The Maintenance Effect of Diaphragm-to-Rib Fatigue Cracks in Orthotropic Steel Deck via Steel Plate Reinforcement

To investigate the maintenance effect of diaphragm-to-rib fatigue cracks via steel plate reinforcement, finite element models of different-shaped steel plates were established. Stress intensity factors at the crack tip before and after reinforcement were obtained, and the variations in stresses were studied. Polygonal steel plate reinforcements were then carried out on a real bridge based on the finite element calculation results. The changes in stress amplitudes and fatigue damage degrees at the crack tip were analyzed via the rain-flow counting method and Miner’s linear damage accumulating theory. The results show that both the polygonal steel plate and the rectangular steel plate could effectively eliminate the stress concentration and restrain the propagation of cracks. The stresses in other parts of the arc notch increased after reinforcement and polygonal steel plates had less influence. After the reinforcement in a real bridge, the cycle number of high stress amplitudes at the crack tip decreased significantly. The fatigue damage degree of the repaired part reduced by 70.1%, which verified the maintenance effect via polygonal steel plate reinforcement on diaphragm-to-rib fatigue cracks.