Prediction of the elastoplastic in-plane buckling of parabolic steel arch bridges

Abstract

In this paper, a modified eigen-buckling algorithm based on eigenvalue analysis was presented for evaluating the in-plane buckling strength of parabolic steel arch bridges. The buckling strength of parabolic arches under uniformly distributed vertical loads was studied. The slenderness parameter was modified to unify the buckling curves. Parametric analysis was carried out to study the applicability of the new algorithm. Finally, a case study regarding the bearing capacity of a steel arch bridge was performed to verify the proposed method. The results showed that the influences of geometric imperfections, rise-to-span ratio, and material yield strength of parabolic arches were taken into account by modifying the slenderness parameter. The buckling strength results of the arches using the modified dimensionless slenderness agreed very well with the straight column buckling curves in the specifications. The modified eigen-buckling algorithm provided very high accuracy in buckling strength assessment for parabolic steel arch bridges when the span was less than 200 m. The modified eigen-buckling algorithm predicted the load-bearing capacities of the arch bridge very well. Hence, the proposed method can be used for preliminary buckling strength evaluations in the bridge design stage.