Behaviour of Transmission Lines Subjected to Tornadoes Through Aeroelastic Testing and Numerical Modeling
Abstract
Tornadoes, as a form of high intensity wind (HIW) events, represent major threats to transmission line systems in many regions around the globe. Transmission line systems are among the most vulnerable structures to tornadoes due to their expansion over hundreds of kilometers and, therefore, increased exposure to such localized wind events. A comprehensive research project has been developed over the past two decades at Western University to study this problem. The research conducted in this thesis provides a significant development to the advancement of knowledge in this area through achieving three main objectives. The first objective is to assess and quantify the contribution of dynamic resonant component to the peak responses of the transmission line towers and conductors. For this purpose, a set of aeroelastic tests on multi-span transmission line and transmission tower under laboratory-simulated tornadoes is conducted and using proper instrumentations the responses of the models are measured. Such aeroelastic testing of transmission line subjected to tornadoes has not been reported previously in the literature. The second objective is to validate the numerical model previously developed in-house at Western University using the experimental measurements. The third objective is to numerically assess the effect of the variation of the tornado wind fields within the same Fujita scale on the response of transmission line structures. Finally, a comparison is carried out between the structural responses due to numerically simulated real tornado events, when normalized to the maximum velocity range of F2 tornadoes, and those estimated through the application of the load cases recently implemented in the guidelines of transmission line loading of the American Society of Civil Engineers.