The Practical Method To Determine Column Effective Length

Abstract:Calculation of effective length of columns is key of stability checking in design, therefore some formulas and tables are given in Code for Design of Steel Structures (GB50017-2010), which show some application Limitations. Firstly it is used of approximate treatment, so the result of the effective length of columns is conservative, such as the framework attached the swinging columns; secondly these formulas and tables are made based on assumptions for regular frames. For some special cases, such as existence of the large difference of the column axial force or column length among the framework columns, these formulas and tables are no longer applicable. Last it is difficult to find out the trends of effective length cause by the related parameters. The practical calculation charts and approximate calculating formulas are derived by authors by using the displacement method with the second-order theory and equilibrium method.Firstly in this paper the characteristic equations of the columns and the practical calculation charts are derived with the displacement method with the second-order theory and equilibrium method and equilibrium method. It is quick to determine column effective length and find the intuitive trends of the lengths.Secondly the approximate calculating formulas are derived with the deflection method and cmpare the approximate results with the accurate results which is caculated by the displacement method with the second-order theory and equilibrium method to find the factors which influence the calculation precision.Last ccmpare the results which are caculated by ANSYS with theoretical calculated results to identify the correctness of the theoretical calculated results.