Eccentric compression behavior of concrete-filled steel tubular stub columns with ultra-high-strength materials: Experimental and numerical study

Using ultra-high-strength materials in the concrete-filled steel tubular columns has potential to optimize cross-sectional dimensions and improve the performance and sustainability of offshore structures under the complex marine conditions. This study investigated the behavior and performance of ultra-high-strength concrete-filled square steel tubular (UHSCFST) stub columns when subjected to eccentric compressive loads using experimental tests and finite element analysis. Six UHSCFST column specimens were tested considering variations in material strength and eccentricity. The column response to the eccentric loads was analyzed, taking into account the failure mode, load-lateral deflection response, and longitudinal and transverse strains obtained from the tests. Additionally, finite element models of the tested UHSCFST columns were developed and validated by comparing the numerical and experimental results. Baseline simulations were conducted to extensively analyze the stress distributions of each component and identify the load-transfer mechanism during the loading process. The column models were also used to examine the effects of key parameters on the eccentric compression behaviors of the UHSCFST stub columns and determine the dominant parameters for developing design suggestions. These findings provide valuable information on the utilization of ultra-high-strength materials in CFST members for performance improvement. Furthermore, the results serve as references for the further design and evaluation of UHSCFST columns under different loading conditions.