Comparative analysis on failure mode and fatigue life prediction of U-rib-to-deck welded joints: Unraveling design-critical factors in orthotropic steel decks

In this study, a comparative analysis of failure modes and fatigue life prediction with experiment correlation is conducted using hot-spot stress extrapolation, notch effect modeling, and traction structural stress extraction. The variable amplitude multiaxial fatigue effect is considered in the combined structural stress factor. Critical gaps in understanding how stress representations affect fatigue life predictions are addressed by applying these approaches to two distinct joint configurations. The stress distribution at failure-prone locations associated with dominant fatigue failure modes is characterized by three common stress analysis methods. A key achievement lies in the application of stress analysis techniques to uncover design-critical parameters that have previously been overlooked in orthotropic steel decks. A comprehensive exploration of the adequacy of fatigue test design is presented examining: (i) the mechanical significance of notch radius selection in stress gradient characterization; (ii) directional fatigue strength responses under realistic vehicular loading; and (iii) boundary condition effects of adjacent U-rib components on stress states.