Assessment of an Orthotropic Deck Detail of Road Bridges for Fatigue According to the 2nd Generation Eurocodes

Fatigue cracks have been identified in key structural details of the orthotropic deck on the SNP Bridge - the bridge with the longest span in Slovakia – crossing the Danube River in Bratislava. These cracks were observed at welds connecting the closed stiffeners to the deck plate, the discontinuous stiffeners to the crossbeam web, and at the stiffener splices.

This paper evaluates one of these critical fatigue-prone details (stiffener to deck plate) using various fatigue assessment methods outlined in the draft of the forthcoming EN 1993-1-9 standard on fatigue. The nominal stress, hot-spot stress, and effective notch stress approaches were applied for verification. The traffic loading history over the bridge’s service life was approximated using current traffic data, primarily municipal bus transport. Fatigue life estimates derived from the three design approaches are presented and compared, with an in-depth discussion of the differences and implications for fatigue assessment and design.