Performance of New Sandwich Tube under Axial Loading: Analysis

A new composite tube consisting of two concentric steel tubes with polymer concrete sandwiched in between them was studied for its behavior under axial compressive loading. Twenty-six small-scale models of short composite tubes were tested and the findings were reported in a companion paper. Test results showed that the new composite tubes generally had a compressive strength 10–30% higher than the sum of the individual components. The ductility of the composite tube was much improved. In this paper, an analytical model is presented to predict the response of the sandwich tube under an axial load up to its peak strength. The tracing of the load-deformation curve was accomplished through an iterative procedure. An empirical formula for the peak strength of the sandwich tube is also presented. Both the analytical model and the empirical formula predict the peak strength of the sandwich tube well.