ABSTRACT
Fatigue loads and load effects are important aspects of the safety and resilience for many bridges. Long-span bridges are commonly designed with orthotropic steel deck bridge girders for weight optimization. Such bridge decks may be subjected to significant fatigue loading from heavy vehicle traffic, and in some cases the fatigue limit state will even be dimensioning for the stiffened deck plate. Typically, local wheel loads are assumed to dominate the fatigue stresses, and fatigue damage is calculated based on hot spot stress from local analyses. However, with increasing span length, global load effects from both traffic and environmental loads will increase in significance. This is particularly relevant for floating bridges, where the environmental loads may significantly contribute to the fatigue damage. Also, as more extreme suspension bridges and cable stayed bridges are sought, the combination of local and global effects will be important. With fatigue damage being highly nonlinear, fatigue analysis due to combined load effects is a challenging task, and a coupled approach is typically necessary to achieve sufficient accuracy. In this paper, a method to generate stochastic time series of hot spot stresses due to local and global load effects from traffic is proposed. The method is suitable for combination with other fatigue-driving load effects, achieving a reasonable total computational cost while maintaining accuracy.
