Vertical Effects of Large Cable-Stayed Bridges

Vertical effects significantly affect the design and static analysis of large cable-stayed bridges. In the design of large cable-stayed bridges, the impact of cable sag must be considered. Generally, the Ernst equation is suitable when considering the cable sag effect for small spans (or the ratio of cable weight to tension). The Ernst formula assumes that a sag is a parabola curve and disregards the components of gravity. This assumption is inaccurate for some large-span bridges, and other accurate algorithms must thus be considered for analysis. In this work, the gravity and tensile force of cables are considered for long-span cable-stayed bridges. Furthermore, the effects of gravity on the directions of normal cables are considered. Analyses show that the gravitational components for cable directions should not be disregarded if the ratio of cable weight to tension force is large.