Review of the damage equivalence factors for steel railway bridges in the Eurocodes

Proper fatigue design is essential for the sustainable operation of bridge structures. The fatigue design concept in the Eurocodes follows the damage equivalent concept allowing to conduct this relatively extensive design check as efficiently as possible. However, those factors cover a rather complex phenomenon and the code provides them in a standardized format. The actually required values are typically lower, but the parameter calibration and the included reserves are non‐transparent from the design standards.

The objective of this paper is to recall the methodology for calibration of the damage equivalence factors and to review the damage equivalence factors given for steel railway bridges in EN 1993‐2. After a discussion on the assumptions in the Eurocode in context with the damage equivalent concept, the presented methodology is applied to recalculate the damage equivalence factors for the railway traffic spectrums in Eurocode 3. The obtained results verify the damage equivalence factors in the Eurocode 3 and figure out the span‐dependent safety margins in those factors. To investigate the influence of the traffic spectrum, the damage equivalence factors were also determined for a traffic spectrum provided by the Swiss national railway authorities for comparative purpose.