Study On The Mechanical Behavior Of Portal Frame Structure With The Steel Skeleton Light Roof Panel

For the portal frame factory used the lightweight slab with frame,the roof dead load is usually 1.5 kN/m2,which is greater than 0.5 kN/m2 of the traditional portal frame factory used the profiled steel sheet.When designing the factory by the Code for Design of Steel Structures,the design section of rigid-frame beam and column is usually too large.And it is mostly determined by the structural requirements of the global and local stability,rather than the strength.The construction cost will increase substantially,which is uneconomical and unreasonable.Simultaneously,the gravity second order effects of the rigid frame will be more obvious,the sidesway of column top and the additional internal force of component will increase,because of the larger mass source of the lightweight slab with frame.It will also enlarge the horizontal load of the rigid frame under seismic condition,influenceing the seismic performance of rigid frame.In this paper,four portal frames are experimentally studied,and then the corresponding finite element model is established and loaded.The correctness of the finite element model is verified by compared the finite element analysis results with the experimental results.Then the parametric analysis of the portal frame is carried out.Finally,for the I-shaped axial compression members and bending members,the plate width and width ratio limit formula in the Code for Design of Steel Structures is relaxed by introduceing the reduction factor.And a new limit formula is derived.This paper mainly completes the following work:(1)Four portal frames are experimentally studied.Four rigid frames are divided into two groups,the first group is carried out the loading test under the action of vertical force alone and the second group is carried out the loading test under the combined action of vertical force and horizontal force,observeing and recording the damage process and characteristics of each frame.The mechanical characteristics and ultimate bearing capacity of the portal frame under the action of the vertical force and the vertical force and the horizontal force are obtained by the analysis of structural displacement data and strain data.(2)The finite element model is established and loaded by finite element software based on the loading test of the frame.The correctness of the finite element model is verified by compared the finite element analysis results with the experimental results.(3)The buckling analysis of the vertical load and the vertical load and the wind load are carried out by finite element software.By changing the parameters such as the ratio of the high span ratio of the frame,the width ratio of the beam and column,the thickness ratio of the beam and column,the vertical load and so on,the influence of them on the mechanical properties of the frame is analyzed.(4)The formula of the width and thickness ratio of the plate and the bending plate in the Code for Design of Steel Structures is analyzed in detail.On this basis,the reduction factor is introduced for the deficiency of the normative formula.The formula of the width and width ratio of the I-shaped plate is deduced from the actual maximum working stress of the component,compareing with the normative formula,and for the engineering and technical personnel to provide design reference?...