Lateral-Torsional Buckling Capacity of Beams: An Analytical Formula for Beams with Patch Corrosion

A formula for elastic critical buckling moment is derived based on energy method for beams with change in cross section. The concept is based on that strain energy stored in a member during lateral torsional buckling is equal to the total work done by the external load of the beam. The formula can be used to calculate the non-dimensional slenderness and hence, design lateral-torsional buckling moment capacities of the beams with change in cross section. The derived analytical formula was used to calculate buckling capacities of beams, which have been subjected to two different patch corrosion scenarios. The capacities were also calculated for 12 different lengths for each corrosive scenario of the beam. The lateral torsional buckling moment capacities were also calculated by non-linear FE analysis and results are compared to verify the proposed analytical formula. The comparison shows that there is a good agreement between the capacities, and it verifies the accuracy of the derived formula.