Research On The Mechanical Behavior Of Wall’s Inter-story With Cold-formed Steel Composite Structures Of "Frame-wall"

Based on the new composite structural system of "ring beams + frame columns + coldformed steel walls",which improved and proposed by the group earlier,cold-formed steel composite structures of "frame-wall" with wall was first proposed in this paper.The mechanical behavior of wall’s inter-story with cold-formed steel composite structures of "frame-wall" was studied from both experimental and numerical aspects,and the calculation model of lateral stiffness and shear capacity of two-story wall under horizontal load was established.First,four-scale specimens of different floors and end columns were tested under pseudostatic method.According to the performance indexes such as failure mode,hysteretic curves,skeleton curves and ductility,based on the experimental study of single-story wall,the mechanical performance of inter-story was investigated.Experimental results show that the mode of the cold-formed steel composite structures of "frame-wall" was mainly the failure of the link between the panel and the cold-formed steel;The use of square steel section can avoid the compressive buckling of the end column and improve the ductility and deformation performance of the wall,although it has little effect on the lateral stiffness and shear capacity of the specimen;the two-story specimens is no obvious drift and pull-out phenomenon of interstory bolts.According to the displacement meter measurement,the inter-story displacement tends to 0;Compared with the single-story specimen after taking into account the connection of inter-story the ductility and shear capacity of the two-story specimen decreased less than10%.Indicating that the force transfer of inter-story and the integrality of the walls performs well.Secondly,on the basis of experimental research,a numerical analysis model of two-story with cold-formed steel composite structures of "frame-wall" is established by using ABAQUS finite element analysis software,and the experimental results and the numerical simulating results were compared to validate to proposed FEA models.Then the influence of the interstory edge beams,the spacing of inter-story bolt,and the thickness of the square steel section,the aspect ratio on the wall to a certain extent.The shear capacity and the lateral stiffness influenced slightly of the wall’s inter-story edge beams and the spacing of the inter-story bolt with the decrease of the aspect ratio of the specimens,the lateral stiffness and shear capacity of the specimens are greatly improved.Finally,the analysis model of lateral stiffness and shear capacity of two-story with coldformed steel composite structures of "frame-wall" was proposed.The calculation formula of lateral stiffness and shear capacity of two-story with cold-formed steel composite structures of "frame-wall" was derived,and its correctness was verified.The results show that: The calculation results of the formulas for lateral stiffness and shear capacity proposed in this paper based on superposition method are in good agreement with the experimental and finite element results,and the errors are about 15%,which can provide reference for the subsequent calculation of the lateral stiffness and shear capacity of similar walls.