Development of residual stress model of orthotropic steel decks using measurements

Orthotropic steel decks are widely used in the bridge engineering practice due to light weight, high performance and high ultimate strength-to-weight ratio. Purpose of the current paper is developing the first residual stress model for orthotropic steel decks (OSDs) with U-shaped stiffeners based on residual stress measurement results. The proposed simplified residual stress model is valid for OSDs with single-bevel butt welds, manufactured from steel grade up to S355. Distribution and magnitude of manufacturing-induced residual stresses due to hot rolling, thermal cutting, cold-forming, welding, etc. are determined using contour method with thin-plate smoothing spline. It makes it possible to interpret two-dimensional full-map residual stresses, instead of conventional pointwise residual stress measurement techniques, resulting in higher spatial resolution. Longitudinal residual stress patterns are evaluated in representative cross-sections clearly indicating high stress peaks near the welds, even exceeding yield strength of the base material, while the influence of thermal cutting and cold-forming can be addressed as well. Statistical evaluation of measurement results is carried out, which resulted in mean standard deviation of 22 MPa and 34 MPa in the stiffener and deck plate, respectively, which is comparable with the accuracy of other measurement techniques, e.g., X-ray diffraction method or hole-drilling technique.