Analysis of Lateral Buckling in Plane Frames

A general and systematic method of analyzing the elastic flexural-torsional buckling of rigid-jointed plane frames with I-section members and subjected to in-plane loads is developed. The in-plane equations are solved first, and these solutions are used to linearize the flexural-torsional differential equations. The buckling equations, which consist of the bending and torsion differential equations, and the boundary, compatibility, warping, and joint equilibrium equations are solved numerically by the method of finite integrals, and the critical load factor is obtained iteratively. A computer program is developed in which most of the equations are progressively eliminated. This leads to significant reductions in the storage requirements and the computing time.