A stop-hole which is drilling at the crack tip is the temporary repair of fatigue cracks in steel structures. However, when the crack becomes longer, the stress concentration of stop-hole also becomes higher. So far, the authors proposed the technique to reduce the stress concentration at stop-hole by bolting the fatigue cracks. In this study, the effect of the proposed technique was verified by the bending fatigue test. From the result of fatigue tests, the fatigue life of stop-hole with bolting a crack becomes longer than that of the conventional one, even though the fretting fatigue of high-strength bolt or main plate was observed. Furthermore, the equation of stress concentration at stop-hole with bolting fatigue crack was proposed.
