Impact of Stiffness on the Cable Force of Cable-Supported Bridges

Generally, cable-stayed bridges are long-span bridges, and their consisting cables have been confirmed as the main load-bearing components. Hence, an accurate evaluation of cable forces is vital to determine the stress state of bridges. Considering the effect of stiffness on cable force and determination of short cable in practical engineering, cable length, slenderness ratio, and characteristic parameters in the existing specification are taken into account via a specific parameter, represented by ξ. The effect of cable stiffness on cable force serves as a variable, which requires further investigations. As indicated by the research results, the effect of the cable bending stiffness on the cable force reduces with increasing the cable length, slenderness ratio, and cable characteristic parameter ξ. For cables under hinged boundary conditions, the stiffness contribution to the cable force reaches more than 5% for cable lengths less than 6.5 m. Under fixed boundary conditions, the stiffness contribution to the cable force exceeds 5% for cable lengths less than 11 m. Short cable determining criteria are proposed according to the analysis results. In addition, the ranges[DK]' values of the cable length, slenderness ratio, and ξ factor of short cables are given. The achieved results suggest that cables less than 11 m in length should be conservatively defined as "short cables". Further, complementary analyses reveal that the cables with a slenderness ratio less than 175, and ξ-factor lower than 23 can be classified as short cables.