In this paper, a new bolt axial force reduction coefficient was calculated and evaluated to assess the reduction in bolt axial force due to both increased cable tension and aging, with the aim of rationalizing the design methodology for intermediate joints. First, the change in bolt axial force due to increased cable tension was determined experimentally. Second, the coefficient of reduction of bolt axial force due to aging was calculated from the experimental results. Finally, a new bolt axial force reduction factor was calculated considering the above two experimental results and compared with the current bolt axial force reduction coefficient.
