Research On Mechanical Performance Of Cold-Formed Steel Framing System Of Low-Rise Residential Buildings

In recent years,the cold-formed thin-wall steel framing system has been used in developed countries,for example,USA,Australia, Japan et al.Because of the fast speed of construction, good performance of earthquake and wind resistance, higher mechanical degree, it has been used more and more widely in china. After Wenchuan earthquake,in the reconstruction of disaster area, the cold-formed thin-wall steel framing system is used in a large proportion of the buildings.Now the tests and studies of cold-formed thin-wall steel framing system of low-rise residential buildings were mostly focused on members.There are seldom researches reported on structural framing systems.The mechanical property of low-rise residential buildings depends not only on the performance of cold-formed members and composite walls, but also on construction and many other factors, such as the mode of disposal of walls,form of openings on floors and walls and so on.The main purpose of this paper is to give an all-round analysis of the response of the cold-formed thin-wall steel framing system of low-rise residential buildings and to check its mechanical property. The nonlinear finite element model was built using finite element analysis program Ansys.Also the static push-over analysis was adopted to analyze the mechanical property in these load case, such as dead load, live load, wind load and gravity load.Meanwhile, the elastic plastic relation was adopted to analyze the seismic bearing capacity of low-rise residential buildings.The main work is composed of the following three parts:(1)The finite element method (FEM) was developed to analyze the shear resistance of steel stud walls in cold-formed steel frame system of residential buildings.The wall sheathing and steel stud were simulated by plastic shell element (SHELL181)in the FEM model,respectively. The material and geometric nonlinearity were considered.The screws between the wall sheathing and frame were modeled through coupling methods.A detailed parametric study by the FEM is carried out with the material of wall panel,the strength of steel members,the stud spacing, the wall height, and the screw spacing to analyze the shear-carrying capacity of the walls.The conclusions will be reference for designer to choose the rational parameters.(2)The low-rise cold-formed entirety elastic model was built to analyze the structural internal force, deformation and regular changes under frequent earthquake.(3)Based on the mechanical property of cold-formed thin-wall steel structures, the entirety elastic-plastic model was established to compare the model of different structural system.Several factors are taken into consideration,such as whether having wall pane, whether having any strengthening in the hole,and different material of wall panel,and so on.