Nicholas S. Trahair

Inelastic lateral buckling strength and design of steel arches

Arches resist general loading by a combination of axial compression and bending actions. Under these actions, an arch loaded in-plane may suddenly deflect laterally and twist out of the plane of loading and fail in a lateral buckling mode. This paper investigates the inelastic lateral buckling strength and design of steel arches under general loading using an advanced nonlinear inelastic finite element method of analysis. It is found that the subtended angle and load distribution significantly affect the lateral buckling strength of a steel arch. The effects of initial crookedness and twist and residual stresses on the strengths of arches are also important. The rules for designing steel beam-columns against inelastic lateral buckling cannot be used directly in the design of steel arches against inelastic lateral buckling under general loading because they do not include the effects of the subtended angle and the load distribution. The design rules developed in this paper provide conservative predictions for the lateral buckling strengths of steel arches under general loading, and offer considerable economies.