Experimental Study on Fatigue Resistance of Rib-to-Deck Joint in Orthotropic Steel Bridge Deck

The stress state around a rib-to-deck (RD) joint in an orthotropic steel bridge deck is extremely sensitive to wheel-load location in the transverse direction. Fatigue cracks of various types can occur around the RD joint. In this study, a bending fatigue-test system was used to simulate an RD joint under the critical-load case. The fatigue tests for two groups of RD joint specimens with weld-penetration ratios of 15 and 75% were conducted to assess the influence of the penetration ratio on the fatigue-crack type and its fatigue resistance. Fatigue-test results suggest that the fatigue resistances of the RD joint specimens with 75 and 15% penetration ratios were approximately Class B and between Class C and Class D, respectively, per Japanese standards. Furthermore, results show that increasing the weld-penetration ratio can prevent root-to-throat fatigue cracks and enhance the fatigue resistance RD joints.