Fatigue evaluation for longitudinal-to-transverse rib connection of orthotropic steel deck by using structural hot spot stress

Orthotropic steel decks have serious fatigue problems especially on the connections between longitudinal and transverse ribs. In this paper, experimental and analytical works were conducted to evaluate the fatigue performance of connections between longitudinal U-ribs and transverse ribs with and without the slit on the transverse rib web. Finite element analyses of the specimen for all possible loading cases clarified the influence surfaces for structural hot spot stress (SHSS) working on weld toes of the connections. Fatigue tests with the loading case that generates the maximum and minimum SHSS on the connections were conducted. Fatigue test results for the slit connections evaluated by SHSS show agreement with previous fatigue data of similar connection details. No fatigue crack was initiated on the connection without the slit after 4.6 million cycles compared to fatigue failure of the slit connection at 0.7 million cycles.