Behavior and fatigue life assessment of orthotropic steel decks: A state-of-the-art-review

Orthotropic steel decks (OSDs) have been commonly used worldwide in medium and long-span steel bridges due to their exceptional structural properties, such as lightweight, high -load carrying capacity, and easy construction. However, the fatigue performance of welded details in OSDs is reported as the key issue related to the design of this type of structures. This paper provides an overview of the theoretical background of the structural performance of OSDs. In addition, the fatigue behavior and fatigue assessment approaches of fatigue-prone details in OSDs are briefly introduced for deep understanding and accurate evaluation of their fatigue performance. Furthermore, several fatigue strengthening methods applied to the OSDs were presented. Literature reviews show that the fatigue performance of OSDs could be effectively evaluated by both the hot spot stress method and the notch stress method rather than the nominal stress approach. Regarding the fatigue strengthening, several approaches have been introduced, among which using UHPC overlay is well documented to enhance the fatigue strength of details in OSDs. However, the fatigue cracks observed at the floorbeam cutout detail need more consideration to further improve its fatigue resistance. Welding residual stresses significantly affect the fatigue life of details in OSDs and their effects should be considered in the design practice of such deck structures for more accurate fatigue life predictions.