Experimental investigation on lightweight concrete-filled cold-formed elliptical hollow section stub columns

Zhang

Journal of Constructional Steel Research

et al. 2017

An experimental programme was conducted to investigate the compressive behaviour of concrete-filled cold-formed steel tubular (CFCFST) stub columns with thicker tubes. A total of 30 CFCFST stub columns were tested. The cold-formed square hollow section (SHS) tubes included unstiffened sections and longitudinally inner-stiffened sections using different stiffening methods. Two tubular thicknesses of 6mm and 10mm were considered. The overall nominal dimension of the steel section was 200×200mm, and the length of the stub columns was 600mm. Normal concrete and self-consolidating concrete with a nominal compressive strength of 30MPa were used to fill the cold-formed SHS steel tubes. The effects of the stiffeners on the rigidity, ductility, failure mode and average sectional strength of the CFCFST specimens were examined. The measured strengths of the CFCFST specimens were also compared with the predicted capacities using methods in various codes including AISC, BS5400, EC4, and DBJ and from a finite element (FE) analysis. Results demonstrate that the inner stiffeners affect the deformability, failure mode and overall strength of the stub columns with the 6mm-thick tubes more significantly. The DBJ code method is comparatively the best in predicting the strength capacity. Using the validated FE model, an extended analysis has been conducted and this has provided further insight into the mechanical behavior of the CFCFST specimens.

Section: Introductionmentioning

confidence: 99%

Experimental study of concrete filled cold-formed steel tubular stub columns

Zhang

Journal of Constructional Steel Research

et al. 2017

Advances in Structural Engineering

“…The calculated ultimate strengths from equation (7) were further compared with the experimental data obtained from Yang et al (2008), Zhao and Packer (2009), Jamaluddin et al (2013), Zha et al (2013), Chan et al (2015), McCann et al (2015, Wu (2015), Liu et al (2017), and Yi and Young (2017). As shown in Figure 13, the average N uc to N ut ratio 0.969 is with the COV of 0.095.…”

Section: Proposed Model For Compressive Capacitymentioning

confidence: 99%

“…Experiments on ECFST stub columns under axial compression have been conducted recently, such as Yang et al (2008), Zhao and Packer (2009), Jamaluddin et al (2013), and Chan et al (2015). They provided the test results of ECFST stub columns with a single aspect ratio ( a = b = 2.0).…”

Section: Introductionmentioning

confidence: 99%

Cold-formed elliptical concrete-filled steel tubular columns subjected to monotonic and cyclic axial compression

Sun

2019

Concrete-filled steel tubular columns are widely used in structural systems, and elliptical concrete-filled steel tubular columns are receiving more and more attention. An experimental study on cold-formed elliptical concrete-filled steel tubular stub columns was carried out under monotonic and cyclic axial compression. The failure modes, axial load–displacement curves, ultimate loads, hoop strain–axial strain behavior, strength deterioration, and residual deformation were obtained and discussed. Complementary finite element models considering the complex non-uniform confinement between steel tube and concrete were developed and validated by experimental results. Then, the validated FE model was used to study the influence of aspect ratio, yield strength of steel, and compressive strength of concrete on the axial capacity of elliptical concrete-filled steel tubular stub columns. Finally, a relatively simple superposition method was put forward to predict the axial bearing capacity of elliptical concrete-filled steel tubular stub columns. Compared with the test data, both the numerical method and superposition method can generate accurate predictions.

Advances in Structural Engineering

“…Concrete-filled steel tubes (CFST) have been widely used in practice due to their well-known advantages, such as high strength, good ductility and easy construction (Han et al, 2014). The mechanical merits of CFST structures mainly rely on the interaction between the outer steel tube and the inner concrete (Aslani et al, 2017; Chan and Huai, 2015; Ellobody and Young, 2006; Han et al, 2014; Lam and Gardner, 2008; Maghub et al, 2017; Roeder et al, 1999; Tao et al, 2016; Uy et al, 2011; Xiong et al, 2017), where the steel tube provides strong confinement for the core concrete to improve its compressive strength and plasticity, while the concrete offers support for the steel tube to relieve its local buckling (Han et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Cyclic performance of circular concrete-filled steel tubular members with initial gap between tube and concrete core

Liao

Zhang

Huang

2019

It is common that initial gaps exist between the steel tube and the core concrete in concrete-filled steel tubular structural members, which might affect the performance of the structure. This article aims to study the effects of the gaps on the cyclic behaviour of circular concrete-filled steel tubular members. A total of 24 concrete-filled steel tubular specimens were tested under constant axial load and cyclically lateral loads, where the main testing parameters included the types of gap, the gap ratio, the axial load level and the steel ratio. The failure mode, lateral load versus lateral displacement hysteretic curve and load versus displacement envelope curve of concrete-filled steel tubular specimens with pre-designed gaps were experimentally investigated and compared with those of the reference ones without any gap. The effects of gaps on the ultimate strength, ductility and dissipated energy of the concrete-filled steel tubular members were quantitatively evaluated according to the test results. The influence of gaps on circular concrete-filled steel tubes under different loading conditions, such as axial compressive loading, pure bending, eccentrically compressive loading and cyclic lateral loading, was also compared and discussed.