Study On The Axial Compressive Performance And Shear Resistance Of Prefabricated Cold-formed Steel(CFS) Composite Walls Sprayed With Light Polymer Material(LPM)

In recent years,with the widespread promotion of green farm houses,cold-formed thin-walled steel-light polymer structure has emerged constantly in rural construction.This kind of structural system basically has a few types of components,fast construction speed and easy industrialization.Promoting the use of this type of structural system for the construction of green farm houses can effectively solve the problems of serious construction pollution,uneven construction quality and unreasonable building layout.As an important part of the structure,prefabricated cold-formed steel(CFS)composite walls sprayed with light polymer material(LPM)has in-depth study of its axial compression performance and shear resistance which have great significance to theoretical research and engineering applications.This paper developed experimental and finite element(FE)analysis on the axial compressive performance and shear resistance of prefabricated CFS composite walls sprayed with LPM.And the practical calculation formula of the axial compression bearing capacity of the composite wall panel is given.The specific research was summarized as follows:(1)Axial compression tests were carried out on 6 pieces of prefabricated CFS composite walls sprayed with LPM.According to the experimental results,the failure modes,load-displacement curve,load-strain curve,ultimate bearing capacity and so on were discussed.The results show that the failure characteristics of the non-faced composite walls are:distortion and buckling at the bottom of the column,and the bottom filler is crushed;the failure characteristics of the composite walls covered with cement fiberboard on both sides are:the cement fiberboard cracks and the self-tapping screw at the joint fails,the distortion of the column buckles,and the corners of the filler are crushed.The presence or absence of cement fiberboard on both sides and filler types have a great influence on the ultimate bearing capacity and rigidity of the composite walls under axial compression.The axial compression bearing capacity of the cement-based composite walls is significantly higher than that of the gypsum-based composite walls;the axial compression bearing capacity and stiffness of the composite walls covered with cement fiber board on both sides are much greater than the composite walls without panels.(2)The FE model of prefabricated CFS composite walls sprayed with LPM was established by ABAQUS software and verified well with the experimental results,then the parameters were analyzed.The results show that:(1)The type of panel,the thickness of the steel,and the loading method have a great influence on the axial compression stiffness and axial bearing capacity of the composite walls;(2)The type of panle has a greater influence on the axial compression stiffness and ultimate bearing capacity of the composite walls;(3)The axial compression bearing capacity of the composite walls under three-point loading is greater than that of the composite walls under concentrated loading;(4)The compressive strength of the filler has little effect on the axial compression stiffness of the composite walls,but it has a greater influence on the axial compression bearing capacity.(3)The shear performance test of 6 prefabricated CFS composite walls sprayed with LPM was carried out.And the change regulations of failure modes,load-displacement relationship curve,ultimate bearing capacity and elastic stiffness are analyzed.The results show that the failure characteristics of the composite walls without panel is that the filler is falling off,the bottom column is partially buckled,and the column is separated from the bottom track;the failure mode of the composite walls covered with cement fiber board on both sides is that the bottom of the cement fiber board is completely peeled from the keel,local buckling appears at the bottom of the column.The greater the stiffness of the filler,the greater the shear bearing capacity and elastic stiffness of the composite walls;cement fiber board on both sides greatly improves the shearing ultimate bearing capacity and elastic stiffness of the composite walls;the number of steel mesh layers has no obvious effect on the shear capacity and elastic stiffness of the composite walls.(4)By establishing a shear model of prefabricated CFS composite walls sprayed with LPM,it is found that the error of the FE results and the test results is small,and the simulated damage characteristics are in good agreement with the test phenomena.The results show that:(1)The maximum load and elastic stiffness of the composite walls covered with OSB panel are larger,while the maximum load and the elastic rigidity of the composite walls covered with PB panel are smaller;(2)The greater the thickness of the steel,the greater the maximum shear load and elastic stiffness of the composite walls;(3)The compressive strength of the filler has a greater influence on the bearing capacity of the composite walls,but has little effect on the elastic stiffness of the composite walls;(4)The magnitude of the vertical load value during loading has little effect on the shear capacity and stiffness of the composite walls.(5)The design calculation recommendations of the axial compression bearing capacity of prefabricated CFS composite walls sprayed with LPM are given.After trial calculation,it is found that the correlation coefficient between 0.0025 and 0.0027 can be reasonably obtained the ultimate bearing capacity of composite walls.