Probabilistic Assessment of the Galloping Stability of Ice-Accreted Bridge Hangers

Galloping vibrations have recently been identified as a potential problem for ice-accreted bridge hangers. In this study, starting from wind tunnel measurements of the aerodynamic coefficients of an ice accreted HDPE cable hanger, the nature of the ice-accretion aerodynamics is shown. Then, a framework based on Montecarlo simulations is applied for the probabilistic assessment of the minimum structural damping required to prevent galloping of bridge hangers based on the output of a 2-DoFs sectional quasi-steady aeroelastic model. All the variables required to define the hanger dynamics, the sheath aerodynamics and the local wind climate are considered. The results highlight the advantages of the probabilistic procedure in terms of reliability quantification, compared to the deterministic approach.