Design of Slender Reinforced Concrete Columns of Annular Cross-Section According to the Nominal Curvature Method and the Exact Method

2017 ◽  
Author(s):  
Krzysztof Klempka ◽  
Marek Jedrzejczak
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Concrete Columns ◽  
Exact Method ◽  
Reinforced Concrete Columns ◽  
Annular Cross Section

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 Behavior of reinforced concrete columns strenghtened by partial jacketing

2016 ◽  
Vol 9 (1) ◽  
pp. 1-21 ◽  
Author(s):  
D. B. FERREIRA ◽  
R. B. GOMES ◽  
A. L. CARVALHO ◽  
G. N. GUIMARÃES
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Concrete Columns ◽  
The Other ◽  
Self Compacting Concrete ◽  
Reinforced Concrete Columns ◽  
Compressive Stresses ◽  
Concrete Layer ◽  
Ultimate Resistance

This article presents the study of reinforced concrete columns strengthened using a partial jacket consisting of a 35mm self-compacting concrete layer added to its most compressed face and tested in combined compression and uniaxial bending until rupture. Wedge bolt connectors were used to increase bond at the interface between the two concrete layers of different ages. Seven 2000 mm long columns were tested. Two columns were cast monolithically and named PO (original column) e PR (reference column). The other five columns were strengthened using a new 35 mm thick self-compacting concrete layer attached to the column face subjected to highest compressive stresses. Column PO had a 120mm by 250 mm rectangular cross section and other columns had a 155 mm by 250mm cross section after the strengthening procedure. Results show that the ultimate resistance of the strengthened columns was more than three times the ultimate resistance of the original column PO, indicating the effectiveness of the strengthening procedure. Detachment of the new concrete layer with concrete crushing and steel yielding occurred in the strengthened columns.

scholarly journals Analysis of the behavior of reinforced concrete columns strengthened with sleeve wedge bolts and a self compacting concrete layer

2015 ◽  
Vol 8 (2) ◽  
pp. 88-99
Author(s):  
M. G. Marques ◽  
A. P. A. R. Liserre ◽  
R. B. Gomes ◽  
G. N. Guimarães
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Concrete Columns ◽  
Concrete Surface ◽  
Self Compacting Concrete ◽  
Reinforced Concrete Columns ◽  
Concrete Layer ◽  
Strength Capacity ◽  
Strengthening Technique

Strengthening of reinforced concrete columns by jacketing is one of the most common structural rehabilitation techniques in Brazil. For adequate performance, it is necessary, among others, to avoid detachment of the new concrete layer (strengthening material) from the old concrete substrate when the strengthened member is again in service conditions. This paper describes the test results of eight reinforced concrete rectangular columns subjected to combined compression and one-axis bending to evaluate the efficiency of using sleeve wedge bolts across the new concrete/old concrete interface to avoid detachment. The strengthening technique, in this case, consists of adding a layer of self-compacting concrete to one face of the column. Two columns tested were monolithic and named PO (original column) e PR (reference column). The other six columns were strengthened using a new 35 mm thick self-compacting concrete layer attached to the column face subjected to highest compressive stresses. Column PO had a 120mm by 250 mm rectangular cross section and its results gave information about column behavior without the use of strengthening. Column PR had a 155mm by 250 mm rectangular cross section and its cross section dimensions matched the strengthened columns but it was cast monolithically. To improve bond conditions between the existing concrete and the new concrete, the concrete surface was roughened and the outermost aggregate was exposed using hydro jetting. Holes along the concrete surface were made to insert the wedge bolts responsible for increasing the bond between the two concrete surfaces. The difference among the six strengthened columns was the position and amount of bolts used. Results indicate that the position and amount of the bolts alters significantly the strength capacity of the columns, since premature rupture by concrete detachment was delayed.

scholarly journals Investigation of Parameters Affecting the Equivalent Yield Curvature of Reinforced Concrete Columns

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1594
Author(s):  
Umut Hasgul
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Axial Load ◽  
Concrete Columns ◽  
Load Level ◽  
Combined Effects ◽  
Reinforced Concrete Columns ◽  
Independent Effects ◽  
Equivalent Yield ◽  
Section Dimension

In this study, the response quantities affecting the equivalent yield curvature, which is important in the deformation-based seismic design and assessment of structural systems, are investigated for reinforced concrete columns with a square cross-section. In this context, the equivalent yield curvatures were determined by conducting moment–curvature analyses on various column models, in which the axial load level, cross-section dimension, longitudinal reinforcement ratio, and concrete compression strength were changed parametrically, and the independent and/or combined effects of the relevant parameters were discussed. Depending on the axial load levels of P/Agfc′ < 0.3, P/Agfc′ = 0.3, and P/Agfc′ > 0.3 for the considered columns, the yielding of reinforcement, yielding of reinforcement and/or concrete crushing, and concrete crushing governed the yield conditions, respectively. It can be noted that the cross-section dimension and axial load level became the primary parameters. Even though the independent effects with regard to particular parameters remained at minimal levels, the combined effects of them with the axial load became important in terms of the equivalent yield curvature.

scholarly journals Transverse Reinforcement in Reinforced Concrete Columns

2013 ◽  
Vol 8 (2) ◽  
pp. 41-50
Author(s):  
Štefan Gramblička ◽  
Peter Veróny
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Concrete Columns ◽  
Transverse Reinforcement ◽  
Transverse Deformation ◽  
Reinforced Concrete Columns

Abstract In the article we are dealing with the influence of transverse reinforcement to the resistance of a cross-section of the reinforced concrete columns and also with the effective detailing of the column reinforcement. We are verifying the correctness of design guides for detailing of transverse reinforcement. We are also taking into account the diameter of stirrups and its influence over transverse deformation of column.

STRESS-STRAIN STATE OF ECCENTRICALLY COMPRESSED REINFORCED CONCRETE COLUMNS OF CIRCULAR CROSS-SECTION

2018 ◽  
Vol 8 (1) ◽  
pp. 4-9
Author(s):  
Sergey S. MORDOVSKY ◽  
Rustam I. DAVLIKAMOV
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Nonlinear Deformation ◽  
Strain State ◽  
Circular Cross Section ◽  
Concrete Columns ◽  
Deformation Model ◽  
Stress Strain ◽  
Reinforced Concrete Columns ◽  
Nonlinear Deformation Model

Theoretical studies of reinforced concrete eccentrically compressed columns of circular cross-section on strength indexes are analyzed. These studies rely on the use of a nonlinear deformation model that approximates the work of concrete to real experimental conditions. A comparative analysis of the results of calculating the strength of reinforced concrete columns of circular cross-section is carried out according to the methodology proposed in the current set of rules, is the author’s program for determining the stress-strain state of a reinforced concrete column of circular cross-section implemented in the MathCad software environment. The results of a numerical experiment are compared in the form of a fi nite-element model in the Lira-CAD program complex using a nonlinear deformation model. Calculations and schemes are given taking into account the possibility of conducting an experimental study.

scholarly journals Numerical analysis of reinforced concrete shear walls with rectangular cross section

2020 ◽  
Vol 13 (6) ◽  
Author(s):  
Maurício Castelo Branco de Noronha Campos ◽  
Paulo Marcelo Vieira Ribeiro ◽  
Romilde Almeida de Oliveira
Keyword(s):  
Reinforced Concrete ◽  
Numerical Analysis ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Concrete Columns ◽  
Second Order ◽  
Order Effects ◽  
Cross Sectional ◽  
Reinforced Concrete Columns ◽  
Mesh Model

abstract: This study addresses a numerical analysis of reinforced concrete columns in which the lengths are significantly larger than their widths with a rectangular cross section. Numerical simulations of 1,440 cases were performed, each case simulated with the single bar model, isolated bar model and mesh model, in addition, 3D model simulations were carried out. For the validation of 3D models and bar models, comparisons were made between the numerical simulation e experimental results of 24 reinforced concrete columns. Second order effects were analyzed on the vertical moment at the edge of the columns in which the lengths are significantly larger than the widths (localized second-order effects) and also the values of the horizontal moments along the cross sectional length in the mesh model. Influences of the main variables were observed influencing the behavior of the columns in which the lengths are significantly larger than their widths: the ratio between the cross sectional dimensions, the slenderness and the stresses (normal stress and bending moment around the axis of greatest inertia).

scholarly journals Behaviour of Rectangular Reinforced Concrete Columns with Disproportionate Cross-Section Dimensions Subjected to Compression and Biaxial Bending - Case Study

2020 ◽  
Vol 9 (1) ◽  
pp. 94-107
Author(s):  
Savu Adrian-Alexandru
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Seismic Design ◽  
Concrete Columns ◽  
Biaxial Bending ◽  
Seismic Behaviour ◽  
Reinforced Concrete Columns ◽  
Seismic Design Code ◽  
Interaction Curves

Abstract The purpose of the current paper is to raise awareness on the behaviour of rectangular reinforced concrete columns with disproportionate cross-section dimensions subjected to compression and biaxial bending, considering the fact that in the current structural design process, the design of columns is usually done with respect to each of the two principal directions without considering their combined effect. The paper is based on a case study regarding a building that is currently in the design phase, in which to obtain a correct seismic behaviour, rectangular columns with disproportionate cross-section dimensions were used. The design of both the building and the columns follows the Romanian seismic design codes (“P100-1/2013 - Seismic design code - Part 1 - Design provisions for buildings” and “SR-EN 1998/2004 - Design of structures for earthquake resistance”). Results were compared and conclusions were drawn based on the interaction curves and interaction surfaces computed with expressions from specialized literature and sectional analysis software.

A solution to the thermal problem of fire resistance of spun reinforced concrete columns

2021 ◽  
Vol 30 (2) ◽  
pp. 49-70
Author(s):  
I. I. Palevoda ◽  
D. S. Nekhan
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Cross Sections ◽  
Fire Resistance ◽  
Concrete Structures ◽  
Concrete Columns ◽  
Full Scale ◽  
Reinforced Concrete Structures ◽  
Thermal Problem ◽  
Reinforced Concrete Columns

Introduction. Spun reinforced concrete columns are widely used in the present-day international construction practice. Known formulas, used to calculate temperatures of cross sections of reinforced concrete structures, needed to assess their fire resistance limit, are successfully applied to homogeneous structures that have solid sections. However, they are inapplicable to spun reinforced concrete columns due to their structural features. The purpose of this work is to develop a method for solving a thermal problem of spun reinforced concrete columns and adapt existing calculation formulas.Materials and methods. This work addresses the heating of spun reinforced concrete structures in case of fire. Ansys Workbench was employed to perform the computer simulation needed to study the influence of the characteristics of spun reinforced concrete columns on their heating. Results and discussion. In the course of the theoretical studies, the effect, produced by column cavities, the heterogeneity of spun concrete and thin walls of these structures on the heating of their cross sections was assessed with regard for the results of full-scale fire tests of spun reinforced concrete columns. Correction coefficients were obtained in order to take account of these factors. A regression equation was derived as a result of the simulation performed in the context of a full-scale factorial experiment involving coefficient khol, which takes into account the rising temperature of hollow reinforced concrete structures in comparison with solid ones. Khet heating acceleration coefficient is applicable to spun reinforced concrete structures due to the heterogeneity of concrete in the cross section. This coefficient represents a function of the wall thickness. Coefficient kth, which allows for the heating acceleration in the course of crack opening in thin-walled structures, varies in the range of 1.00…1.40. The concrete cracking temperature is 550 °C.Conclusion. A new method allows to solve the thermal problem of fire resistance of spun reinforced concrete columns. The engineering formula used to calculate the temperature in a cross-section was adapted. The results of computer-aided simulation and calculation of temperature values, performed using the adapted formula, show acceptable convergence with the experimental data.

scholarly journals Experimental analysis of eccentrically loaded reinforced concrete columns with an added jacket of self-compacting concrete

2019 ◽  
Vol 12 (2) ◽  
pp. 329-336
Author(s):  
J. P. VIRGENS ◽  
R. B. GOMES ◽  
L. M. TRAUTWEIN ◽  
G. N. GUIMARÃES ◽  
A. P. R. VAZ
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Ultimate Load ◽  
Load Capacity ◽  
Concrete Columns ◽  
Reinforce Concrete ◽  
Self Compacting Concrete ◽  
Ultimate Load Capacity ◽  
Reinforced Concrete Columns ◽  
Concrete Layer

Abstract This paper presents the experimental study of eccentrically loaded reinforced concrete columns with an added 35 mm self-compacting concrete jacket attached to the column’s most compressed face using wedge bolts. Nine columns with a 2000 mm height were tested under compression and one-way bending until failure. Columns were denominated as original column (PO) with a cross section of 120 mm x 250 mm; reference column (PR) with a cross section of 155 mm x 250 mm, and seven columns with an initial cross section of 120 mm x 250 mm and later reinforced by the addition of 35 mm self-compacting concrete layer and various configurations of wedge bolts. Except for the original column PO, the columns were submitted to a 42.5 mm load eccentricity due to the added concrete layer at the compressed face. Although failure of the wedge bolts did not occur, it was not possible to prevent detachment of the added layer. The results indicate that it is possible to structurally rehabilitate reinforce concrete columns with the use of the strengthening methodology used in this research, resulting in average ultimate load capacity gains of 271% compared to original column’s ultimate load.

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