EVALUATION METHOD FOR EFFECTIVE LENGTH FACTOR OF NON-SWAY BUCKLING FOCUSING ON ROTATIONAL STIFFNESS AT FRAME JOINT NODE

This study proposes the RS (Rotational Stiffness) method as a general approach for evaluating the effective length factor for frames that buckle without nodal displacement, focusing on the rotational stiffness of frame joint nodes. The RS method enables calculation of the effective length factor through buckling analysis of a reduced model that consists of the peripheral members connected to the node dominant in the frame buckling behavior (Buckling Associated Node, BAN). The effective length factor obtained by the RS method can be either larger or smaller than the actual values, with estimation errors ranging from approximately -1.5% to 2.5%.