SENSITIVITY ANALYSIS OF CRITICAL TORSIONAL BUCKLING LOAD OF THIN-WALLED I-COLUMNS RESTING ON ELASTIC-FOUNDATION

The sensitivity analysis of the critical load of torsional buckling of thin-walled I-columns resting on a Winkler-type elastic foundation is presented. The column behaviour is described according to the theory of a thin-walled beam with non-deformable cross-section. The first-order variation of the critical load due to the design variable variations is derived. The cross-section dimensions, except for the web height the column material constants and the foundation stiffness, are assumed to be the design variables. The single eigenvalues are only discussed. Finally, a numerical example dealing with a simply supported I-column is presented. The accuracy of the approximation of the critical load change, caused by the design variable variations by means of its first-order variation, is also investigated.