Numerical study on the seismic performance of phosphogypsum-filled cold-formed thin-walled steel composite walls

•A finite element model was developed to simulate the seismic performance of PFCFS walls.•Load-deformation curve, lateral stiffness, shear capacity, and ductility of the PFCFS walls with different design parameters were compared.•Formulas for predicting the lateral stiffness and shear capacity of PFCFS walls were modified. To conduct in-depth research on the seismic performance of phosphogypsum (PG) filled cold-formed thin-walled square steel tube (PFCFS) composite walls, a series of finite element analyses were conducted using the software ABAQUS. The study examined various factors, including PG strength, oriented strand board (OSB) configuration and thickness, stud strength and thickness, screw spacing, axial force ratio, wall sheathing coverage, and height-width ratio. After summarizing, the main findings are as follows: the lateral behavior of walls is significantly affected by PG strength and wall stud thickness, while wall sheathing configuration has a relatively low impact; increasing PG strength, wall stud thickness and strength, wall sheathing thickness, axial force ratio, and the number of wall sheathings (non vs. single vs. double sheathing), or decreasing self-tapping screw spacing and wall height-width ratio enhance the shear capacity of the wall; increasing PG strength, wall sheathing thickness, or reducing wall height-width ratio improve the lateral stiffness and ductility of the wall; increasing wall stud thickness and adding more wall sheathing can improve the lateral stiffness of the wall. However, this can reduce the wall's ductility; by decreasing self-tapping screw spacing or increasing axial force ratio, the lateral stiffness and ductility of the wall exhibit an increasing-then-decreasing trend; increasing wall stud strength does not significantly affect the lateral stiffness of the wall, but it does decrease the ductility. Finally, the simulated lateral stiffness and shear capacity of the wall were compared with the theoretical values, which showed good agreement.