Stress Analysis of Rib-to-Deck Joints in Orthotropic Steel Deck Based on Nominal and Effective Notch Stress Approaches

This paper presents the stress analysis of the rib-to-deck (RD) joint in an orthotropic steel deck. Finite element models were developed to evaluate the effects of the wheel load location and weld penetration ratio on the nominal and effective notch stresses at the RD joint. The critical wheel load locations for fatigue-sensitive locations of the RD joint were investigated comprehensively. The potential locations of fatigue crack initiation were evaluated for weld penetration ratios ranging from 0% to 100% at different transverse locations of single- and double-wheel loads. The analytical results indicated that the critical location of fatigue crack initiation was influenced by the weld penetration ratio and transverse wheel load location. An increase in the weld penetration ratio decreased the root notch stress and significantly increased the potential for toe-deck cracking, as the wheel loads were applied at the RD joint and close to the adjacent rib. The nominal stress approach was used to identify the fatigue crack type accurately only for relatively high weld penetration ratios, with the wheel loads applied at the RD joint and over the rib. For the condition of 100% weld penetration ratio with the loads applied at the joint, the fatigue life corresponding to the effective notch stress approach ranged from 66% to 73% of the fatigue life obtained using the nominal stress approach.