组合桥面板U肋对接焊缝疲劳破坏及修复方法试验

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

摘要:

为了研究弯折U形肋组合桥面板的疲劳性能以及疲劳开裂后的修补方法，对一个带连续弯折U形肋的组合桥面板试件进行了前后两次疲劳试验研究.首先对初始采用无衬垫对接焊缝的试件进行疲劳加载直到焊缝开裂；然后在开裂处采用带衬垫的对接焊缝加固，再次进行疲劳加载直到破坏.研究了组合桥面板疲劳破坏形态、开裂处疲劳强度评定、疲劳裂缝修复方法及修复后的疲劳性能.试验结果表明：在反复荷载作用下无衬垫单面焊的对接焊缝是正交异性组合桥面板的薄弱处，首先发生疲劳裂纹，采用带衬垫的熔透对接焊缝对开裂处进行修补，能起到较好的补强效果.

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.