Abstract
This research concentrates on the axial load behaviour of circular, square and rectangular concrete filled steel tube (CFST) columns incorporating high-performance self-consolidating concretes such as ultra-high strength concrete (UHSC), engineered cementitious composite (ECC), lightweight concrete (LWC), and crumb rubber concrete (CRC). Seventy-four CFST specimens with varying slenderness, shape, concrete type and presence of internal bar reinforcements are tested experimentally under axial compression loading. The effect of these variables on axial load-deformation response, strain characteristics, failure modes, concrete confinement and axial strength are evaluated through experimental results. Performance of existing analytical/code based models for axial strength and concrete confined strength is evaluated. Concretes without coarse aggregates including UHSC proved less effective at enhancing axial strength of filled tube columns through confinement. In contrast, confinement in filled steel tube columns was found most effective with the use of concretes with coarse aggregates such as LWC and CRC.
Highlights
Concrete-filled steel tubes (CFST) are composite columns made of structural hollow sections
lightweight concrete (LWC)-filled tube columns were found capable of achieving axial capacity comparable to concrete filled steel tube (CFST) columns in-filled with normal concrete (NC)
Calculated values for confined concrete strength and axial capacity of CFST columns using analytical and code-based design equations are compared with experimental values
Summary
Concrete-filled steel tubes (CFST) are composite columns made of structural hollow sections. Tube thickness, diameter, breadth, and depth of CFST columns are denoted by L, t, D, b, and d, respectively. We present analytical models for axial strength of CFST columns and concrete confinement based on the work of previous authors and current research. Analytical equations are based on the biaxial model, which is used to describe stress in the steel tube of filled columns. Besides explaining analytical models for concrete confinement and axial strength, available code provisions are presented These models will be used to compare theoretical concrete confined strength and axial capacity of filled steel tube columns, which will be presented in the chapter. The von-Mises failure criterion given in Eq 4.1 was considered applicable for modelling steel yielding under axial and hoop stresses (σa and σh, respectively) (Hossain 2003b; McAteer et al, 2004; Lachemi et al, 2006b):
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
