OUT-OF-PLANE INELASTIC BUCKLING AND STRENGTH OF STEEL ARCHES

An arch loaded in-plane may suddenly deflect laterally and twist out o f 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-plas tic behavior of an arch is determined by taking into account the effec ts of the inplane curvature of the arch, subtended angle, large deform ations, material inelasticity, initial crookedness, and residual stres ses. The strengths of steel arches in uniform compression and in unifo rm bending are studied. It is found that the design rules for steel co lumns 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 analy ses. The effects of initial crookedness and twist, residual stresses, and yield stress on the strengths of arches are also investigated.