Experiment Research on Fatigue Failure and Repair Method of Butt Weld in UShaped Rib of Composite Bridge Deck

Abstract:

In order to study the fatigue property and the repair method of butt welds in folded Ushaped steel rib of composite bridge deck, a composite deck specimen has been tested twice, an original state and a repaired state, for fatigue character research in this paper. In first test, the specimen used butt welds without backing plate on the connection of the Ushaped ribs was loaded repetitively until a crack appeared. Then the butt welds with backing plate were applied to repair the fatigue crack. And after that, the second fatigue test was carried until the new weld crack appearing. The fatigue failure mode of composite bridge deck, fatigue strength of butt weld for folded Ushaped ribs, repair method of fatigue crack and the fatigue property after reinforcement were tested carefully. The results show that butt welds without backing plate are the vulnerable position of the composite bridge deck under cyclic loading, and fatigue crack appeared in this position first. Adopting butt welds with backing plate to repair the cracked welds is an effective reinforcement method.

Key words:composite bridge deck; fatigue test; stress amplitude; repair