The authors focused on a highstrength bolt friction joint with a countersunk head that can smooth the joint surface and prevent functional deterioration due to corrosion. In this study, the slip behavior and maximum resistance of a joint with a long bolt were investigated. It was concluded from the experimental result that the slip coefficient did not change because only a small amount of yielding around the slip coefficient does not change because only a small yielding occurs around the bolt holes when the bolt is long. Although the bolts failed in only one shear plane, there was no significant reduction in maximum bearing capacity compared to the design value of two-plane shear failure.
