Cable aerodynamics
Long-span bridges are normally designed as cable-supported structures, in which cables in different arrangements support bridge deck and transmit the dead, service and environmental loads to supports and foundations. While cables are essential for safe operation of a bridge, they are extremely sensitive to various types of dynamic excitation and thus susceptible to fatigue and other types of damage. The wind-induced vibrations of cables include phenomena such as rain-wind vibrations of stay cables, dry cable galloping, parametric excitation, tower wake excitation of hangers, vortex-induced vibrations, ice- wind vibrations etc. Improved understanding of various types of the vibrations is vital for their effective suppression, by establishing necessary levels of damping to prevent the excessive response. We are involved in the joint international research focusing on the aerodynamic countermeasures to limit the galloping cable vibrations. A novel cable surface design has been proposed and will be further optimized. Since 2019, we have been monitoring the acceleration response of selected stay cables at Stavanger City Bridge, along with the weather data and bridge deck vibrations. The main focus of the measurement campaign developed in collaboration with the local road authorities is investigation of the occasional rain-wind induced cable vibrations. In September 2021, we will host the second International Symposium on Dynamics and aerodynamics of Cables (ISDAC2021).