Studying the Behavior of Reinforced Concrete Columns Confined by Steel Structure Under Eccentrically Loading

2020 ◽  
Vol 25 (1) ◽  
pp. 65-86
Author(s):  
احسان الطرشة ◽  
علي الجراش ◽  
فلاح مبارك

Abstract This research paper presents an analytical study of a number of Reinforced  Concrete Columns models which have rectangular cross section and confined/unconfined by steel Structure of vertical angles and horizontal plates. Columns are subjected to centric and eccentric compression load. The objective is to know how far the bracing is effective in increasing the strength of these columns. This type of strengthening is considered better than the concrete Structure, Carbon Fiber Reinforced Polymer (CFRP) and other types because it has many features, easy and fast to be constructed. The study demonstrated that the bracing by steel Structure led to increase the strength in large ratios and had been clear that once the thickness of steel Structure is increased, the strength increases. And once the eccentricity is increased, the strength decreases and also the failure load. Keywords: reinforced concrete columns, bracing, steel structure, centriccompression, eccentric compression, steel structure thickness, strengtheningeffectiveness, failure load.

2012 ◽  
Vol 446-449 ◽  
pp. 311-317
Author(s):  
Ji Zhong Wang ◽  
Yong Feng Wang ◽  
Su Yan Wang

This paper compares three standards of FRP strengthened concrete columns published by ACI committee, Concrete Society and China respectively. A test is designed according to the comparison. A total of five columns were cast and tested. The analysis of the load bearing capacity and ductility of the test result indicates that wrapping hoop GFRP can enhance load bearing capacity slightly and the ductility greatly, wrapping axial GFRP can enhance load bearing capacity greatly but the failure of column is brittle, wrapping axial GFRP over-wrapped with hoop GFRP can both enhance load bearing capacity and the ductility.


2010 ◽  
Vol 3 (3) ◽  
pp. 271-283 ◽  
Author(s):  
M. Y. M. Omar ◽  
R. B. Gomes ◽  
A. P. A. Reis

This paper presents the results of reinforced concrete columns strengthened by addition of a self-compacting concrete overlay at the compressed and at the tensioned face of the member, with and without addition of longitudinal steel bars. Eight columns were submit- ted to loading with an initial eccentricity of 60 mm . These columns had 120 mm x 250 mm of rectangular cross section, 2000 mm in length and four longitudinal reinforcement steel bars with 10 mm in diameter. Reference columns P1 and P2 were tested to failure without any type of rehabilitation. Columns P3 to P8 were loaded to a predefined load (close to the initial yield point of tension reinforce- ment), then unloaded and strengthened for a subsequent test until failure. Results showed that the method of rehabilitation used was effective, increasing the loading capacity of the strengthened pieces by 2 to 5 times the ultimate load of the reference column.


2016 ◽  
Vol 9 (1) ◽  
pp. 1-21 ◽  
Author(s):  
D. B. FERREIRA ◽  
R. B. GOMES ◽  
A. L. CARVALHO ◽  
G. N. GUIMARÃES

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.


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