Study On Theproperties Of The Light-gauge Steel Truss Beam With Z Shaped Clips And Composite Floor

Nest light-guage steel truss is made up by butterfly-like clisps acting as the web memble and two hollow rectangular tubes acting chord member which were connected with clips by self-tapping screws. According to the project cases,the truss has a low stiffness during the normal maintenance.Based on it,the Z shaped clip is proposed to instead of butterfly-like clip.The composite floor are made up by truss and OSB plate,which is not considered in to mechanical calculation.In order to get a accurate understanding,it is necessary to study the mechanical behavior of composite floor.The static loading experiments of light-guage steel truss with Z shaped clips and composite floor composited by light-guage steel truss with Z shaped clips and OSB slab are carried out for the above problems. The results of these experiments show that the ultimate load of truss with Zshaped clips and the truss with butter-like clips are close,But the stiffness of truss with Zshaped clips is higer about 20%-50% than the truss with butterfly-like clips. The steel consumption of truss with Z shaped clips is lower than the truss with butterfly-like clips when having the the same ultimate load;The OSB slab of composite floor effectively prevents the plastic deformation of top chord in midspan when subjected the load and makes the top chord get into yield steadily At last,the composite floor loses the load capacity with buckling marked by the whole section of top chord getting into large plastic deformation.The ultimate load of composite floor is higher about 20% than the single truss with Z shaped clips.The ultimate load capacity of composite floor in the normal maintenance is about 5% higher than the single truss.The optimization analysis of truss with Z shaped clips is completed,getting the load capacity influences caused by the span-depth ratio,section height,section thickness,clip number and clip distance.The nonlinear finite element analysis of the composite floor is completed by ABAQUS.In order to get more accurate model,the normal contact,tangential friction and slip between OSB slab and top chord are considered in the model.The model is compared with specimens to vertify the accuracy of model.Then the model is used to do parameter analysis for the properties of composite floor.The analysis shows that the thickness of OSB slab can improve not only the ultimate load capacity but also the elastic and plastic stiffness of composite floor;The space between the srews, especially the space in the midspan can affect the load capacity too,which can improve the plastic stiffness but not the elastic stiffness.Lastly, design formula of light-guage steel composite floor and a simplified model for designing the load capacity in normal maintenance are suggested in this paper.