Stress behaviors of rib-to-deck double-sided weld detail on orthotropic steel deck

Abstract

To clarify the stress behaviors at a rib-to-deck (RD) double-sided weld detail, controlled truck loading tests were first performed on a newly built long-span cable-stayed bridge with orthotropic steel decks (OSDs). A specifically designed truck loading scheme were employed to simultaneously obtain stress records at the outside weld of the RD detail. A solid FEM panel model was established to determine the stress at the RD double-sided weld detail. It was found that the stress at the detail under wheel loads was dominated by significant local effects, where the apparent stress at the details was produced if their distances to the wheel center were not larger than the rib spacing in the bridge transverse direction or the floorbeam spacing in the bridge longitudinal direction. In addition, each axle could produce an individual stress cycle only when the detail was underneath the deck plate covered by the wheel load distribution width. The FEM results indicated that among the three typically transverse loading locations, the riding-rib-wall loading was the most critical, and generated the highest stress range at the RD double-sided weld detail. The stress range at the outside weld of the detail was higher than that of the inner weld, hence stress measurements outside the detail could conservatively be used for evaluating the fatigue of existing OSD bridges that use the RD double-sided weld detail. The results also provided strong support for the FEM analysis of the OSD using a panel model loaded with a one-sided twin axle.