| During the past years, many electrical transmission lines have failed during downbursts. This thesis is part of a research program aimed to understand the behaviour of transmission lines under localized winds. The first part of the thesis assesses the dynamic behaviour of the conductors under downburst loading. A non-linear numerical model is utilized to predict the natural frequencies and mode shapes of the conductors at various loading stages. A turbulence signal is added to the mean component of the downburst wind field previously evaluated from a CFD analysis. Dynamic analysis is performed using various downburst configurations.;The fourth part of the thesis involves studying the behaviour of self supported transmission line towers under downburst loading. A parametric study is performed to determine the critical downburst configurations causing maximum axial forces for various members of the tower. The sensitivity of the internal forces developing in the tower's members to changes in the downburst size and location is studied. The structural behaviour associated with the critical downburst configurations is described and compared to the behaviour under normal wind loads.;KEYWORDS: Downburst, High Intensity Wind, Transmission Line, Transmission Tower, Finite Element, Failure, Turbulence;The second part of the thesis focuses on evaluating the sensitivity of the forces in the members of guyed towers to changes in the downburst configuration, tower height, guys' configuration, turbulence, and the conductors' pretensioning force. The axial forces in the members are compared to those resulting from normal wind loading and the broken wire load case. |
