Effect of SFRC pavement on root-deck crack propagation in orthotropic steel decks

This study analytically investigated the behavior of root-deck cracks in orthotropic steel decks and the suppression effect of steel fiber reinforced concrete (SFRC) pavement on their propagation. These cracks, which initiate at the root of the rib-to-deck welded joint, were modeled using actual structural details and loading conditions, along with test-derived parameters such as crack direction and aspect ratio. The validity of the models was confirmed by comparing the changes in strain range near the welded joint and crack propagation angles based on the dominant stress intensity factor (SIF) range with experimental results. Fatigue life calculations based on experimental and analytical results revealed that once a root-deck crack reaches a significant depth, another crack could initiate from the deck surface and eventually merge with the first crack due to increased stress. Furthermore, the analysis confirmed that the application of a 75 mm thick SFRC pavement effectively suppresses crack growth. The SIF range remained below the threshold regardless of the remaining crack depth, and the SFRC pavement also prevented crack initiation from the deck surface.