Curling Z Section Steel Beam To Prevent Reinforcement Measures Of Distortional Buckling

In rencent years,the cold-formed steel has been widely used in industrial construction. With the application of the thin-walled members with edge stiffener,a new strength-governing mode, distortional buckling is emerged,it maybe become the dominating buckling mode when failure occured. distortional buckling of the thin-walled cold-formed structure was not mentioned explicit by GB50018-2002 specification.In this thesis, from the aspects of the suggested countermeasure, reinforcing measures can be valid to prevent the apperance of the distortional buckling.Firstly, five strengthening measures of adding diaphragms to restrain the occurrence of distortional buckling of the Z section beam with upright and inclined edges stiffeners are presented,and then FEM elastic and nonlinear analyses are conducted on strengthened lipped Z steel beam,comparisons are made between the validity of five strengthening measure.The best reinforcement measure is proposed based on the increase in the amount of steel.Next, FEM elastic and nonlinear analyses is carried out on the Z section beam with upright and inclined edges stiffeners under five strengthening measures of adding connecting rods, comparisons are made between five strengthening measure.Considering the amount of steel reinforcement parts and the rise of load-carrying capacity, comparisons are made between strengthening measure of adding diaphragms and adding connecting rods,the best reinforcement measures is proposed.Finally, using the finite element software analysis for different loads in the connecting rod and diaphragm reinforced with simple beam and continuous beam, found that for the simple beam, as long as the compression flange of beam was reinforced under strengthening measures of adding connecting rods and connecting rods, the suggested countermeasures can be valid to prevent the occurrence of distortional buckling; and for a continuous beam, the upper and lower flange of the beam must be reinforced to restrain the occurrence of distortional buckling. The reinforcement measures can not only prevent the occurrence of distortional buckling, but also increase the buckling load of beam. Through the economic index analysis, obtaining the best reinforcement measure under different circumstances, can be used as reference for future engineering applications.