The purpose of this study is to evaluate the stress introduced in steel plate with asymmetric defects repaired by patch plates with high-strength bolts. First, to investigate the tendency of stress in the thickness-reduced section, finite element analysis was conducted. From analysis results, the stress introduced in defect repaired by patch plates does not correspond with the one calculated by the composite theory of defected part and patch plates. Then, a simple calculation method of stress introduced in steel plate with asymmetric defects repaired by patch plates was proposed using the frame structure analysis. Finally, the range of application of the simple calculation method was discussed in comparison with the result of finite element analysis.
