strengthened with reinforced concrete ring were defined. Results of experimental investigations of bearing capacity of normal cross section of strengthened beams with reinforced concrete ring under load were presented. Enhancing effect was calculated. According to the results of researches of strengthened beams plots of strain of working armature depending on current bending moment were constructed.


2016 ◽  
Vol 5 (2) ◽  
pp. 128
Author(s):  
Ruslan Rachkevych ◽  
Iryna Rachkevych

<p class="1Body">This study analyses the stress-strain state of a drill string at the section of the borehole with a cavern/chute. The study was conducted to obtain analytical dependencies to determine normal bending stress in the cross section of the drill string and its downforces to the walls of the well. This will allow to compare these values with the critical ones, and draw conclusions about the possibility and duration of the drill string operation under these conditions.</p><p class="1Body">The study is based on modelling the drill string as a beam, which indicates longitudinal and transverse load and deforms in-plane.</p><p class="1Body">The formulas obtained to determine stresses and pressing forces apply to the following cases of the relative position of the drill string in a straight borehole and a curved borehole with a cavern/chute: a – the drill string touches only the bottom of the borehole; b – the drill string touches only the bottom of the borehole and the bottom of the cavern/chute; c –  the drill string touches the top and the bottom of the borehole; d – the drill string touches the top and the bottom of the borehole and the cavern/chute.</p><p class="1Body">The calculations based on the dependencies obtained lead to the following conclusions: a – the cavern/chute in the inclined straight borehole causes bending stress value in the cross section of drill pipes proportional to the fatigue margin of the material; b – the cavern/chute in the curved borehole may increase normal bending stress in the cross section of the borehole up to five times.</p>


2018 ◽  
Vol 196 ◽  
pp. 02048
Author(s):  
Valery Filatov ◽  
Zulfat Galyautdinov ◽  
Alexander Suvorov

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.


2020 ◽  
Vol 60 (4) ◽  
pp. 324-337
Author(s):  
Oksana Lytvyniak

This article presents a theoretical study of a stress-strain state of layered reinforced concrete - foam concrete floor slabs (hereinafter called as the LRFCS), with the use of a deformation analysis. Compressive and tensile diagrams of the foam concrete, a tensile diagram of the reinforced concrete and compressive and tensile diagrams of the reinforcement rod are used for the estimation of the stress-strain state of the calculated cross-section of the LRFCS. It should be noted that this article presents the deformation method of loading by the scheme of pure bending for the LRFCS. This deformation method of loading is determined by six shapes of the stress-strain state. These shapes of the stress-strain state are represented by the corresponding distribution diagrams of the relative deformations and the distribution diagrams of internal stresses in the calculated cross-section of the floor slab. Also, this article presents the corresponding equilibrium equations of internal efforts and moments, which act in the calculated cross-section of the floor slab for all shapes of its stress-strain state. Consequently, the mentioned recommendations and mathematical dependencies allow to evaluate the stress-strain state of the LRFCS from its initial loading to its destruction.


Author(s):  
D. G. Palamar ◽  
S. A. Vorobey ◽  
V. G. Razdobreev ◽  
T. V. Balahanova

The aim of the work is to study the non-uniformity of mechanical properties in the cross section of continuously cast billets of various manufacturers in Ukraine. Mechanical properties were determined by the method of measuring Brinell hardness. Mathematical relationships were developed to describe them and determine the need to take this factor into account when calculating the stress-strain state of blanks. It is established that the hardness of the surface layer of blanks, as a rule, is higher than the central zone by 0.5-7.6%. This is due to the smaller and dense dendritic structure of the surface layers. The biggest difference is observed in workpieces with a thickness of 410 mm made of steel grade 20. In workpieces made of steel grade 45, the difference in hardness of the surface layer and the central zone is 0.5-4.7% and practically does not depend on the thickness of the workpiece in the investigated interval (135-350 mm). It is shown that in the study of the stress-strain state of the metal when rolling continuously cast billets of low-carbon steels, it is advisable to take into account the uneven distribution of mechanical properties over the cross section. For medium carbon steel blanks, this factor is optional. On the basis of literature data and the results of experimental studies performed, dependencies describing the change in strength and plastic properties in the cross section of continuously cast billets of low carbon steels are proposed. These dependencies should be used in the calculation of the stress-strain state of the metal. For medium-carbon steel blanks, this factor is optional.


ScienceRise ◽  
2021 ◽  
pp. 17-23
Author(s):  
Denys Mykhailovskyi ◽  
Tetіana Sklіarova

The object of research. Long-span glulam arches are widely used as coatings for public and sports buildings. The studies carried out concern double-hinged segmental arches with spans of 60 m and more. Description of the problem. The study of the peculiarities of the work of arches as a system "soil base - foundation - above-ground structure" is associated with the significant influence of uneven deformations of supports on the stress-strain state of the above-ground structure. A change in the stress-strain state in the structure itself, associated with uneven deformations of the foundations, can lead to a significant decrease up to the complete exhaustion of the bearing capacity Main scientific results. This article provides an analysis of the change in the stress-strain state of glulam arches when calculating the system "soil base-foundation-above-ground structure". It is noted that non-uniform deformations of supports have the greatest influence on the stress in the support zones of the structure. The range of critical non-uniform subsidence has been determined, which should be limited when calculating and designing the foundations of large-span arches. It has been confirmed that double-hinged glulam arches work well in conditions of uneven subsidence due to the peculiarities of the design scheme. The results of the studies carried out and the recommendations provided will significantly improve the reliability of large-span structures and require mandatory inclusion in the current practice of calculation and design. In addition, additional requirements for the distance between mine workings for large-span structures should be introduced when performing engineering and geological surveys. This distance should be reduced for a clearer account of the deformability of the foundations for columnar foundations, and the number of workings should be increased. The area of practical use of the research results. The cross-section of the glulam arches is selected taking into account additional deformations of the supports, making it possible to avoid unpredictable damage to the structure during operation. Innovative technological product. Glulam arches, the cross-section of which is determined taking into account additional deformations from uneven subsidence of the supports Scope of application. Glulam arches calculated in this way can be used as covering for public and sports buildings for various purposes.


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