Out-of-Plane Strength Design of Fixed Steel I-Section Arches

The out-of-plane elastic and inelastic flexural-torsional buckling behavior and strength of fixed steel arches are studied in this paper using an advanced finite element model for the three-dimensional nonlinear analysis. The initial out-of-plane geometric imperfections, residual stresses due to manufacturing and curving, yielding, and inelastic flexural-torsional buckling are considered in the investigation. It is found that both the elastic and the inelastic flexural-torsional behavior of fixed arches are quite different from those of pin-ended arches. The strength design equations for pin-ended steel arches cannot be extended directly to fixed steel arches using the effective length method. Design equations for fixed steel arches subjected to uniform compression or to uniform bending, and an interaction equation for the strength check against out-of-plane failure for fixed steel I-section arches subjected to combined bending and axial compressive actions, are proposed.