Abstract
High strength bolted friction type joints are often used for the site connections of members in steel bridges. A bolt used for the joint is generally 8T or 10T class one. The slip resistance of the joint is determined by multiplying a slip coefficient factor by a bolt axial force. The bolt force is introduced dependent on the tensile strength of the bolt. The 14T class bolts with higher tensile strength are recently used. The slip coefficient factor for a design of the bolted connection is specified as a single value independent of a bolt axial force. However, it is confirmed by recent studies that the friction factor decreases as contact pressure becomes high. Therefore, as for the joints with 14T class bolt, it is necessary to use the slip coefficient factor lower than one established for the joints with conventional 10T class bolts. In this study, slip coefficient factor according to bolt tightening force has been made clear through slip tests and FE analyses on the joints with 8T, 10T and 14T class bolts.
