A STUDY ON INITIAL BOLT PRETENSIONS OF HIGH STRENGTH BOLTED JOINTS CONSIDERING NUMBER OF CONTACT SURFACES

Abstract

 It is known that high strength bolted joints treated with zinc-rich paint and filler plate have a characteristic of large bolt pretension loss by relaxation. However, characteristic of bolt pretension is not clarified. In this study, the friction type of high strength bolted connection specimens with filler plate were made on steel plates, in which contact surfaces are to be rough without mill scale and have inorganic zinc-rich paint, then slip tests and relaxation tests were carried out on these specimens. From these results, we discussed the initial bolt pretensions on high strength bolted joints considering number of contact surface and condition of contact surface.