Elastic lateral torsional buckling of unbraced and braced planar frames

Abstract

A general finite element formulation to obtain lateral-torsional buckling solution of braced and unbraced planar structures loaded in-plane, is presented. The effects of in-plane deformations on lateral-torsional buckling are included. In-plane deformations are determined by following the loading path in incremental steps, through a series of equilibrium states and the critical load is found by determining the point at which the determinant of stiffness matrix of out-of-plane deformations becomes zero. The validity of the formulation is verified by testing for convergence and comparing the solutions with available results. The behaviour of unbraced and braced frames are investigated using this formulation.