Finite element analysis of curved steel girders with tubular flanges

A tubular flange girder is an I-shaped steel girder with either rectangular or round tubes as flanges. A tubular flange girder has a much larger torsional stiffness than a conventional I-shaped plate girder and less potential for cross section distortion than a box-girder, and is, therefore, an interesting alternative girder for horizontally curved steel bridges. Finite element (FE) models of curved tubular flange girders are presented in this paper, considering material inelasticity, second-order effects, initial geometric imperfections, and residual stresses. A parametric study is performed using the FE models to study the effects of stiffeners, tube diaphragms, geometric imperfections, residual stresses, and cross section dimensions on the load capacity of curved tubular flange girders. Finally, the FE results for curved tubular flange girders are compared with results for corresponding curved I-shaped plate girders, and the advantages of tubular flange girders are summarized.