Abstract
Imperfect Penetration (IP) defect is one of the worst defects which could be occurred
in the steel bridges. IP defect of tension region of steel girder would induce stress concentration
at the tip and eventually could develop cracks at that point. So, many researchers have recommended to fully investigating the welding quality of tension region of steel girder when performing
in-depth inspection of the steel bridge and, if IP defect was found, it is needed to perform more
detail investigation, such as core test, ambient stress measurement, and fatigue lifetime estimation.
Then, we should determine whether the repair should be needed or not.