Numerical Analysis and Bearing Capacity Calculation of Steel‐Reinforced Recycled Aggregate Concrete‐Filled Square Steel Tube Columns Under Low Cyclic Loading

ABSTRACT On the basis of experimental investigation, this study conducted the finite element nonlinear analysis on the hysteretic performance of steel‐reinforced recycled concrete‐filled square steel tube columns under low cyclic loading using ABAQUS software. Specifically, the numerical model of columns takes into account the mechanical characteristics of recycled concrete and the constraint effect of the square steel tube. The stress nephogram and deformation failure characteristics of columns were analyzed, and the load–displacement hysteresis curves as well as the skeleton curves of columns were also obtained. By comparing the numerical calculation results with the test results, the rationality and effectiveness of the numerical model of columns were verified, and further parameter analysis was also carried out in detail. The results indicate that the profile steel and square steel tube at the column base yielded successively, while the recycled concrete inside the column was crushed simultaneously, exhibiting a distinct plastic hinge failure mode. Within the analyzed parameter range, increasing the strength of square steel tube significantly enhanced the column's bearing capacity but slightly reduced its ductility. Enhancing the wall thickness of square steel tube substantially improved the column's bearing capacity and deformability. Reasonable design of the shear span ratio of the column is very important for its seismic performance, so the columns will be subjected to the bending ductility failure as much as possible in the actual project. In addition, with the increasing replacement percentages of recycled coarse aggregate, the bearing carrying capacity of the column increases less, and its ductility decreases slightly with the increasing replacement percentages. Based on the above research, the calculation methods are proposed to evaluate the horizontal bearing capacity of steel‐reinforced recycled concrete‐filled square steel tube columns.