Mitigation of Wind Induced Vibration in Substation Structures: A Field Monitoring Study on a Full-Scale A-frame with Curved Spoilers

摘要

Wind induced vibrations have become increasingly important in recent years, as designers have used materials to their limits, causing structures to become progressively lighter, more flexible, and prone to vibration. Because of their slenderness, flexible design and low damping ratios, A-frame structures are susceptible to wind-induced vibrations. These vibrations cause structural stresses and strains to develop in a cyclical fashion, which can lead to reduced service life due to fatigue, and, in extreme cases, full collapse. Recently, there has been a report of severe vibration on a substation structure. As a result, a project has been completed to first investigate the reason of vibration, then to come up with a solution, and finally help prevent it in other structures. A full-scale experiment was conducted on the vibrating A-frame structure, located in Fort Wayne, IN, in which the response of the structure was observed in relation to in-situ wind conditions for ten days. In a previous study conducted by the same authors, the same A-frame was examined numerically using two-way 3D fluid structure interaction (FSI) simulations in ANSYS Workbench with and without curved spoilers. It was evident that using curved spoilers would be an effective approach to mitigate the Vortex Induced Vibration (VIV). In this paper, the different project stages are explained and the results are presented. First, the theory of VIV is explained, then the simulation methods are shown and compared with observations, and finally the mitigation method used for the structure explained.