The authors focused on the high strength bolted friction grip joints with countersunk head bolts which can finish the surface of the connection plate flat smoothly and prevent from functional depression due to corrosion. In this study, we carried out FE analysis varying the angle of countersunk head in order to evaluate the contact pressure of double shear connected friction joints with countersunk heads. Also, we have investigated the influence on load transferring mechanism by using countersunk head bolt for frictional joints. It has concluded that the most desirable angle of the countersunk head is 90 degrees. CD series's slip strength is about only 4% lower than that with normal head bolts.
