A Review on Behavior and Fatigue Performance of Orthotropic Steel-UHPC Composite Deck

Although orthotropic steel decks (OSDs) have been widely used in the construction of long-span bridges, there are frequently reported fatigue cracks after years of operation, and the bridge deck overlay also presents severe damage due to OSD crack-induced stiffness reduction. Ultra-high performance concrete (UHPC), recognized as the most innovative cementitious composites and the next generation of high-performance materials, shows high strength, ductility, toughness, and good performance on durability. After its first application to the OSD bridge in the early 2000s, the orthotropic steel-UHPC composite deck has been comprehensively studied worldwide. This review will summarize some important studies and findings on the behavior and fatigue performance of the orthotropic steel-UHPC composite deck. The existing studies and engineering applications indicate that such a deck system presents good bending behavior and high fatigue performance. The failure mode of shear studs in the UHPC layer is dominated by shear fractures. The cracking of the UHPC layer shall consider the superposition effect of stress from both the whole bridge structure and local decks. While some reasonable structural details in the traditional OSD may not work for the orthotropic steel-UHPC composite deck, this paper has shown that the steel-UHPC composite deck has excellent performance in bearing capacity, stiffness, and fatigue resistance. However, the fatigue performance of the steel-UHPC composite deck and its evaluation method still need validation from engineering applications. It is recommended to evaluate the stress behavior and structural parameters, as well as fatigue life by conducting the field test under in-service traffic conditions.