INFLUENCES OF TYPES OF JOINTS AND PLATE THICKNESS ON A NEW BOLT-TIGHTENING METHOD IN WHICH THE FINAL TIGHTENING IS EXECUTED 24 HOURS AFTER THE TEMPORARY TIGHTENING

Abstract

 It is known that high strength bolted joints treated with thickness-type zinc-rich paint and have a characteristic of large bolt pretension loss by relaxation that the bolt axial force often drops below the design axial force. Therefore, we had proposed a new bolt-tightening method, in which the final tightening of the bolts is executed 24 hours after the temporary tightening. However, influences of types of joints and plate thickness are not clarified. In this study, the friction type of high strength bolted connection specimens, in which contact surfaces are inorganic zinc-rich paint, were made considering these influences. Then slip tests and relaxation tests were carried out on these specimens. From these results, we discussed the applicability of proposed bolt-tightening method considering types of joints and plate thickness.