This report provides information to the overhead transmission line design community regarding current state-of-the-art practices employed to design long span/tall tower transmission systems. It includes a review of articles and publications relevant to long span/tall tower systems, a summary of survey results of systems already in service, and a critical review of codes and standards from the standpoint of conventional versus advanced analysis methods. The report offers a discussion of conventional versus advanced design practices. It indicates the need for research and further development on methods/formulae that will assist designers in determining when long span/tall tower system design models might become too complex to apply conventional practice methods and benefit, from a risk point of view. For example, the report includes recommending dynamic analyses of the very tall towers and more importantly of the towers and the attached long spans of attached wires as a system. It closes with suggesting criteria for addressing the unique challenges these facilities present.
Tall towers, Long spans, State-of-the-art design, Analysis methods, Design practice