Elastic Flexural-Torsional Buckling of Discretely Restrained Arches

Abstract

This paper presents a study of the effects of elastic discrete restraints on the elastic flexural-torsional buckling of arches in uniform bending and compression. It was found that established results for the elastic flexural-torsional buckling of restrained beams in uniform bending cannot be used directly for restrained arches in uniform bending, nor can those for elastic flexural or torsional buckling of restrained columns in uniform compression be used directly for restrained arches in uniform compression. Because of the curved profile of an arch, restraints are more effective in increasing the elastic buckling resistance of an arch than that of the corresponding straight member. Approximate formulas for the threshold values of the stiffness of the central torsional and lateral-translational restraints for a restrained arch in uniform bending and for the threshold value of stiffness of the lateral-translational restraints for a restrained arch in uniform compression at which the flexural-torsional buckling mode changes from being symmetric to antisymmetric are proposed. Approximate formulas for elastic flexural-torsional buckling resistance of centrally or end restrained arches in uniform bending and in uniform compression are also proposed. Finite element results show that these proposed formulas are accurate.