Behavior of steel reinforced UHPC-filled stainless steel tubular columns under eccentric loads

Abstract

This study was conducted to examine the behavior of steel-reinforced ultra-high performance concrete-filled stainless steel tubular (SRUHPCFSST) intermediate columns under eccentric loads. There were nine columns tested in the test program, all of which were subjected to static eccentric loading with consideration given to the effects of the eccentricity, diameter-to-thickness ratio, steel ratio, and eccentric direction. The columns were evaluated to determine their performance characteristics such as ductility, load-displacement relationships, load-strain relationships, and failure modes. The intermediate SRUHPCFSST columns demonstrated good load-carrying and deformation capacity as well as a clear instability failure under eccentric compression after reaching their maximum load. The ultimate bearing strength of the columns decreased significantly with the increase of the diameter-to-thickness ratio and eccentricity, and the increase of the steel ratio or loading in the major axis of the steel skeletons effectively improved the ultimate bearing strength and ductility of the columns. The numerical simulation of the eccentric compression on the SRUHPCFSST was carried out with the finite element software ABAQUS, and the effects of the L/D ratio, concrete strength, steel skeleton strength, and large eccentricities on its eccentric bearing strength were expanded and analyzed. The eccentric bearing strength of the SRUHPCFSST intermediate columns was calculated using a formula derived from the test data and the numerical analyses. The results of the equation correlated well with the experimental data and can serve as a reference for future research in this area.