STUDY OF INFLUENCE ON SLIP COEFFICIENT OF HIGH STRENGTH BOLTED FRICTION TYPE JOINTS BY PAINTING CONDITION AND EXPOSURE TERM

Abstract

 High strength bolted friction type joints are generally used for connecting steel members at construction site of steel bridges. In case of high strength bolted friction type joints, quality management of bolt axial force and joint surface condition is very important in order to assure the slip coefficient (0.45) specified in the design code. In this study, in order to clarify the influence on slip coefficient of high strength bolted friction type joints by painting condition and exposure duration, a series of slip tests was carried out. Parameters in the slip test are thickness of the inorganic zinc-rich paint, difference by paint company and exposure duration. As results, it was found that slip coefficients of test specimens with paint thickness of 50μm or 150μm exceeded 0.45, and they became higher by longer exposure duration after bolting.