scholarly journals The strength of compressed structures with CFRP materials reinforcement when exceeding the cross-section size

2018 ◽  
Vol 33 ◽  
pp. 02060 ◽  
Author(s):  
Petr Polskoy ◽  
Dmitry Mailyan ◽  
Sergey Georgiev ◽  
Viktor Muradyan
Keyword(s):  
Bearing Capacity ◽  
Cross Section ◽  
High Strength ◽  
Material Consumption ◽  
High Rise ◽  
Labour Costs ◽  
Section Size ◽  
Strength And Deformation ◽  
The Cross ◽  
Composite Reinforcement

The increase of high-rise construction volume or «High-Rise Construction» requires the use of high-strength concrete and that leads to the reduction in section size of structures and to the decrease in material consumption. First of all, it refers to the compressed elements for which, when the transverse dimensions are reduced, their flexibility and deformation increase but the load bearing capacity decreases. Growth in construction also leads to the increase of repair and restoration works or to the strengthening of structures. The most effective method of their strengthening in buildings of «High-Rise Construction» is the use of composite materials which reduces the weight of reinforcement elements and labour costs on execution of works. In this article the results of experimental research on strength and deformation of short compressed reinforced concrete structures, reinforced with external carbon fiber reinforcement, are presented. Their flexibility is λh=10, and the cross-section dimensions ratio b/h is 2, that is 1,5 times more, than recommended by standards in Russia. The following research was being done for three kinds of strained and deformed conditions with different variants of composite reinforcement. The results of the experiment proved the real efficiency of composite reinforcement of the compressed elements with sides ratio equal to 2, increasing the bearing capacity of pillars till 1,5 times. These results can be used for designing the buildings of different number of storeys.

SETTING A DIAGRAM APPROACH TO CALCULATING VIBRATED, CENTRIFUGED AND VIBROCENTRIFUGED REINFORCED CONCRETE COLUMNS WITH A VARIATROPIC STRUCTURE

2020 ◽  
pp. 22-34
Author(s):  
Л. Р. Маилян ◽  
С. А. Стельмах ◽  
Е. М. Щербань ◽  
М. П. Нажуев
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Cross Section ◽  
Concrete Columns ◽  
Reinforced Concrete Columns ◽  
The Cross ◽  
Concrete Elements ◽  
Diagram Approach

Состояние проблемы. Железобетонные элементы изготавливаются, как правило, по трем основным технологиям - вибрированием, центрифугированием и виброцентрифугированием. Однако все основные расчетные зависимости для определения их несущей способности выведены, исходя из основного постулата - постоянства и равенства характеристик бетона по сечению, что реализуется лишь в вибрированных колоннах. Результаты. В рамках диаграммного подхода предложены итерационный, приближенный и упрощенный способы расчета несущей способности железобетонных вибрированных, центрифугированных и виброцентрифугированных колонн. Выводы. Расчет по диаграммному подходу показал существенно более подходящую сходимость с опытными данными, чем расчет по методике норм, а также дал лучшие результаты при использовании дифференциальных характеристик бетона, чем при использовании интегральных и, тем более, нормативных характеристик бетона. Statement of the problem. Reinforced concrete elements are typically manufactured according to three basic technologies - vibration, centrifugation and vibrocentrifugation. However, all the basic calculated dependencies for determining their bearing capacity were derived using the main postulate, i.e., the constancy and equality of the characteristics of concrete over the cross section, which is implemented only in vibrated columns. Results. Within the framework of the diagrammatic approach, iterative, approximate and simplified methods of calculating the bearing capacity of reinforced concrete vibrated, centrifuged and vibrocentrifuged columns are proposed. Conclusions. The calculation according to the diagrammatic approach showed a significantly better convergence with the experimental data than that using the method of norms, and also performs better when using differential characteristics of concrete than when employing integral and particularly standard characteristics of concrete.

scholarly journals Are We Able to Print Components as Strong as Injection Molded?—Comparing the Properties of 3D Printed and Injection Molded Components Made from ABS Thermoplastic

2021 ◽  
Vol 11 (15) ◽  
pp. 6946
Author(s):  
Bartłomiej Podsiadły ◽  
Andrzej Skalski ◽  
Wiktor Rozpiórski ◽  
Marcin Słoma
Keyword(s):  
Tensile Strength ◽  
Injection Molding ◽  
Mechanical Strength ◽  
Cross Section ◽  
Fused Deposition Modeling ◽  
High Strength ◽  
Large Cross Section ◽  
Fused Deposition ◽  
Injection Molded ◽  
The Cross

In this paper, we are focusing on comparing results obtained for polymer elements manufactured with injection molding and additive manufacturing techniques. The analysis was performed for fused deposition modeling (FDM) and single screw injection molding with regards to the standards used in thermoplastics processing technology. We argue that the cross-section structure of the sample obtained via FDM is the key factor in the fabrication of high-strength components and that the dimensions of the samples have a strong influence on the mechanical properties. Large cross-section samples, 4 × 10 mm2, with three perimeter layers and 50% infill, have lower mechanical strength than injection molded reference samples—less than 60% of the strength. However, if we reduce the cross-section dimensions down to 2 × 4 mm2, the samples will be more durable, reaching up to 110% of the tensile strength observed for the injection molded samples. In the case of large cross-section samples, strength increases with the number of contour layers, leading to an increase of up to 97% of the tensile strength value for 11 perimeter layer samples. The mechanical strength of the printed components can also be improved by using lower values of the thickness of the deposited layers.

Springback law of high-strength 21-6-9 stainless steel tube in numerical control bending under different process parameters

2015 ◽  
Vol 231 (10) ◽  
pp. 1783-1792 ◽  
Author(s):  
Jun Fang ◽  
Shiqiang Lu ◽  
Kelu Wang ◽  
Zhengjun Yao
Keyword(s):  
Stainless Steel ◽  
Friction Coefficient ◽  
Cross Section ◽  
Process Parameters ◽  
High Strength ◽  
Steel Tube ◽  
Numerical Control ◽  
Stainless Steel Tube ◽  
Outer Diameter ◽  
The Cross

In order to achieve the precision bending deformation, the effects of process parameters on springback behaviors should be clarified preliminarily. Taking the 21-6-9 high-strength stainless steel tube of 15.88 mm × 0.84 mm (outer diameter × wall thickness) as the objective, the multi-parameter sensitivity analysis and three-dimensional finite element numerical simulation are conducted to address the effects of process parameters on the springback behaviors in 21-6-9 high-strength stainless steel tube numerical control bending. The results show that (1) springback increases with the increasing of the clearance between tube and mandrel Cm, the friction coefficient between tube and mandrel fm, the friction coefficient between tube and bending die fb, or with the decreasing of the mandrel extension length e, while the springback first increases and then remains unchanged with the increasing of the clearance between tube and bending die Cb. (2) The sensitivity of springback radius to process parameters is larger than that of springback angle. And the sensitivity of springback to process parameters from high to low are e, Cb, Cm, fb and fm. (3) The variation rules of the cross section deformation after springback with different Cm, Cb, fm, fb and e are similar to that before springback. But under same process parameters, the relative difference of the most measurement section is more than 20% and some even more than 70% before and after springback, and a platform deforming characteristics of the cross section deformation is shown after springback.

scholarly journals Optimization of Geometrical Parameters of Hollow-core Slabs by Formwork-free Shaping for Construction in Seismic Areas

2020 ◽  
Vol 8 (6) ◽  
pp. 4973-4977
Keyword(s):  
Cross Section ◽  
High Strength ◽  
Geometrical Parameters ◽  
Hollow Core ◽  
Constructive Solution ◽  
Industrial Buildings ◽  
Operational Load ◽  
Wide Range ◽  
Hollow Core Slab ◽  
The Cross

The building norms and standards of Uzbekistan on the reinforced concrete structures do not regulate the design of hollow-core slabs of formwork-free shaping, reinforced with prestressed wire reinforcement. The manufacturing technology of such slabs allows creating a wide range of products that increase the possibility of their use in various structural systems in residential, civil and industrial buildings, but in non-seismic areas only. The aim of this work is to develop a constructive solution for the cross section of a prestressed hollow-core floor slab of bench formwork-free shaping, reinforced with high-strength wire reinforcement, in order to create a wide range of products intended for construction in seismic areas. To achieve the goal, the problem of determining the optimal combination of height and configuration parameters of the cross section of such a slab is solved, meeting the normalized operational requirements and limitations of earthquake-resistant building standards. The main variable parameters are the height and the void degree of the section, characterized by the size and shape of voids. In calculating the cross-section of a hollow-core slab when substantiating the theoretical basis for the calculation, the cross section is reduced to the equivalent I-section. As a result of research, a constructive solution was developed for the slab cross section of the maximum parameter values (the span, operational load) set by the customer. The parameters of the slab cross-section are: the height 190 mm, the hollowness 38%, the height of the upper thickened flange (compared with the height of the lower flange) of the given section is 0.27h, the height of the lower flange is 0.17h, the reduced (total) thickness of all ribs “b” is 0.32 of the width of the upper flange. The voids in the section along the height of the slab are arranged asymmetrically. A patent for a utility model has been received for the proposed constructive solution of the slab cross section.

scholarly journals Experimental and Numerical Study on Ultimate Shear Load Carrying Capacity of Corroded RC Beams

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Zhanzhan Tang ◽  
Zhixiang He ◽  
Zheng Chen ◽  
Lingkun Chen ◽  
Hanyang Xue ◽  
...  
Keyword(s):  
Shear Strength ◽  
Bearing Capacity ◽  
Cross Section ◽  
Loss Rate ◽  
Numerical Study ◽  
Rc Beams ◽  
Load Carrying ◽  
Shear Bearing Capacity ◽  
The Cross ◽  
The Impact

For an RC beam, the strength of steel rebar, the bonding strength between the concrete and reinforcement, and the bite action between the aggregates will deteriorate significantly due to corrosion. In the present study, 10 RC beams were designed to study the impact of corrosion on the shear bearing capacity. The mechanism of corrosion for stirrups and longitudinal bars and their effects were analyzed. Based on the existing experimental data, the correlation between the stirrup corrosion factor and the cross section loss rate was obtained. An effective prediction formula on the shear bearing capacity of the corroded RC beams was proposed and validated by the experimental results. Moreover, a numerical analysis approach based on the FE technique was proposed for the prediction of the shear strength. The results show that corrosion of the reinforcements could reduce the shear strength of the RC beams. The corrosion of stirrups can be numerically simulated by the reduction of the cross section. The formulae in the literature are conservative and the predictions are very dispersed, while the predictions by the proposed formula agree very well with the experiment results.

scholarly journals Studying the influence of the cross section height on the distribution of the internal efforts of wooden glued beams

2019 ◽  
Vol 135 ◽  
pp. 03048
Author(s):  
Sergei Prokhorov
Keyword(s):  
Cross Section ◽  
High Strength ◽  
Large Error ◽  
Environmental Friendliness ◽  
High Rise ◽  
Reinforced Beams ◽  
Flexural Member ◽  
Strength And Stiffness ◽  
Capital Construction ◽  
Wooden Structures

Since ancient times, wooden structures have been used by man for the construction of buildings and facilities. For many centuries, the structural elements of buildings and facilities made of wood have been the main ones, and still have broad prospects for use in modern capital construction, as they have sufficient high strength and stiffness, are reliable and durable, while having a small mounting weight. In particular, a number of Western countries are already erecting high-rise buildings using a framework of laminated wood constructions. The indisputable advantage of wooden structures is environmental friendliness. However, with all the harmony of the wood structure, its tracheid’s are not standard, which is the main reason for the variability of its mechanical properties. With alteration of a cross-section of flexural member, the nature of the load distribution, as well as the nature of the fracture, changes. An additional factor that affecting the force distribution is the nature of the reinforcement and methods of the reinforcement fixing methods. The methods used to calculate the “low” reinforced beams often give a large error in the calculation of “high” beams. In the work, a rational methodology for calculating wooden glued reinforced beams with symmetrical reinforcement is determined.

Study on the Porosity in Al-Zn-Mg-Cu High Strength Alloy DC Ingot

2016 ◽  
Vol 879 ◽  
pp. 790-794 ◽  
Author(s):  
Hui Xue Jiang ◽  
Hiromi Nagaumi ◽  
Shi Jie Guo ◽  
Chun Zou
Keyword(s):  
Cooling Rate ◽  
Cross Section ◽  
High Strength ◽  
Direct Chill ◽  
Thickness Direction ◽  
X Ray ◽  
Density Method ◽  
Width Direction ◽  
Strength Alloy ◽  
The Cross

An Al-Zn-Mg-Cu high strength alloy ingot produced by Direct-Chill casting was used in this study. The distribution of porosity in the cross section of the DC ingot was investigated by the precision density method (Archimeds’ principle), also X-ray microtomography technique was used to quantitatively analyze porosities in typical positions. The pattern in the cross section as well as in the thickness and width direction was obtained. The results show that: in the cross section of the ingot, porosity was increasing gradually from the surface to the center of the ingot; porosity shows an overall escalating trend from the surface to the center of the ingot both in thickness direction and in width direction; porosity was closely related to the cooling rate in the ingot; oxide inclusions have an effect on the formation of porosity to some extent.

scholarly journals Non-linear Analysis of Slender High Strength Concrete Column

2019 ◽  
Vol 5 (7) ◽  
pp. 1440-1451
Author(s):  
Ernesto Fenollosa ◽  
Iván Cabrera ◽  
Verónica Llopis ◽  
Adolfo Alonso
Keyword(s):  
Bearing Capacity ◽  
Cross Section ◽  
Axial Force ◽  
High Strength Concrete ◽  
Bending Moment ◽  
High Strength ◽  
Concrete Columns ◽  
Strength Concrete ◽  
The Moment ◽  
High Strength Concrete Columns

This article shows the influence of axial force eccentricity on high strength concrete columns design. The behavior of columns made of normal, middle and high strength concrete with slenderness values between 20 and 60 under an eccentric axial force has been studied. Structural analysis has been developed by means of software which considers both geometrical and mechanical non-linearity. The sequence of points defined by increasing values of axial force and bending moment produced by eccentricity has been represented on the cross-section interaction diagram until failure for each tested column. Then, diagrams depicting the relationship between failure axial force and column's slenderness have been drawn. The loss of bearing capacity of the member for normal and middle strength columns when compared with the bearing capacity of their cross-section is more noticeable as axial force eccentricity assumes higher values. However, this situation reverses for high strength columns with high slenderness values. On the basis of results obtained, the accuracy level for the moment magnifier method was checked. Despite the good concordance in most of the cases, it was verified that the moment magnifier method leads to excessively tight results for high strength concrete columns with high slenderness values. In these specific cases, a coefficient which amends the column rigidity is proposed so as to obtain safer values.

scholarly journals CRITERION OF MINIMUMMATERIAL CONSUMPTIONOF FLANGE OF I-SHAPED BAR WITH A VARIATION IN ITS THICKNESS ANDOUTLINE OF THE WIDTH, WITH RESTRICTION TO THE VALUE OF THE CRITICALFORCE OR RESTRICTIONTO THE VALUE OF THEFIRSTNATURAL FREQUENCY INTWO PRINCIPAL PLANESO

2018 ◽  
Vol 14 (2) ◽  
pp. 96-108
Author(s):  
Leonid S. Lyakhovich ◽  
Pavel A. Akimov ◽  
Boris A. Tukhfatullin
Keyword(s):  
Natural Frequency ◽  
Cross Section ◽  
Critical Force ◽  
Principal Plane ◽  
Material Consumption ◽  
The Cross ◽  
The Stability

We have already presented original criterion of minimum material consumption within the design of the outline of the width of the I-shaped bar and the stability constraints or restriction to the value of the first natu­ral frequency in one principal plane of inertia of the cross-section. This paper is devoted in its turn to a criterion for the minimum material capacity of the I-shaped bar with a variation in its thickness and outline of the width, with restrictions to the value of the critical force or restriction to the value of the first natural frequency in two principal planes of inertia of the section

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