Evaluation of Eurocode damage equivalent factor based on traffic simulation

The Eurocodes provide a simplified fatigue design control through the use of Fatigue Load Model 3 (FLM3) and a damage equivalent factor, λ, which is now widely used. In applying the Eurocode method, the first problem arises when designers try to determine the corresponding fatigue span length, especially for bridge static systems not listed. A second problem is that in case of long bridges, the probability of having several heavy vehicles simultaneously over the bridge exists (in single lane traffic as well as in multilane traffic), which results in larger cycles and, accordingly, higher contributions to total damage. This paper first evaluates the damage equivalent factors and then provides an all-inclusive method for determining the fatigue critical length for any bridge static system and the corresponding damage equivalent factor. It proposes modifications for improving the fatigue design method using damage equivalent factors. Figure 1. Procedure of determination of damage equivalent fac-