Optimization of longitudinal web stiffener location in horizontally curved plate girders

Plate girders used in bridges are usually deep beams with relatively thin webs and, subsequently, web buckling becomes an important factor to consider during their design. When the limit state of web buckling governs the design, transverse and longitudinal stiffeners may be used to increase section strength. Straight girders have been extensively studied with respect to stiffener placement, resulting in well defined recommendations for the most effective location of both transverse and longitudinal stiffeners. Horizontally curved girders have not been as extensively studied, especially when longitudinal stiffeners are considered, and their behavior is more complex.;This study explores simple span, horizontally curved, plate girders with yield stresses of 50 ksi (345 MPA) and investigates optimal horizontal stiffener location. Parametric studies are conducted for a range of girder radii, section slenderness and unbraced lengths using ABAQUS, and sections are examined under high moment-low shear, high shear-low moment and high moment-high shear conditions. Recommendations are proposed for the location of longitudinal stiffener in these three load cases, D/5 for the first case, D/2 for the second and D/4 or D/3 for the third one. Results are then compared to the nominal strength of cross-sections for all load cases. The study shows that in high moment-low shear and high moment-high shear cases girder curvature increases web stability, and there is no need for longitudinal stiffener to reach the nominal cross-section strength. However in high shear-low moment conditions, longitudinal stiffeners can be used to increase girder strength to resist shear.