Study on Reinforcement for Fatigue Cracking of Rib-to-Diaphragm Welded Joints of Steel Bridge Deck

In order to study the reinforcement effects of bolted angle steel on fatigue cracking of the orthotropic steel bridge deck, the full-scale test model was used to study the reinforcement effect of fatigue cracks on the rib-to-diaphragm welded joints. A finite element model with fatigue cracks was established using ANSYS, and to study the reinforcement effects under different length of fatigue cracks conditions based on the fracture mechanics theory. The results indicate that the fatigue cracks initiate from the toe of longitudinal rib-to-diaphragm welded joints and expand along the longitudinal web, the reinforcement method with bolted angle steel can reduce the main tensile stress of the key measure points at the cracking details and the strain of measure points at crack tips by 56% and 80%, respectively. The stress intensity factor of the crack tip is reduced by more than 80% after bolting angle steel reinforcement, and crack propagation rate is reduced significantly. For the different lengths of fatigue cracks before the longitudinal rib webs, the amplitude of the crack tip stress intensity factor is reduced by 60%−90% using the reinforcement method, but with the increase of the fatigue cracks length, the reinforcement effects are reduced continuously, the reasonable selection of the reinforcement time is one of the key factors in the reinforcement effects.