Study on Axial Compression Behavior and Bearing Capacity of Concrete-Filled Steel Tube Columns with Iron Tailings Sand

The depletion of natural river sand resources in the construction industry and the pollution caused by iron tailings storage in the steel industry are the two major challenges currently faced. The use of iron tailings in construction materials is widely regarded as one of the most sustainable and cost-effective approaches. Based on C30 concrete, 12 steel tube iron tailings sand (IOT) concrete columns with different IOT substitution rates were designed and fabricated in this paper, and axial compression test research was conducted on them; finite element simulations were conducted for comparison with the experimental results, focusing on the influences of IOT substitution rate (0–100%), steel pipe wall thickness (1–4 mm), and steel strength (Q235, Q355, Q390, Q420, Q460) on the bearing capacity of concreted steel tube columns were parametrically analyzed. By comparing the calculation methods of the bearing capacity of concrete-filled steel tube columns in five relevant standards, the calculation formula for the bearing capacity of IOT columns was corrected and obtained. The results show that the failure mode of the IOT column is similar to that of the ordinary column, and the steel tube wall has all undergone circumferential band shear buckling. As the replacement ratio of IOT increases, the load-bearing capacity of columns initially improves and then declines. The finite element analysis results show that the bearing capacity of the IOT column is directly proportional to the wall thickness of the steel pipe, and increasing the wall thickness of the steel pipe can effectively improve the bearing capacity of IOT columns. The discrepancy between the predicted and experimental bearing capacities of IOT columns obtained based on the revision of the “Technical Code for Concrete-filled Steel Tube Structures” (GB 50936-2014) is within 10%, which can effectively predict the load-bearing capacity of IOT columns within a certain range.