A unified fatigue life evaluation method for different failure modes of the repaired rib-to-deck joints in orthotropic steel decks

Abstract

The rib-to-deck welded joints in orthotropic steel decks (OSDs) are prone to fatigue damage with different fatigue failure modes. The damage accumulation of the corresponding failure modes should be estimated in repair design. This study proposed a unified fatigue life evaluation method for different failure modes of rib-to-deck welded joints based on the structural stress method and linear damage accumulation theory. The method considers the effect of crack depth and crack propagation on life evaluation, validated by the tests of repaired rib-to-deck joints with interior repair welds. Damage accumulation before and after repairing corresponding to different failure modes was assessed. The dominant failure modes before and after repairing were analyzed. Finally, the damage accumulation law of welded joints after repair under standard traffic load was investigated based on the existing damage status of each failure mode of the rib-to-deck welded joint. The results indicate that the failure mode will transfer from root-deck to exterior toe-deck at the rib-to-deck joint after the interior repair welding. The dominant failure mode of the repaired joint is governed by the existing damage status and the repair method.