Eccentric compression behavior of four-limb concrete-filled steel tubular latticed columns

This paper presents experimental and numerical investigations on eccentric compression behavior of four-limb concrete-filled steel tubular latticed columns. Eccentric compression tests were conducted on stub and slender latticed columns with varying eccentricities. The failure modes, load-shortening curves, and ultimate loads of the specimens were obtained through the tests. The experimental results indicate that the steel tubes of the column limbs yielded and the core concrete was crushed at the peak load. As expected, the ultimate load decreased as the eccentricity increased both in stub and slender specimens, with a more significant reduction observed in slender specimens. Subsequently, finite element analysis was carried out. The finite element models were established and validated based on the experimental specimens, followed by a parametric analysis to investigate the influence of slenderness ratio of the member, steel ratio, material strengths, and confinement coefficient of the limb, and cross-sectional area of lacing tubes on N-M curves of the four-limb concrete-filled steel tubular latticed columns. The design methods provided in the current design code for calculating the eccentric compression strength were evaluated based on a data pool from this research and existing experimental research. In order to improve the accuracy for determining the ultimate strength of the four-limb concrete-filled steel tubular latticed columns under combined compression-bending loads, a method was proposed and validated by the established database, with an average error of 3.8%.