Fatigue strength of cope hole details in steel bridges

Cope holes found at the intersections of steel structural members to access crossing welds may cause high stress concentration and decrease the fatigue strength of the detail. In this study, fatigue strength and local stresses for cope hole details existing in I-section beams bent in-planes were investigated by fatigue tests, stress measurements and stress analyses. The experimental results showed the fatigue strength of cope hole details was extremely low due to the local stress around the cope holes. In particular, when shear deformation was induced in a gap of flange plate inside a cope hole, the local stress was greatly increased. Using an analytical approach, the relationship between the magnitude of local stress and some influential parameters was investigated and a simple method to estimate the local stress for cope hole details is proposed.