Comparative strength analyses of structural concrete columns

2006 ◽  
Vol 33 (6) ◽  
pp. 735-747
Author(s):  
Sher Ali Mirza
Keyword(s):  
Reinforced Concrete ◽  
Computational Methods ◽  
Slenderness Ratio ◽  
Concrete Strength ◽  
Concrete Columns ◽  
Normal Density ◽  
Structural Concrete ◽  
Composite Columns ◽  
Physical Tests ◽  
Composite Steel

A comparative study was undertaken of selected computational methods for predicting the strength determined from more than 500 physical tests of rectangular, tied structural concrete columns available in the literature. The study included 354 reinforced concrete and 150 composite steel–concrete columns. The computational methods compared were those of CSA A23.3-94 and Eurocode 2 for reinforced concrete and those of CSA A23.3-94 and Eurocode 4 for composite columns. The physical tests used for comparison were conducted on columns that were braced, pinned at both ends, subjected to short-term loads, and constructed using normal-density concrete with a compressive strength between approximately 17 and 57 MPa. Major variables included the concrete strength, the end eccentricity ratio, the slenderness ratio, the longitudinal reinforcing steel index for reinforced concrete or the structural steel index for composite columns, and the transverse reinforcement (tie/hoop) volumetric ratio. The study provided insights into the reliability of the computational methods examined. Recommendations for improving the CSA A23.3-94 procedure for the design of reinforced concrete and composite steel–concrete columns are also presented.Key words: columns, composite construction, computations, physical tests, reinforced concrete, reliability, strength.

scholarly journals Examination of Strength Modeling Reliability of Physical Tests on Structural Concrete Columns

2011 ◽  
Vol 2011 ◽  
pp. 1-16 ◽  
Author(s):  
Sher Ali Mirza
Keyword(s):  
Axial Force ◽  
Slenderness Ratio ◽  
Concrete Strength ◽  
Concrete Columns ◽  
American Concrete Institute ◽  
Normal Density ◽  
Structural Concrete ◽  
Composite Columns ◽  
Physical Tests ◽  
Computational Procedures

Comparisons and analyses of strengths from selected computational procedures were undertaken of more than 500 physical tests of rectangular, tied, structural concrete columns reported in the published literature. The computational procedures compared with the physical tests and with each other include a commercially available nonlinear finite element modeling software and the Canadian Standards Association (CSA) Standard A23.3-04. The requirements of the American Concrete Institute (ACI) 318-08 are very similar to those of the CSA A23.3-04, and hence, strength comparisons and analyses reported here are also applicable to ACI 318-08. The physical tests used for comparison were conducted on columns that were braced and pinned at both ends and were constructed using normal-density concrete with a compressive strength between approximately 17 and 57 MPa. The columns were subjected to short-term loads producing pure axial force, axial force combined with symmetrical single-curvature bending, or pure bending. Major variables included the concrete strength, the end eccentricity ratio, the slenderness ratio, the longitudinal reinforcing steel index for reinforced concrete or the structural steel index for composite columns, and the transverse reinforcement (tie/hoop) volumetric ratio. The study provides an examination of the reliability of the computational methods examined.

Loading Process Simulation of GFRP Tube Filled with Steel-Reinforced High-Strength Concrete Columns Subjected to Eccentric Compression

2011 ◽  
Vol 71-78 ◽  
pp. 4203-4206
Author(s):  
Le Zhou ◽  
Hong Tao Liu
Keyword(s):  
High Strength Concrete ◽  
Slenderness Ratio ◽  
Concrete Strength ◽  
High Strength ◽  
Concrete Columns ◽  
Composite Columns ◽  
Strength Concrete ◽  
Finite Strip Method ◽  
Eccentric Compression ◽  
High Strength Concrete Columns

For the further study of bearing compressive capacity of GFRP tube filled with SHC（steel-reinforced high-strength concrete）columns subjected to eccentric compression, and analysis its whole bearing compressive process under eccentric compression. Based on the flat section assumption finite strip method, the calculating program of bearing eccentric compressive capacity of GFRP tube filled with SHC columns is proposed according to existing retrofit theory and related technical procedures. The relation curves of load-deformation is gotten using this calculating program, at the same time it can get the effect curves of concrete strength, slenderness ratio, eccentricity and containing bone rate to load-deformation. Calculations show that the ultimate bearing compressive capacity of composite column decreases with the increase of slenderness ratio, and elastic stage of component curve gradually shortens and stiffness gradually loses; The ultimate bearing compressive capacity of composite columns decreases with the increase of eccentricity; component ductility improves; the ultimate bearing compressive capacity of composite columns increases with the increase of concrete strength. The calculated results agree well with the experimental results and this study provides a basis for practical design.

Effective flexural stiffness of slender structural concrete columns

2008 ◽  
Vol 35 (4) ◽  
pp. 384-399 ◽  
Author(s):  
Timo K. Tikka ◽  
S. Ali Mirza
Keyword(s):  
Reinforced Concrete ◽  
Full Range ◽  
Strain Curve ◽  
Bending Moment ◽  
Concrete Columns ◽  
Flexural Stiffness ◽  
Column Length ◽  
Stress Strain Curve ◽  
Structural Concrete ◽  
Composite Steel

The CSA A23.3 standard permits the use of a moment-magnifier approach for the design of slender reinforced concrete and composite steel–concrete columns. This approach is strongly influenced by the effective flexural stiffness (EI), which varies due to the nonlinearity of the concrete stress–strain curve and the cracking along the column length, among other factors. The EI equations given in the CSA standard are approximate when compared with the EI values computed from the axial load – bending moment – curvature relationships. This study was conducted to determine the influence of a full range of variables on EI used for the design of slender reinforced concrete and composite steel–concrete columns, and also to examine the existing CSA EI equations. Over 27 000 isolated concrete columns, each with a different combination of specified variables, in symmetrical single-curvature bending were simulated to generate the stiffness data. Two new design equations to compute EI of structural concrete columns were then developed from the simulated stiffness data and are proposed as an alternative to the existing CSA design equations for EI.

Nonlinear Analysis of Eccentric Compression of GFRP Tube Filled with SRHC Columns

2012 ◽  
Vol 476-478 ◽  
pp. 1562-1567
Author(s):  
Le Zhou ◽  
Lian Guang Wang ◽  
Peng Niu ◽  
Hong Bin Nie
Keyword(s):  
Slenderness Ratio ◽  
Concrete Strength ◽  
High Strength ◽  
Concrete Columns ◽  
Composite Columns ◽  
Finite Strip ◽  
Finite Strip Method ◽  
Eccentric Compression ◽  
High Strength Concrete Columns ◽  
Elastic Stage

The whole bearing compressive process under eccentric compression is analyzed for the further study of bearing compressive capacity of GFRP tube filled with SHC（steel-reinforced high-strength concrete）columns subjected to eccentric compression. Based on finite strip method from the plane cross-section assumption, the computation program of bearing eccentric compressive capacity of GFRP tube filled with SHC columns is formulated according to the existing retrofit theory and related technical procedures. The relation curves of load-deformation, as well as the effect curves of concrete strength, slenderness ratio, eccentricity and containing bone rate to load-deformation is obtained by means of this calculating program. Calculations show that the ultimate bearing compressive capacity of composite column decreases with the increase of slenderness ratio, elastic stage of component curve gradually shortens and stiffness gradually loses; The ultimate bearing compressive capacity of composite columns decreases with the increase of eccentricity; component ductility improves; the ultimate bearing compressive capacity of composite columns increases with the increase of concrete strength. The calculated results agree well with the experimental results and provides a basis for practical design

Experimental Investigation on Behavior of Slender Steel Reinforced Concrete Columns Subjected to Eccentric Load

2012 ◽  
Vol 256-259 ◽  
pp. 697-701
Author(s):  
Zhuo Han ◽  
Shao Fei Jiang ◽  
Zhi Ping Sun ◽  
Le Zhou
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Slenderness Ratio ◽  
Concrete Strength ◽  
Axial Loading ◽  
Experimental Investigations ◽  
Eccentric Load ◽  
Composite Columns ◽  
Steel Reinforced Concrete ◽  
Steel Shape

The objectives of this research were to investigate the structural behavior of slender steel reinforced concrete (Referred to as SRC)composite columns subjected to eccentric axial loading. The test consisted of 10 slender columns, with rectangular section160×180mm, and steel shape I10 encased in concrete. The stirrup spacing was 150 mm; its diameter was 6 mm. The diameter of longitudinal reinforcing bars was 10 mm. Details of the experimental investigations including description of the test columns, failure modes and mechanisms, strain characteristics, and load-deformation responses are discussed. Effects of concrete strength, slenderness of columns, and eccentricity of axial loads on the load-carrying capacity of slender column are then presented. Based on these results, a range of slenderness ratio and eccentric ratio of slender SRC column is proposed.

Research on Axial Compression Performance of Steel & Steel Pipe Reinforced Concrete Columns

2014 ◽  
Vol 584-586 ◽  
pp. 1313-1317
Author(s):  
Yun Yun Li ◽  
Bao Sheng Yang
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Concrete Strength ◽  
Concrete Columns ◽  
Steel Pipe ◽  
Shear Cracks ◽  
Working Mechanism ◽  
Factors Affecting ◽  
Composite Columns ◽  
Compression Performance

Through axial load bearing capacity test of eight steel & steel pipe reinforced concrete composite columns, the working mechanism, the ductility and the ultimate bearing capacity of the composite columns were studied, and the main factors affecting the performance of the composite columns are discussed, including concrete strength and the ferrule coefficient. The results show that the collaborative force of steel, steel pipe and concrete can effectively improve the bearing capacity of the columns, delay or inhibit the spread of oblique shear cracks in concrete and improve the ductility of the columns.

scholarly journals Analysis and Modification of Methods for Calculating Axial Load Capacity of High-Strength Steel-Reinforced Concrete Composite Columns

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6860
Author(s):  
Jun Wang ◽  
Yuxin Duan ◽  
Yifan Wang ◽  
Xinran Wang ◽  
Qi Liu
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
High Strength Steel ◽  
Slenderness Ratio ◽  
High Strength ◽  
Confinement Effect ◽  
Test Results ◽  
Composite Columns ◽  
Steel Reinforced Concrete ◽  
Modified Formula

To investigate the applicability of the methods for calculating the bearing capacity of high-strength steel-reinforced concrete (SRC) composite columns according to specifications and the effect of confinement of stirrups and steel on the bearing capacity of SRC columns. The axial compression tests were conducted on 10 high-strength SRC columns and 4 ordinary SRC columns. The influences of the steel strength grade, the steel ratio, the types of stirrups and slenderness ratio on the bearing capacity of such members were examined. The analysis results indicate that using high-strength steel and improving the steel ratio can significantly enhance the bearing capacity of the SRC columns. When the slenderness ratio increases dramatically, the bearing capacity of the SRC columns plummets. As the confinement effect of the stirrups on the concrete improves, the utilization ratio of the high-strength steel in the SRC columns increases. Furthermore, the results calculated by AISC360-19(U.S.), EN1994-1-1-2004 (Europe), and JGJ138-2016(China) are too conservative compared with test results. Finally, a modified formula for calculating the bearing capacity of the SRC columns is proposed based on the confinement effect of the stirrups and steel on concrete. The results calculated by the modified formula and the finite element modeling results based on the confinement effect agree well with the test results.

Experimental Study on Mechanical Properties of Axially Loaded PVC Tubed Short Concrete Columns

2011 ◽  
Vol 99-100 ◽  
pp. 715-718 ◽  
Author(s):  
Jun Dong ◽  
De Ping Chen ◽  
Ju Mei Zhao ◽  
De Shan Shan ◽  
Xin Yue Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carrying Capacity ◽  
Loading Condition ◽  
Concrete Strength ◽  
Concrete Columns ◽  
Load Carrying Capacity ◽  
Composite Columns ◽  
Load Carrying ◽  
Strength And Deformation ◽  
Axially Loaded

Twelve PVC tubed short concrete columns and four columns without PVC tube confined were tested under axial load to investigate mechanical properties of axially loaded PVC tubed short concrete columns . The principal influencing factors such as concrete strength, loading condition and ratio of height to diameter were studied. Test results indicated that strength and deformation performance of core concrete increased as a result of the confinement of PVC tube. The PVC tube confinement effect on concrete will decrease with an increase in strength of concrete. Load- carrying capacity and deformation of short composite columns with different loading condition made some difference. As the ratio of height to diameter increases, load- carrying capacity and plasticity of short composite columns decreased gradually.

SEISMIC PERFORMANCE OF GFRP-RC RECTANGULAR COLUMNS: NUMERICAL STUDY

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ehab El-Salakawy ◽  
Fangxin Ye ◽  
Yasser Mostafa Selmy
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Loading ◽  
Axial Load ◽  
Numerical Study ◽  
Concrete Strength ◽  
Weight Ratio ◽  
Concrete Columns ◽  
Load Level ◽  
Reinforced Concrete Columns ◽  
Rectangular Columns

Composite materials like glass fiber-reinforced polymer (GFRP) is becoming widely acceptable to be used as a reinforcing material due to its high ultimate tensile strength-to-weight ratio and excellent resistance to corrosion. However, the seismic behavior of GFRP-reinforced concrete columns has not been fully investigated yet. This paper presents the results of a numerical analysis of full-size GFRP-RC rectangular columns under cyclic loading. The simulated column depicts the lower part of a building column between the foundation and the point of contra-flexure at the mid-height of the column. GFRP reinforcement properties and concrete modeling based on fracture energy have been incorporated in the numerical model. Experimental validation has been used to examine the accuracy of the constructed finite element models (FEMs) using a commercially available software. The validated FEM was used to perform a parametric study, considering several concrete strength values and axial load levels, to study its influence on the performance of the GFRP-reinforced concrete columns under cyclic loading. It was concluded that the hysteretic dissipation capacity deteriorates under high axial load level due to severe softening of the concrete. The FE results showed a substantial improvement of the lateral load-carrying capacities by increasing concrete compressive strength.

Steel Core in Composite Steel-Concrete Columns

2016 ◽  
Vol 691 ◽  
pp. 195-206
Author(s):  
Juraj Frólo ◽  
Štefan Gramblička
Keyword(s):  
Cross Section ◽  
Design Method ◽  
High Strength ◽  
Concrete Columns ◽  
Steel Tube ◽  
Experimental Investigations ◽  
Composite Columns ◽  
Steel Core ◽  
Composite Steel ◽  
Simplified Design Method

This paper presents some results of theoretical and experimental investigations of composite steel-concrete columns with solid steel profiles - steel cores. Due to absence of simplified design method according to EN 1994-1-1 [1], design of these columns in practice is limited in general. Reasons for this are residual stresses in steel profile caused by fabrication process and limitation of strains in concrete. Recommendations have been determined for simplified design method according to EN 1994-1-1 for composite columns made of high strength concrete filled steel tube with central steel core. Results of experimental research on composite columns with the cross-section made of steel core covered by reinforced concrete are presented.

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