Abstract
In steel railway bridges, a fillet radius of flange gusset was r=20mm and was very small radius at time when all welding bridges were adopted firstly. Fatigue strength of this flange gusset belongs to F category (65MPa) in newly design code. Moreover, there are location where the stresses which exceeds F category are measured in actual bridges. Fatigue cracks have not been reported from this corner yet. But the fatigue crack of this type propagates in lower flange and cuts lower flange, it leads to web. In this paper, experiment and analyzed are done to relieve of stress concentration and introduce compressive residual stress for improvement of fatigue strength of flange gusset corner. As a result, it was clear that relief of fillet radius and peening of fillet corner are both effect for improving of this fatigue strength.
