ABSTRACT
Thin-walled structural members are commonly subjected to torsion that produces significant distortion of the cross section. One common structural scenario in which the prediction of distortion-induced stresses is important is the use of thin-web plate girders in curved bridges. The development of appropriate design criteria for the design of curved plate girders depends on an understanding of the stability behavior of the curved web and the prediction of distortion-induced stresses. The simple presence of curvature in curved plate girders greatly complicates behavior and design over that of straight girders. Bifurcation buckling of the web will not occur if there is significant curvature. Curvature induces both warping and distortion of the cross-section. Curvature also results in a nonlinear distribution of membrane stresses through the web depth, which causes an increase in normal stress in the flanges. This is additionally complicated by significant geometric nonlinear behavior. The purpose of the investigation in which this paper is based was to evaluate the finite displacement behavior I-shaped plate girder web panels and to formulate strength reduction equations that represent the effects of curvature. This paper presents the development of a theoretically pure analytical model, a review and comparison of equations developed by others, a description of nonlinear characteristics of the curved web subjected to bending, and a proposal for design.
