| Title |
Application of a Fictitious Axial Force Factor to Determine Elastic and Inelastic Effective Lengths for Column Members of Steel Frames |
| Keywords |
steel frame;effective length;fictitious axial force factor;system buckling analysis;inelastic stiffness reduction factor;강프레임;유효좌굴길이;가상축력계수;시스템좌굴해석;비탄성 강도감소계수 |
| Abstract |
In design of steel frames, it is generally believed that elastic system buckling analysis cannot predict real behaviors of structures, while inelastic system buckling analysis can give informative buckling behaviors of individual members considering inelastic material behavior. However, the use of Euler buckling equation with these system buckling analyses have the inherent problem that the methods evaluate unexpectedly large effective lengths of members having relatively small axial forces. This paper proposes a new method of obtaining elastic and inelastic effective lengths of all members in steel frames. Considering a fictitious axial force factor for each story of frames, the proposed method determines the effective lengths using the inelastic stiffness reduction factor and the iterative eigenvalue analysis. In order to verify the validity of the proposed method, the effective lengths of example frames by the proposed method were compared to those of previously established methods. As a result, the proposed method gives reasonable effective lengths of all members in steel frames. The effect of inelastic material behavior on the effective lengths of members was also discussed. |