A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering of the Asian Institute of Technology, Bangkok, Thailand

Thesis (M.Eng.) - Asian Institute of Technology, 1977

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. A main feature is that the in-plane and out-of-plane deformations are treated separately to reduce computational efforts, unlike most of other formulations dealing with a similar subject. 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 un braced and braced frames are investigated using this formulation.