Out-of-Plane Inelastic Buckling and Strength of Steel Arches

Abstract

An arch loaded in-plane may suddenly deflect laterally and twist out of the plane of loading and fail in a flexural-torsional buckling mode. This paper investigates the out-of-plane inelastic flexural-torsional buckling and strength of steel arches using a finite-element model in a three-dimensional nonlinear inelastic analysis. The 3D elastic-plastic behavior of an arch is determined by taking into account the effects of the in-plane curvature of the arch, subtended angle, large deformations, material inelasticity, initial crookedness, and residual stresses. The strengths of steel arches in uniform compression and in uniform bending are studied. It is found that the design rules for steel columns and beams cannot be used directly for the design of steel arches. Design rules for steel arches in uniform compression and in uniform bending are developed based on the results of the finite-element analyses. The effects of initial crookedness and twist, residual stresses, and yield stress on the strengths of arches are also investigated.