Flexure–shear interaction influence on curved, plate girder web longitudinal stiffener placement

Recent studies (Issa-El-Khoury, 2010; Issa-El-Khoury et al., 2015), demonstrated the beneficial influence that horizontal curvature could have with respect to longitudinal stiffener requirements for thin webs in bridge plate girders when those webs are subjected to pure bending. These studies showed that, when longitudinal stiffeners are required in a slender web, curvature did not drastically alter optimal stiffener placement requirements from what is currently recommended for similarly proportioned straight webs (American Association of State Highway and Transportation Officials (AASHTO), 2007), and, more importantly, there were certain instances where curvature enhanced web stability to eliminate the need for longitudinal stiffeners. However, it is recognized that, in most cases, curved plate girder webs are not subjected to either pure bending or pure shear but a combination of the two. Therefore, an extension of previously published findings to examine the response of curved, plate girder webs under a combination of bending and shear was necessary to validate or refute the pure bending findings. Those studies are summarized herein and they demonstrated that, for the ranges of parameters that were examined and when acted on by bending and shear, placing longitudinal stiffeners either D/3 or D/4 below the top flange, with D being the web depth, were optimal identified positions and that, at lower radii and in similar fashion to previously reported findings in pure bending, benefit realized from placing longitudinal stiffeners was offset by the effects of web curvature. •Extended previous study showing horizontal curvature influence on longitudinal stiffener requirements for webs in bending.•Examined influence of horizontal curvature on longitudinal stiffener needs, placement under combined bending and shear.•Optimal longitudinal stiffener positions D/3 or D/4 below top flange.•Benefit realized from placing longitudinal stiffeners offset by web horizontal curvature for lower radii girders.