• Steel and Composite Structures
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• v.17 no.5
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• pp.667-686
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• 2014

Tapered concrete filled double skin steel tubular (CFDST) columns have been used in China for structures such as electricity transmission towers. In practice, the bearing capacity related to the connection details on the top of the column is not fully understood. In this paper, the experimental behaviour of tapered CFDST stub columns subjected to axial partial compression is reported, sixteen specimens with top endplate and ten specimens without top endplate were tested. The test parameters included: (1) tapered angle, (2) top endplate thickness, and (3) partial compression area ratio. Test results show that the tapered CFDST stub columns under axial partial compression behaved in a ductile manner. The axial partial compressive behaviour and the failure modes of the tapered CFDST stub columns were significantly influenced by the parameters investigated. Finally, a simple formula for predicting the cross-sectional capacity of the tapered CFDST sections under axial partial compression is proposed.

• Computers and Concrete
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• v.9 no.6
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• pp.403-426
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• 2012

This paper deals with the structural behaviour of tapered concrete-filled steel composite (TCFSC) columns under eccentric loading. Finite element software LUSAS is used to perform the nonlinear analyses to predict the structural behaviour of the columns. Results from the finite element modelling and existing experimental test are compared to verify the accuracy of the modelling. It is demonstrated that they correlate reasonably well with each other; therefore, the proposed finite element modelling is absolutely accurate to predict the structural behaviour of the columns. Nonlinear analyses are carried out to investigate the behaviour of the columns where the main parameters are: (1) tapered angle (from $0^{\circ}$ to $2.75^{\circ}$); (2) steel wall thickness (from 3 mm to 4 mm); (3) load eccentricity (15 mm and 30 mm); (4) L/H ratio (from 10.67 to 17.33); (5) concrete compressive strength (from 30 MPa to 60 MPa); (6) steel yield stress (from 250 MPa to 495 MPa). Results are depicted in the form of load versus mid-height deflection plots. Effects of various tapered angles, steel wall thicknesses, and L/H ratios on the ultimate load capacity, ductility and stiffness of the columns are studied. Effects of different load eccentricities, concrete compressive strengths and steel yield stresses on the ultimate load capacity of the columns are also examined. It is concluded from the study that the parameters considerably influence the structural behaviour of the columns.