Large-scale slender hybrid FRP-concrete-steel double skin tubular columns subjected to eccentric compression

Hybrid FRP-concrete-steel double skin tubular columns (hybrid DSTCs) are a new and promising form of columns that exhibits excellent structural performance and corrosion resistance. Previous studies on hybrid DSTCs have mainly been limited to small-scale specimens and paid limited attention to the behavior of eccentrically-loaded slender hybrid DSTCs. This paper presents the test results of two eccentrically-loaded large-scale hybrid DSTCs, including one short column and one slender column, of a larger test program aimed at investigating the behavior of large-scale slender hybrid DSTCs subjected to eccentric compression. A comparison of test results of the two columns reveals clearly the effect of slenderness on the load-carrying capacity and failure mode of eccentrically-loaded hybrid DSTCs. To capture the effect of slenderness on the behavior of eccentrically-loaded hybrid DSTCs, a theoretical column model, which traces the lateral deflection of columns using the numerical integration method and incorporates an eccentricity-dependent stress-strain model for concrete in hybrid DSTCs, was developed. It is shown that the column model is accurate in predicting the load-carrying capacity of hybrid DSTCs and reasonably accurate in predicting the lateral deflection of hybrid DSTCs.