Buckling and Shear Capacity of Horizontally Curved Steel Plate Girders

Horizontal curvature offers many benefits related to the design and construction of bridges and is often used for bridge designs in complex road geometries. Though horizontal curvature provides geometric and alignment benefits from a roadway design perspective, curvature introduces torsion and warping that complicates bridge behavior. This is especially true for steel, plate girder bridges that are torsionally weak and contain slender cross-sectional elements. While the impact of horizontal curvature on flexural response of steel girders has been studied, the impact of horizontal curvature on plate girder shear strength has not been thoroughly evaluated. While a number of studies have looked at the shear strength of slender, straight, plate girder webs, limited studies have examined shear strength of horizontally curved plate girders with slender webs. Jung and White experimentally investigated horizontal curvature influence on shear strength. Batdorf computationally investigated how horizontal curvature impacts slender, steel web panels via derivation of a shear buckling coefficient that included horizontal curvature. This study investigated how horizontal curvature influences steel, plate girder, shear strength. Shear behavior was examined computationally using calibrated Finite Element Models (FEM) to perform parametric studies that incorporated horizontal curvature and critical geometric properties. This information was used to develop two shear buckling coefficients, one based on simplified representation of Batdorf’s shear buckling coefficient and the other by introducing horizontal curvature into Timoshenko and Gere’s shear buckling coefficient. Effectiveness of these shear buckling coefficients was assessed via comparisons between shear capacities from the American Association of State Highway and Transportation Officials Load and Resistance Factor Design Bridge Design Specifications (AASHTO LRFD). Comparisons involved girder FEM models whose properties cover the range of possible horizontal curvatures, web slenderness and panel aspect ratios. After assessing how horizontal curvature could influence shear behavior, possible beneficial effects were assessed by evaluating increased possible increases in shear stiffener spacing using proposed shear buckling coefficients. Results showed that horizontal curvature enhanced shear strength for the slender, steel girder webs that were studied. Including curvature during web design could also increase maximum allowable shear stiffener spacing