Aerodynamic action on inclined stranded cables in cable-stayed bridges

A very recent fatigue collapse of an inclined stranded cable of the Sabo footbridge has left unanswered questions regarding its underlying origins. Vortex shedding of the cable, which was initially suspected to be the cause, is nominally thought of being severely weakened due to the stranded section and the inclination. Thus, buffeting, galloping or some other hybrid aerodynamic mechanism look as more plausible explanations. Overall, there is confusion and limited experience on identifying and mapping wind-induced vibrations of inclined stranded cables and this is where this proposed research attempts to have an impact. A meticulous experimental multi-scale study coupled with CFD simulations that could reproduce observed behaviours seem as the best option to replicate and understand in depth the problem in-hand. Wind/water-tunnel tests combined with monitoring of real-scale bridges would cover the experimental side of a work which is to use different CFD numerical options with the goal to uncover their limitations. State-of-the-art experimental and analytical tools are to support this research endeavour, which will be fundamental by generalising outcomes, focusing on uncovering shortcoming of the past and shedding light to newly recognised aerodynamic phenomena such as large structural motion owing to flow bistability and intermittency.