EVALUATION OF EFFECTIVE LENGTH FACTORS FOR NON-UNIFORM FRAME USING STABILITY INDEX

In this study, the effective length factor was calculated using the SI method. Three analytical models were analyzed using the type of column bases, number of stories, number of spans, beam stiffness ratio, stiffness ratio reduction factor and story shear force distribution (Case I, Case II) as analytical parameters for a relatively even non-uniform frame, a frame with severely disturbed column stiffness and a frame with severely disturbed column axial forces, and the effective length factor obtained by the SI method was compared to the effective length factor obtained by the buckling slope-deflection method, and the validity of the SI method was investigated. The results showed that the SI method was able to evaluate the correct value of the effective length factor within an error of about 5% for both analytical models, regardless of the story shear force distribution.