This paper presents a numerical method for predicting the influence of local buckling in component plates and distortional phenomenon on the ultimate strength of thinwalled, welded steel box girders curved in plan. Based on the analytical results of cylindrical steel shell panels under compression and bending, a modified stress-strain curve allowing for local buckling of plate components is proposed. The effect of distortion is considered through incorporating additional strain in the reference stage of the incremental process in the nonlinear flexure analysis. Theoretical predictions obtained using the proposed method are compared to experimental test results. Nonlinear behavior of the test girders are illustrated and reasonable agreement between tests and theory is observed.
