Experimental Study On Axial Compression Performance Of Cold-formed Thin-walled Square Steel Tube Skeleton Wall Filled With Phosphogypsu

With the gradual development of cold-formed thin-walled steel housing from low-rise to multi-story structures,the traditional cold-formed thin-walled steel composite walls can no longer meet the axial compression performance demands of multi-story cold-formed thin-walled steel housing.This paper proposes the use of phosphogypsum,an industrial solid waste,as a filling material for a cold-formed thinwalled square steel tube skeleton wall.Compared to traditional cold-formed thin-walled steel walls,phosphogypsum-filled cold-formed thin-walled square steel tube skeleton walls not only enhance the axial bearing capacity and overall stability of the wall but also improve its heat insulation,thermal insulation,and fire protection.In this paper,the axial compression performance of phosphogypsum-filled cold-formed thin-walled square steel tube skeleton walls is investigated through experimental studies,numerical simulations,and theoretical analysis.Additionally,relevant design methods are proposed.An experimental study was conducted to investigate the axial compression performance of eight fullsize phosphogypsum-filled cold-formed thin-walled square steel tube skeleton walls.The study aimed to examine the force characteristics and failure modes of the walls under vertical loads,analyze the axial compression capacity,load-displacement curve,load-strain curve,ductility coefficient,and axial compression stiffness of the specimens,and the influence of parameters such as phosphogypsum filling area,column thickness,phosphogypsum strength,and the presence or absence of wall panels on the axial compression performance of the specimens was investigated.The test results indicate that when the specimens were failure,the columns were crushed at the bottom end.Additionally,the phosphogypsum between the columns displayed diagonal cracks through the corners.The wall panels were primarily bulged and cracked outside the face.The self-tapping screws did not slip in relative misalignment,and the hole walls had slight extrusion deformation.Compared to the cavity wall,the infill wall exhibited significantly higher axial compression load capacity,stiffness,and ductility.Furthermore,the axial compression load capacity of the composite wall gradually increased with an increase in infill area,column thickness,and phosphogypsum strength.The phosphogypsum-filled cold-formed thin-walled square steel tube skeleton walls was numerically simulated using the finite element software ABAQUS.The correctness of the finite element model was verified by comparing the numerical simulation results with the experimental results.Based on this premise,the analysis was conducted to broaden the scope of influencing factors,including column thickness,steel type,phosphogypsum strength,friction coefficient,wall panel strength,wall panel thickness,and the presence of wall panels.The findings indicate that enhancing the load-bearing capacity of the wall can be achieved by increasing column thickness,utilizing high-strength steel,and increasing wall panel thickness.Notably,increasing column thickness can significantly enhance the axial compression stiffness of the wall while maintaining its ductility and deformation capacity.Based on the experimental study and finite element analysis,this study proposes formulae for calculating the axial compression load capacity of phosphogypsum-filled cold-formed thin-walled square steel tube skeleton walls.Additionally,this study introduces the cold-formed thin-walled steel column discount factor β,the inter-column phosphogypsum discount factor γ,and the intra-column phosphogypsum discount factor λ.The study considers the effects of different factors on the discount factor and uses a multiple linear regression formula for the calculation.Finally,the study compares the calculation results with the test results to verify the accuracy of the formula.