The purpose of this study is to estimate the stress introduced in steel plate with thickness-reduced section repaired by patch plates with high-strength bolts. First, to investigate the tendency of stress in thickness-reduced section, finite element analysis was carried out with several parameters of thickness and length of thickness-reduced section. Then, a simple equation of stress introduced in thickness-reduced section in steel plate repaired by patch plates with high-strength bolts was proposed. Additionally, the tensile tests of steel plate with thickness-reduced section repaired by patch plates with high-strength bolts were conducted to verify the availability of proposed equation.
