Evaluation on story-based stability in multistory frame under various restraining conditions

Abstract

To estimate the critical buckling load, the effective length approach isolates a critical column inside a frame and analyses the rotational and translational stiffness of its end restraints. Although designers proportion leaning columns with K = 1, which is the correct K-value based on the column failure mode, buckling analysis fails to predict these values due to the influence of nearby columns and beams. In current design practise, beam-to-column and column-base connections in steel frames are typically idealised as wholly pinned or totally stiff connections. Various studies have demonstrated, however, that the semi-rigid behaviour of the systems beam-column connections affects the internal efforts in the structural parts, therefore the buckling critical loads and corresponding effective lengths of the compressed elements were also taken into account. In this study, a numerical analysis of the Effective length of column in multi-storey frames with single bay and dual storey (G + 2) is tried with variation in storey heights using rigid and semi-rigid jointed frames with rigid and semi-rigid jointed frames is undertaken. Webber's empirical equations are efficient in rigid frame systems for calculating the effects of adjoining columns and their critical buckling loading of the isolated column. The effective length K factor with the variance in critical length with different storey heights acquired a greater value when compared to other models. Moment rotations in semi-rigid jointed frames were influenced by differences in fixity factors in semi-rigid frames. The rigidity coefficient dropped as the stiffness coefficient increased, leading in an increase in the effective length factor.