New theoretical model for SSTT-confined HSC columns

Abstract

The concrete-confining method using low-cost steel straps, also known as the steel-strapping tensioning technique (SSTT), has proven to be effective in increasing the load-carrying capacity and ductility of high-strength concrete (HSC). However, the technique is restricted to short columns subjected to concentric loads as most of the studies on the SSTT have focused on concentrically loaded short HSC specimens. The performance of the SSTT in confining eccentrically loaded slender HSC columns is not fully understood due to a scarcity of experimental and theoretical data. Against this background, a theoretical model for analysing slender SSTT-confined cylindrical HSC columns is developed based on a numerical integration method. A previously proposed stress–strain empirical model is employed to develop the theoretical model. The model is used to generate the load–deflection curves and axial load–moment interaction diagrams of SSTT-confined HSC columns. Based on comparisons with existing experimental results, the proposed theoretical model accurately captured the behaviour of SSTT-confined HSC columns. It is also concluded that the previously proposed stress–strain empirical model is reasonably accurate for SSTT-confined HSC columns of both circular and rectangular cross-section.