Comparative study of square stirrup-confined concrete-filled steel tubular stub columns under axial loading

Ding, Fa‐xing; Lu, Deren; Bai, Yu; Zhou, Qishi; Ni, Ming; Yu, Zhenkun; Jiang, Guo-shuai

doi:10.1016/j.tws.2015.10.018

Cited by 79 publications

(19 citation statements)

References 15 publications

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“…It can be seen from Figures 8A,B that the axial stress (σ L,s ) and transverse stress (σ θ,s ) of the midpoint and endpoint of the middle section of steel tube intersect one another after the steel tube yielding, wherein the axial stress and the transverse stress of the stub columns with the steel ratio of 0.04 is the earliest intersect, followed by stub columns with the steel ratio of 0.02 and 0.05, and finally the stub columns with steel ratios of 0.06 and 0.08, which shows that the stub columns with a steel ratio less than 0.05 example has obvious confinement effect on the core concrete; Refer to the equivalent concrete lateral compression stress concept and calculation method proposed in the reference (Ding et al, 2018). The calculation diagram of core concrete in the limit state is shown in Figure 9.…”

Section: Steel Ratiomentioning

confidence: 97%

Experimental Study of Square CFST Stub Columns With a Low Steel Ratio Under Axial Loading

Gong

Ding

et al. 2021

Front. Mater.

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This paper presents an experimental and numerical study on large dimension concrete-filled square low steel ratio steel tubular (CFST) stub columns under axial loading. Four specimens were designed to investigate the effects of steel ratio on the confinement effect of square CFST stub columns with a low steel ratio. ABAQUS was used to establish 3D finite element (FE) models for simulation of square CFST stub columns with a low steel ratio under axial loading. Furthermore, based on the experimental verification, the definition of the confinement index (ϕ = fsAs/(fcAc)) was discussed and the effect of the grade of concrete and steel tube was also investigated. With the same cross-sectional dimensions, the confinement effect of the square CFST stub columns with a low steel ratio (less than 0.05) was better than the others. The stub columns with the yield strength of steel tube fs = 235 MPa (345, 420 MPa) and compressive cubic strength of concrete fcu = 40 MPa (60, 80 MPa) can give fully demonstrate the material performance and reflect the better confinement effect. Based on the experimental results and FE modeling, a practical calculation formula for the ultimate load-carrying capacity of square CFST stub columns with a low steel ratio was proposed. The formula calculation results presented in this paper show good agreement with the experimental results. Compared with the existing formulas, the proposed formula has better precision.

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Section: Steel Ratiomentioning

confidence: 97%

Experimental Study of Square CFST Stub Columns With a Low Steel Ratio Under Axial Loading

Gong

Ding

et al. 2021

Front. Mater.

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“…According to Yu et al [18], an increase in the Poisson's ratio indicates increased confinement effect of the concrete core offered by the steel tube. Karimi et al [19] and Ding et al [1] stated that the Poisson's ratio is an important parameter for evaluating confinement effectiveness. The core concrete continually expands under loading, and the steel tube and stirrups constrain the expansion of the concrete due to confinement effect.…”

Section: Poisson's Ratiomentioning

confidence: 99%

“…Circular tube shows best confinement to the core concrete of CFT columns. However, the thickness of the steel tube is limited due to weldability and construction concerns for large-diameter CFT columns [1]. In order to improve the mechanical performance of CFT columns without increasing the wall thickness of the steel tube, various methods have been proposed.…”

mentioning

confidence: 99%

“…Therefore, using relatively thin steel tube combined with welded stirrups on the steel tube could be an alternative method. Ding [1] studied square stirrup-confined CFT stub columns with cross ties, spiral, and rhombus stirrups. The results showed that welding bidirectional stirrups to the inner surface of the steel tube is the most efficient way in reinforcing square CFT stub columns.…”

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confidence: 99%

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Comparative study of stirrup-confined circular concrete-filled steel tubular stub columns under axial loading

Ding

Zhu

Cheng

et al. 2018

Thin-Walled Structures

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This paper presents a comparative study of circular concrete-filled steel tubular stub columns with three different stirrup confinement types: bidirectional stirrups, loop stirrups and orthogonal stirrups. Axial compression tests have been carried out aiming at investigating the effects of the stirrup form and volume-stirrup ratio on the mechanical behavior of the stirrup-confined circular CFT stub columns, and ABAQUS was used to carry out the 3D numerical modelling. Radial stress of the core concrete and the composite action among the steel tube, stirrups and the core concrete have been investigated. It is found that the confinement provided by stirrups on core concrete strongly outperforms that provided by steel tube, steel sections or steel reinforcement. Furthermore, a simplified approach was developed to predict the ultimate bearing capacity of stirrup-confined circular CFT stub columns, which agreed well with the experimental and numerical results.

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“…The steel tube can not only be served as permanent formwork but also provide welldistributed confinement to the core concrete, whereas the core concrete delays or prevents the tube's local buckling and forces the tube to buckle outwards rather than inwards. In recent years, Lai and Ho [1,2], Ding et al [3,4], Wang et al [5], and Teng et al [6] have proposed a series of confining schemes (e.g., external rings, stirrups, stiffeners, and FRP) to further improve the load bearing capacity and ductility of the CFST columns in compression. Meanwhile, a measure to enhance the performance of the CFST columns (i.e., under the premise of keeping the same amount of steel, reducing the wall thickness of the steel tube, simultaneously arranging steel stirrups in the tube, and a gap between the tube and the stirrups being left) has also been proposed by the authors.…”

Section: Introductionmentioning

confidence: 99%

10.28: Fire performance of concrete filled steel tubular columns with built‐in stirrups

Zang

Zhang³

2017

ce papers

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Two concrete filled steel tubular columns with built-in stirrups (i.e., Specimens 1 and 2) and one control column (i.e., concrete filled steel tubular column without built-in stirrups, Specimen 3) were exposed to the ISO834 standard fire, and fire behaviors of the three columns were investigated and compared with each other. The steel usage of Specimen 1 (2) (i.e., total weight of the steel tube and stirrups) was the same as that of Specimen 3 (i.e., weight of the steel tube). The distance between the stirrup's centerline and inner surface of the steel tube was 20mm for Specimen 1, and 50mm for Specimen 2. The height and outer diameter of all the three columns were, respectively, 3800mm and 320mm. The axial load applied to Specimens 1 and 2 was identical with that applied to Specimen 3. Test results show that when the steel usage keeps unchanged, the fire endurance of the concrete filled steel tubular column with built-in stirrups is much longer than that of the column without built-in stirrups. Finally, a finite element analysis (FEA) model was developed and verified against the experimental results, and a parametric study has been preliminarily performed to reveal the fire performance of the concrete filled steel tubular columns with built-in stirrups.Keywords: concrete filled steel tube, fire performance, built-in stirrup 2 EXPERIMENTAL PROGRAM Specimen preparation and material propertiesSchematic diagrams of two CFST columns with built-in stirrups (Specimen 1 and Specimen 2) and one conventional CFST column (Specimen 3, control specimen) are shown in Fig. 1. All the three

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Comparative study of square stirrup-confined concrete-filled steel tubular stub columns under axial loading

Cited by 79 publications

References 15 publications

Experimental Study of Square CFST Stub Columns With a Low Steel Ratio Under Axial Loading

Experimental Study of Square CFST Stub Columns With a Low Steel Ratio Under Axial Loading

Comparative study of stirrup-confined circular concrete-filled steel tubular stub columns under axial loading

10.28: Fire performance of concrete filled steel tubular columns with built‐in stirrups

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