| Title |
A Study on evaluation of the elasto-plastic buckling load for an overall steel frame in unbraced frame systems |
| Abstract |
The frame stability has to be discussed on the basic parameters such as the strength of an overall frame, deterioration of frame stiffness, and load conditions. Thus, it is necessary to be evaluated and treated as an overall frame stability problem in stead of regarding as the buckling problem for a single column. But the estimation method for buckling load of frame described in the current construction codes(Korea, Japan) are usually based on the concept that the buckling load is obtained from unlimited uniform frame without considering the conditions in an individual frame. Therefore, when discuss on the buckling load coefficient (called k-factor) of non-uniform frame with the different axial load distributions, the k-factor have to be evaluated from the buckling analysis of the overall frame. And the analysis of the overall frame is necessary to be considered on the limitations of axial forces and the slenderness ratios of steel columns in frames. Because of the above mentioned reasons, the current k-factor charts are reexamined in comparision with the elasto-plastic buckling load of the overall frame obtained from several numerical analysis results.This paper describes the elasto-plastic analysis techniques considering instability of frame due to the sidesway,the buckling length coefficient(k-factor) of a column in the frame with various load distribution, and discussion on the limitations of axial forces and slendeness ratios of columns with considering the analysis results, and try to present new k-factor design aide charts for the 3-story 2-bay plane frame. |