Ultimate Displacement of Reinforced Concrete Columns with Light Transverse Reinforcement

2012 ◽  
Vol 17 (2) ◽  
pp. 282-300 ◽  
Author(s):  
Cao Thanh Ngoc Tran ◽  
Bing Li
Author(s):  
Sinan Cansız

Reinforced concrete columns are the most important structural elements that determine the ductility of the structures. The main parameters affecting the behavior of reinforced concrete columns are axial load level, shear span, percent of longitudinal reinforcement and percent of transverse reinforcement. The aim of this study is to examine residual damage behavior of RC columns under cyclic loading similar to the earthquake loads combined depend on variable axial load level, spanning to depth ratio, longitudinal reinforcement ratio and transverse reinforcement ratio. When the results of experiments are examined, it can be seen that the residual drift ratio of reinforced concrete columns can be used to characterize the damage occurred in the structure after earthquake or loading. In addition, the performance level of the reinforced concrete columns according to the residual drift ratio is defined in FEMA356. As a result of this study, the analytical equation that calculates the residual drift ratio of the reinforced concrete columns at the ultimate displacement limit is proposed.


2013 ◽  
Vol 8 (2) ◽  
pp. 41-50
Author(s):  
Štefan Gramblička ◽  
Peter Veróny

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.


Author(s):  
F. A. Zahn ◽  
R. Park ◽  
M. J. N. Priestley

The results of recent experimental and analytical studies of the stress-strain behaviour of concrete confined by New Zealand manufactured Grade 275 or Grade 380 reinforcing steel are presented. First, the behaviour of three pairs of concentrically loaded reinforced concrete columns containing spirals from either Grade
275 or Grade 380 steel are compared, including the stage at which spiral fracture occurred. Second, the results of tests on four reinforced concrete columns containing Grade 380 spiral or rectangular hoop reinforcement and subjected to combined axial
load and cyclic lateral loading are reported. An analytical
study which was conducted to determine the available curvature ductility factor at the stage of fracture of the transverse reinforcement is described. The results are used to give a guideline for the safe use of Grade 380 steel as transverse confining reinforcement.


2014 ◽  
Vol 17 (10) ◽  
pp. 1373-1385 ◽  
Author(s):  
Cao Thanh Ngoc Tran ◽  
Bing Li

This paper introduces an equation developed based on the strut-and-tie analogy to predict the shear strength of reinforced concrete columns with low transverse reinforcement ratios. The validity and applicability of the proposed equation are evaluated by comparison with available experimental data. The proposed equation includes the contributions from concrete and transverse reinforcement through the truss action, and axial load through the strut action. A reinforced concrete column with a low transverse reinforcement ratio, commonly found in existing structures in Singapore and other parts of the world was tested to validate the assumptions made during the development of the proposed equation. The column specimen was tested to failure under the combination of a constant axial load of 0.30 f' c A g and quasi-static cyclic loadings to simulate earthquake actions. The analytical results revealed that the proposed equation is capable of predicting the shear strength of reinforced concrete columns with low transverse reinforcement ratios subjected to reversed cyclic loadings to a satisfactory level of accuracy


Author(s):  
Hazem Elbakry ◽  
Tarek Ebeido ◽  
El-Tony M. El-Tony ◽  
Momen Ali

Reinforced concrete columns consume large quantities of ties, especially inner cross-ties in columns with large dimensions. In some cases, nesting of the pillars occurs as a result of the presence of cross-ties. The main objective of this paper is to develop new methods for transverse reinforcement in RC columns and investigate their effect on the behavior of the columns. The proposed V-ties as transverse reinforcement replacing the ordinary and cross-ties details are economically feasible. They facilitate shorter construction periods and decrease materials and labor costs. For this purpose, experimental and numerical studies are carried out. In the experimental program, nine reinforced concrete columns with identical concrete dimensions and longitudinal reinforcing bars were prepared and tested under concentric axial load with different tie configurations. The main parameters were the tie configurations and the length (lv) of V-tie legs. As part of the numerical study, the finite element model using the ABAQUS software program obtained good agreement with the experimental results of specimens. A numerical parametric study was carried out to study the influence of concrete compressive strength and longitudinal reinforcement ratio on the behavior of RC columns with the considered tie configurations. Based on the experimental and numerical results, it was found that using V-tie techniques instead of traditional ties could increase the axial load capacity of columns, restrain early local buckling of the longitudinal reinforcing bars and improve the concrete core confinement of reinforced concrete columns.


2018 ◽  
Vol 22 (2) ◽  
pp. 459-472
Author(s):  
Yong Yang ◽  
Kazuto Matsukawa ◽  
Ho Choi ◽  
Yoshiaki Nakano

This article presents an experimental program to further verify the arch resistance model, which was proposed for evaluating the residual axial capacities of shear-damaged reinforced concrete columns in part 1 of the companion papers. Three reinforced concrete columns with different transverse reinforcement ratios are designed and tested up to axial collapse under different axial force levels. Based on the experimental results, the transverse reinforcement within the shear-damaged region of the designed specimens is confirmed to be able to fully develop their strength at axial collapse. With regard to the evaluation of residual axial capacities, when the damage pattern of the concrete core is consistent with that described in the proposed model, the residual axial capacity of the column along with the included two contributions of the concrete core and longitudinal bars are estimated with a high level of accuracy. When the damage pattern of the concrete core is not completely consistent with that described in the proposed model, although the contribution of the concrete core is not accurately estimated, the contribution of the longitudinal bars is still accurately evaluated. Furthermore, because of the low percentage of the contribution of the concrete core, the damage pattern of the concrete core has little effect on the evaluation accuracy of the residual axial capacity of the column. Thus, using the proposed model, the residual axial capacities of the columns with slightly different damage patterns of the concrete core are still estimated with a high accuracy in this experimental program.


2004 ◽  
Vol 31 (5) ◽  
pp. 846-859 ◽  
Author(s):  
Kenneth J Elwood

Experimental research and post-earthquake reconnaissance have demonstrated that reinforced concrete columns with light or widely spaced transverse reinforcement are vulnerable to shear failure, and in turn, axial failure during earthquakes. Based on experimental data, failure surfaces have been used to define the onset of shear and axial failure for such columns. After the response of the column intersects the failure surface, the shear or axial strength of the column begins to degrade. This paper introduces a uniaxial material model that incorporates the failure surfaces and the subsequent strength degradation. When used in series with a beam-column element, the uniaxial material model can adequately capture the response of reinforced concrete columns during shear and axial load failure. The performance of the analytical model is compared with results from shake table tests.Key words: shear failure, axial failure, beam-column elements, failure surface, earthquakes, reinforced concrete, columns, collapse, structural analysis.


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