Seismic performance of square concrete columns reinforced with grade 600 MPa longitudinal and transverse reinforcement steel under high axial load

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.

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Shear Strength Model for Reinforced Concrete Columns with Low Transverse Reinforcement Ratios

Advances in Structural Engineering ◽

10.1260/1369-4332.17.10.1373 ◽

2014 ◽

Vol 17 (10) ◽

pp. 1373-1385 ◽

Cited By ~ 1

Author(s):

Cao Thanh Ngoc Tran ◽

Bing Li

Keyword(s):

Shear Strength ◽

Reinforced Concrete ◽

Axial Load ◽

Concrete Columns ◽

Transverse Reinforcement ◽

Reinforced Concrete Column ◽

Reinforced Concrete Columns ◽

Existing Structures ◽

Reversed Cyclic ◽

Constant Axial Load

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

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Seismic Behavior of Concrete Columns Confined by CFRP and GFRP Jackets

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.405-408.657 ◽

2013 ◽

Vol 405-408 ◽

pp. 657-663

Author(s):

Yu Mei Teng ◽

Ye Tian ◽

James Liu

Keyword(s):

Tensile Strength ◽

Seismic Performance ◽

Axial Load ◽

Seismic Behavior ◽

Large Scale ◽

Concrete Columns ◽

Cyclic Displacement ◽

Transverse Steel ◽

The Moment ◽

Constant Axial Load

This paper presents experimental results of a series of large-scale reinforced concrete circular and square columns tested under lateral cyclic displacement excursions while simultaneously subjected to constant axial load. All the specimens contained only minimal transverse steel and were then retrofitted with CFRP or GFRP jackets except control specimens. The measured hysteretic loops of the moment vs. curvature and shear vs. deflection relationships are reported for each specimen. It was observed that both CFRP and GFRP wrapping could provide effective confinement and significantly improve the seismic performance of columns. The effectiveness of FRP in enhancing column ductility relates more closely to its tensile strength than stiffness, thus the application of GFRP confinement to concrete columns is promoted due to obtainability and economical concern.

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Behavior of Square RC Short Columns with New Arrangement of Ties Subjected to Axial Load: Experimental and Numerical Studies

Periodica Polytechnica Civil Engineering ◽

10.3311/ppci.19369 ◽

2022 ◽

Author(s):

Hazem Elbakry ◽

Tarek Ebeido ◽

El-Tony M. El-Tony ◽

Momen Ali

Keyword(s):

Reinforced Concrete ◽

Axial Load ◽

Concrete Columns ◽

Experimental Program ◽

Transverse Reinforcement ◽

Reinforcing Bars ◽

Rc Columns ◽

Reinforced Concrete Columns ◽

Short Columns ◽

Numerical Studies

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.

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Study on the Factors Affecting the Anti-Seismic Performance of Steel Reinforced High-Strengh Concrete Columns

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.535-537.1842 ◽

2012 ◽

Vol 535-537 ◽

pp. 1842-1846

Author(s):

Bao Sheng Yang ◽

Shi Hua Song

Keyword(s):

Seismic Performance ◽

High Strength Concrete ◽

Axial Load ◽

Seismic Behavior ◽

Influencing Factor ◽

High Strength ◽

Concrete Columns ◽

Factors Affecting ◽

Strength Concrete ◽

High Strength Concrete Columns

Through experimental study of six steel reinforced high strength concrete columns under low cyclic horizontal loads, the influence on anti-seismic behavior of the columns under different axial load coefficient, stirrup ratio and steel reinforced form is analyzed.The study found in addition to the fact that the anti-seismic performance of high strength concrete columns is sensitive to axial load coefficient, steel reinforced form is also an important influencing factor. For high strength concrete columns with different steel reinforced forms, appropriate adjustment of its axial load coefficient may be carried out, however the influence of stirrup ratio is very little on anti-seismic performance of columns.

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Analytical Estimation of the Residual Drift of Reinforced Concrete Columns under the Ultimate Displacement Capacity

Periodica Polytechnica Civil Engineering ◽

10.3311/ppci.16386 ◽

2020 ◽

Author(s):

Sinan Cansız

Keyword(s):

Reinforced Concrete ◽

Axial Load ◽

Concrete Columns ◽

Load Level ◽

Transverse Reinforcement ◽

Longitudinal Reinforcement ◽

Reinforced Concrete Columns ◽

Residual Drift ◽

Drift Ratio ◽

Ultimate Displacement

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.

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