Required Bending Rigidity for Transverse Stiffeners of Steel Plate Girders in Shear Loading: Numerical Investigation

Transverse stiffeners provide lateral support to slender webs along their span, enhancing the shear buckling resistance of steel plate girders. Moreover, intermediate transverse stiffeners are particularly crucial, because they anchor the forces generated by tension field action, mitigate out-of-web buckling, and support the edges of the web panel. The standard EN 1993-1-5 outlines three requirements for the design of intermediate transverse stiffeners: (1) strength verification, (2) a minimum elastic bending rigidity, and (3) a torsional rigidity check. However, research has demonstrated that applying the strength verification criterion often results in overly conservative designs due to assumed internal forces significantly exceeding those observed in numerical simulations and experimental studies. Consequently, US design standards have omitted this verification, focusing solely on the minimum bending rigidity requirement. A numerical study of 13,500 plate girders with diverse geometries and stiffener configurations was conducted to evaluate the minimum bending rigidity required for intermediate transverse stiffeners to ensure the ultimate shear resistance of steel plate girders. The analysis considered the effects of steel grade, web slenderness and aspect ratio, flange-to-web area ratio, and the presence of longitudinal stiffeners. The results indicate that the required minimum bending rigidity is particularly high for plate girders with slender webs, low aspect ratios, and high flange-to-web area ratios.