Study on Eccentric Compression Mechanical Characteristics of Basalt Fiber-Reinforced Recycled Aggregate Concrete-Filled Circular Steel Tubular Column

During this study, eight basalt fiber-reinforced recycled aggregate concrete-filled circular steel-tubular (C-BFRRACFST) column specimens were subjected to eccentric compression tests with different replacement ratios of recycled coarse aggregate (RCA), basalt fiber (BF) contents, length-diameter (L/D), and eccentricity. The whole process of stress as well as failure mode of the specimens were observed, and a load–displacement curve as well as a load–strain curve for the specimens were measured. The impacts of various parameters upon the bearing capacity, peak displacement, and ductility coefficient of the specimens were analyzed. Subsequently, a 3D finite element model of the C-BFRRACFST column was established, and the whole process of stress was simulated. Based on the finite element simulation results, the N/Nu-M/Mu correlation strength curve of the C-BFRRACFST columns was verified. The exploration demonstrated that under eccentric load, the C-BFRRACFST column eventually underwent destruction of the overall instability. The load–axial displacement curve was characterized as three stress stages: elastic, elastic–plastic, declining, as well as declining stages. The strain of the mid-span section for the specimens follows the plane section assumption, and the lateral deflection basically follows the sine waveform curve. The ultimate bearing capacity of the specimens exhibited little change as the replacement ratio of RCA improved, while the ductility progressively reduced. Furthermore, the ultimate bearing capacity of the specimens failed to be obviously changed as the BF content enhanced, while the ductility progressively rose. Increasing the L/D gradually reduced the specimen’s ultimate bearing capacity alongside its ductility. The corrected N/Nu-M/Mu curve agreed well with the findings of finite element simulation.