scholarly journals Experimental analysis of reinforcing columns of reinforced concrete, with anchor steel bolts

2016 ◽  
Vol 9 (5) ◽  
pp. 796-823
Author(s):  
A. C. MESQUITA ◽  
A. S. ROCHA ◽  
R. G. DELALIBERA ◽  
W. A. DA SILVA
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Cross Section ◽  
Experimental Analysis ◽  
Load Capacity ◽  
Concrete Columns ◽  
Self Compacting Concrete ◽  
Reinforced Concrete Columns ◽  
Structural Rehabilitation ◽  
Steel Bolts

Abstract This article presents a columns reinforcement experimental study, with the use of anchor steel bolts and fill with self-compacting concrete. Were tested five columns of reinforced concrete subjected to flexion-compression: two columns were used as reference, and a cross-section equal to 120 x 250 mm; with a monolithic section equal to 155 x 250 mm cross section of the same reinforced columns and three which were initially molded with a 120 x 250 mm section and subsequently received a layer of 35 mm thick self-compacting concrete in the compressed side. Despite the studs do not present break, there was peeling of the reinforcement layer. The results indicate the possibility of using this method in reinforcing structural rehabilitation of reinforced concrete columns, with increase in load capacity on average equal to 403% in relation to the column reference.

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.

scholarly journals Experimental analysis of reinforced concrete columns strengthened with self-compacting concrete and connectors

2012 ◽  
Vol 5 (3) ◽  
pp. 305-315
Author(s):  
P. P. Nascimento ◽  
R. B. Gomes ◽  
L. L. J. Borges ◽  
D. L. David
Keyword(s):  
Reinforced Concrete ◽  
Failure Mode ◽  
Experimental Analysis ◽  
Thick Layer ◽  
Concrete Columns ◽  
The Other ◽  
Experimental Phase ◽  
Self Compacting Concrete ◽  
Reinforced Concrete Columns ◽  
Steel Bars

There are many problems involving cases of destruction of buildings and other structures. The columns can deteriorate for several reasons such as the evolution and changing habits of the loads. The experimental phase of this work was based on a test involving nine reinforced concrete columns under combined bending and axial compression, at an initial eccentricity of 60 mm. Two columns were used as reference, one having the original dimensions of the column and the other, monolithic, had been cast along the thickness of the strengthened piece. The remaining columns received a 35 mm thick layer of self-compacting concrete on their compressed face. For the preparation of the interface between the two materials, this surface was scarified and furrowed and connectors were inserted onto the columns' shear reinforcement in various positions and amounts.As connectors, 5 mm diameter steel bars were used (the same as for stirrups), bent in the shape of a "C" with 25 mm coatings. >As a conclusion, not only the quantity, but mainly, the location of the connectors used in the link between substrate and reinforcement is crucial to increase strength and to change failure mode.

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.

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.

A combined experimental and numerical analysis on the seismic behavior of short reinforced concrete columns with different structural sizes and axial compression ratios

2017 ◽  
Vol 27 (9) ◽  
pp. 1416-1447 ◽  
Author(s):  
Liu Jin ◽  
Shuai Zhang ◽  
Dong Li ◽  
Haibin Xu ◽  
Xiuli Du ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Energy Dissipation ◽  
Axial Compression ◽  
Seismic Behavior ◽  
Load Capacity ◽  
Concrete Columns ◽  
Simulation Method ◽  
Reinforced Concrete Columns ◽  
Mesoscopic Simulation ◽  
Energy Dissipation Capacity

The results of an experimental program on eight short reinforced concrete columns having different structural sizes and axial compression ratios subjected to monotonic/cyclic lateral loading were reported. A 3D mesoscopic simulation method for the analysis of mechanical properties of reinforced concrete members was established, and then it was utilized as an important supplement and extension of the traditional experimental method. Lots of numerical trials, based on the restricted experimental results and the proposed 3D mesoscopic simulation method, were carried out to sufficiently evaluate the seismic performances of short reinforced concrete columns with different structural sizes and axial compression ratios. The test results indicate that (1) the failure pattern of reinforced concrete columns can be significantly affected by the shear-span ratio; (2) increasing the axial compression ratio could improve the load capacity of the reinforced concrete column, but the deformation capacity would be restricted and the failure mode would be more brittle, consequently the energy dissipation capacity could be deteriorated; and (3) the load capacity, the displacement ductility, and the energy dissipation capacity of the short reinforced concrete columns all exhibit clear size effect, namely, the size effect could significantly affect the seismic behavior of reinforced concrete columns.

scholarly journals Experimental study of the strengthening effect of reinforced concrete columns jacketed under service load level

2018 ◽  
Vol 183 ◽  
pp. 02008 ◽  
Author(s):  
Pavlo Krainskyi ◽  
Yaroslav Blikharskyy ◽  
Roman Khmil ◽  
Zinoviy Blikharskyy
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Concrete Columns ◽  
Load Level ◽  
Strengthening Effect ◽  
Engineering Structures ◽  
Reinforced Concrete Columns ◽  
Technical Modification ◽  
Service Load

The need of structural retrofitting and strengthening of different buildings, engineering structures or their elements is always present. Among the main reasons are demages and material deterioration due to aging, improper maintenance or physical damages; planed repairs; reconstruction or extension of the building; technical modification or complete change of operations inside the building or the structure, etc. In some cases operation of the building during retrofitting or strengthening of its structures has to be partially or fully stopped. In other cases the strengthening process takes place while the building is still operational which means that structures are strengthened under service loads. The main goal of this research is to determine the strengthening effect of reinforced concrete jacketing applied to columns under service load level. For that the experimental study of six reinforced concrete columns were carried out: four reference columns, both strengthened by jacketing and unstrengthened and two strengthened under service load. The main results of the research are presented.

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