Testing and analysis on out-of-plane buckling behavior of concrete-filled steel tubular arch

Long-span concrete-filled steel tubular (CFST) arches have gained widespread use due to their high strength, excellent seismic resistance, and ease of construction. However, long-span CFST arches are susceptible to out-ofplane buckling problem. In addition, experimental studies on out-of-plane buckling behavior of CFST arches remains limited. In that perspective, this study investigates the buckling behavior of a 9-m span CFST parabolic fixed arch. The arch has a circular cross-section and was subjected to uniformly distributed tilting loads. The effects of the residual stress on the buckling behavior of the composite arches were examined by building finite element models with solid elements. The influence of the confinement effects on the buckling response of the arches was then examined using models with simplified beam elements. It was found that the residual stress had limited effect on the buckling behavior of the arches. The confinement effect had insignificant influence on the buckling behavior of the arches with large slenderness ratios subjected to distributed tilting loads, while it became substantial for arches with low slenderness ratios. The model's accuracy was validated against the experimental data, and the comparative results demonstrated its capability to reliably predict the buckling behavior of CFST arches.