Concrete filled double circular steel tube (CFDCST) stub columns

et al. 2019

Engineering Structures

Square concrete-filled double steel tubular (CFDST) beam-columns consisting of an internal circular steel tube have increasingly been utilized in composite building structures because of their high structural performance. This paper describes experimental and numerical studies on the structural responses of square thin-walled CFDST columns loaded eccentrically. Tests on twenty short square CFDST columns were undertaken that included sixteen columns under eccentric loading and four columns under concentric loading. The parameters examined in the experiments included the cross-sectional dimensions, the width-to-thickness ratios of outer and internal tubes and loading eccentricity. The measured ultimate strengths, load-shortening responses, load-lateral displacement curves, stress-strain curves and observed failure modes are presented. A numerical model incorporating the fiber analysis is developed that predicts the moment-curvature responses and axial load-moment strength envelopes of CFDST columns.

Section: Introductionmentioning

confidence: 99%

Experimental and numerical studies of square concrete-filled double steel tubular short columns under eccentric loading

et al. 2019

Engineering Structures

“…Experimental results showed that the outer tube of a circular CFDST column was forced to buckle locally outward and the sandwiched concrete crushed where the steel tube buckled [6,11,12]. The finite element analyses on circular CFST and CFDST columns conducted by Chang et al [21] indicated that the longitudinal compressive stress in the core-concrete in the circular CFDST column was higher than that in the corresponding concrete in the CFST column.…”

Section: Confining Pressure Model For Sandwiched Concretementioning

confidence: 99%

“…In comparisons with experimental studies on CFST columns, only limited experimental investigations on CFDST columns with circular sections were performed by researchers, such as Xiong et al [6], Peng et al [8], Liew and Xiong [9], Romero et al [10], Wan and Zha [11], Ekmekyapar and Al-Eliwi [12]and Ibañez et al [13]. Peng et al [8] Experimental observations indicated that the column ultimate strengths were reduced by increasing the / o o D t ratios of the outer tube.…”

Section: Introductionmentioning

confidence: 99%

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Numerical analysis of axially loaded circular high strength concrete-filled double steel tubular short columns

et al. 2019

Thin-Walled Structures

“…Computational and experimental investigations on the responses of circular short CFDST columns subjected to axial loading have been undertaken by researchers, such as Peng et al [9], Hassanein et al [10], Wan and Zha [11], Xiong et al [12], and Ekmekyapar and Al-Eliwi [13].…”

Section: Introductionmentioning

confidence: 99%

Nonlinear analysis of rectangular concrete-filled double steel tubular short columns incorporating local buckling

et al. 2018

Engineering Structures

Rectangular concrete-filled double steel tubular (CFDST) columns with inner circular steel tube possess higher structural performance than conventional concrete-filled steel tubular (CFST) columns. However, the local buckling of the outer steel tube of thin-walled rectangular CFDST columns has not been accounted for in the existing fiber element models and design codes that may overestimate the column ultimate axial strengths. This paper describes a computationally efficient fiber-based modeling technique developed for determining the behavior of concentrically-loaded rectangular CFDST short columns including the local buckling effects of the external steel tube and the confinement offered by the internal circular steel tube. The effective width concept is used to simulate the post-local buckling of the outer steel tube. Comparative studies are undertaken to verify the fiber-based model with the relevant test results. The computational model is then employed to investigate the axial load-strain responses of rectangular CFDST short columns with various key design variables. A design equation is developed for computing the ultimate axial loads of short rectangular CFDST columns and compared with design methods given in several international design codes. It is shown that the fiber-based modeling technique and the proposed design model predict well the structural performance of short CFDST columns.