Experimental and Analytical Study on Local Buckling Behavior of the Concrete-filled Thin-walled Welded Steel Columns (original) (raw)
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Local buckling of steel plates in concrete-filled thin-walled steel tubular beam–columns
Journal of Constructional Steel Research, 2007
The availability of high strength steels and concrete leads to the use of thin steel plates in concrete-filled steel tubular beam–columns. However, the use of thin steel plates in composite beam–columns gives a rise to local buckling that would appreciably reduce the strength and ductility performance of the members. This paper studies the critical local and post-local buckling behavior of steel plates in concrete-filled thin-walled steel tubular beam–columns by using the finite element analysis method. Geometric and material nonlinear analyses are performed to investigate the critical local and post-local buckling strengths of steel plates under compression and in-plane bending. Initial geometric imperfections and residual stresses presented in steel plates, material yielding and strain hardening are taken into account in the nonlinear analysis. Based on the results obtained from the nonlinear finite element analyses, a set of design formulas are proposed for determining the critical local buckling and ultimate strengths of steel plates in concrete-filled steel tubular beam–columns. In addition, effective width formulas are developed for the ultimate strength design of clamped steel plates under non-uniform compression. The accuracy of the proposed design formulas is established by comparisons with available solutions. The proposed design formulas can be used directly in the design of composite beam–columns and adopted in the advanced analysis of concrete-filled thin-walled steel tubular beam–columns to account for local buckling effects.
Journal of Constructional Steel Research, 2015
This paper presents an efficient mathematical model for studying the global buckling behavior of concrete-filled steel tubular (CFST) columns with compliant interfaces. The present mathematical model is used to evaluate exact critical buckling loads and modes of CFST columns for the first time. The results prove that the presence of finite interface compliance may significantly reduce the critical buckling load of CFST columns. A good agreement between analytical and experimental buckling loads of circular CFST columns is obtained if at least one among longitudinal and radial interfacial stiffnesses is high. The design methods compared in the paper give conservative results in comparison with the experimental results and analytical results for almost perfectly bonded layers. The parametric study reveals that critical buckling loads of CFST columns are very much affected by the diameter-to-depth ratio and concrete elastic modulus. Moreover, a material nonlinearity has a pronounced effect for short CFST columns, and a negligible effect for slender ones.
Buckling performance of thin-walled filled steel columns
Turkish journal of engineering, 2023
Axial load Buckling Column FEA Concrete-filled composite elements have recently gained popularity as beams and columns all over the world. They have advantages similar to reinforced concrete elements, such as the moulding process and the lack of maintenance of the filled concrete, as well as advantages similar to hollow steel elements, such as enhancing compressive strength and bending capacity by using smaller sections. In this paper, the buckling behaviour of thin-walled steel columns with circular cross-section and different filling materials was investigated under uniaxial load. Six different materials (concrete produced using normal aggregate, concrete produced using waste aggregate, waste fine aggregate, waste coarse aggregate, waste iron dust and polyurethane) were used as filling. Filled columns were compared experimentally with hollow thin-walled steel columns that had the same height and diameter. All specimens had the same length (750 mm), same diameter (60.3mm) and the same wall thickness (3mm). Experimental results were compared with analytical results obtained from a calculation done using the national steel design code, Design, Calculation and Construction Principles of Steel Structures 2016. Additionally, columns specimens were modelled in Abaqus software. Conservative and consistent results were obtained from comparing experimental, analytical, and numerical results.
A novel steel section for concrete-filled tubular columns
Thin-walled Structures, 2008
The strength performance of three joints with T-section concrete filled steel tubular columns and I-section steel beams, one of which is all-welded joint and the other two are joints with welded flanges and bolted webs, are studied in this paper. Hysteretic curves and skeleton curves are acquired from experiments. Besides, deformation behaviors, reduction of strength performance and energydissipation capacity are analyzed. Results show that these joints have good hysteretic performance and energy-dissipation capacity. The quality of welding between beams and sleeves and plug welding between sleeves and columns has great impact on the strength performance of joints, as well as deformation behaviors and energy-dissipation capacity. The number of plug welding influences strength performance, while the quality of welding influences energy-dissipation capacity. Finite element models are established. Results of finite element analysis show good agreement with experimental results, which indicates that these finite element models can be used for parameters analysis.
An experimental behaviour of concrete-filled steel tubular columns
Journal of Constructional Steel Research, 2005
In this paper results of tests conducted on 27 concrete-filled steel tubular columns are reported. The test parameters were the column slenderness, the load eccentricity covering axially and eccentrically loaded columns with single or double curvature bending and the compressive strength of the concrete core. The test results demonstrate the influence of these parameters on the strength and behaviour of concrete-filled steel tubular columns. A comparison of experimental failure loads with the predicted failure loads in accordance with the method described in Eurocode 4 Part 1.1 showed good agreement for axially and eccentrically loaded columns with single curvature bending whereas for columns with double curvature bending the Eurocode loads were higher and on the unsafe side. More tests are needed for the case of double curvature bending.
Buckling of Slender Concrete-Filled Steel Tubes with Compliant Interfaces
Latin American Journal of Solids and Structures
This paper presents an exact model for studying the global buckling of concrete-filled steel tubular (CFST) columns with compliant interfaces between the concrete core and steel tube. This model is then used to evaluate exact critical buckling loads and modes of CFST columns. The results prove that interface compliance can considerably reduce the critical buckling loads of CFST columns. A good agreement between analytical and experimental buckling loads is obtained if at least one among longitudinal and radial interfacial stiffnesses is high. The parametric study reveals that buckling loads of CFST columns are very much affected by the interfacial stiffness and boundary conditions.
Analysis of Concrete-Filled Steel Tubular Beam-Columns
The elastic-plastic behavior of pin-ended, concretefilled steel tubular columns, loaded either symmetrically or unsymmetrically about either of the two axes is studied using the Column Curvature Curve method. Two types of cross section are considered: circular shapes and square shapes. Three types of stress-strain relationship for concrete are studied:
Performance of Concrete Filled Steel Tubular Columns
Recent advancements in the availability of higher strength steels, better coating materials for protection and high strengths/performance concretes have expanded the scope of concrete filled steel composite columns with wide ranging applications in various structural systems with ease of construction, highly increased strengths and better performance. This experimental study is carried out on the behavior of short, concrete filled steel tubular columns axially loaded in compression to failure. Three dimensional confinement effect of concrete along with support provided by concrete to the thin walls of steel tube to prevent local buckling had a composite effect on the strength of the composite column increasing the compressive strengths by almost 300 to 400%. In addition to the concrete core, the parameters for the testing were shape of the steel tube and its diameter-to-thickness ratio. It has been observed that ultimate strength of concrete filled steel tubes under concentric compression behavior is considerably affected by the thickness of the steel tube, as well as by the shape of its cross section. Confining effect in circular CFST columns improves their strength, appreciably. The axial load-deformation behavior of columns is remarkably affected by the cross-sectional shape, diameter/width-to-thickness ratio of the steel tube, and the strength of the filled concrete. The load deformation relationship for circular columns showed strain-hardening or elastic perfectly plastic behavior after yielding.
Parametric Study on the Behavior of Steel Tube Columns with Infilled Concrete—An Analytical Study
Sustainability
Concrete-filled steel tube (CFST) columns are used in tall buildings and bridges, and they provide more rigidity and higher bearing capacity, but buckling affects their behavior. There is an exceptional need to study the behavior of these columns under various conditions. The numerical method is beneficial in supplementing the experimental works and is used to explore the effects of various parameters because of the limitations in cost, apparatus, and time of the experimental program. The various parameters, such as the different slenderness ratios, i.e., column-height-to-cross-section-dimension (H/D), different steel-tube-thickness-to-column-dimension (D/t), and different compressive strength of concrete to yield strength of steel tube ratio (fc/fy) under concentric axial loading are considered in this current study. Firstly, a finite element model used the “ANSYS” software program and was constructed to validate the results of the experimental works. The extensive numerical models...