Parameter priority of circular concrete-filled double-skin tubular slender beam-columns under eccentric loading

This study aimed to determine the parameter priority for the design optimization of circular concrete-filled double skin tubular (CFDST) slender beam-columns under eccentric loading. Experimental investigations were conducted on four geometrically distinct CFDST beam-columns subjected to eccentric loading to analyze their behavioral responses. A finite element (FE) model was developed and calibrated using the experimental data. The FE simulations were performed on seven parameters, including load eccentricity, concrete strength, steel strength, outer tube thickness, inner tube thickness, lateral curvature, and end fixity to determine their respective impacts. By varying each parameter by 10%, the ultimate capacity of the columns was affected by different percentages. The load eccentricity was found to have the highest contribution of 58.7%, followed by fixity (16.0%), steel strength (9.3%), outer tube thickness (8.8%), inner tube thickness (3.5%), concrete strength (2.5%), and lateral curvature (1.2%). These findings establish the priority of the parameters, highlighting the significance of load eccentricity in the optimization of circular CFDST slender beam-columns under eccentric loading.