In 2002 Georgia Power began final engineering on a new 500kV single circuit transmission line. Given the amount of time that passed since the last major 500kV project, Georgia Power found it necessary to make investigations into areas where technological advances in engineering tools could provide possible cost reductions. In any transmission line project using rigid base towers, for example, foundation costs will most likely be a substantial part of the overall cost of building the line. For Georgia Power's Mosteller Springs-McGrau Ford 500kV transmission line, the estimated foundation costs made up 21% of the total estimated construction cost for the entire project. Although Georgia Power has historically designed foundations using the tower's ultimate design loads, this was identified as an area of potentially significant cost savings. With sophisticated transmission line design software and minimal additional effort by the engineer, the foundations could, in effect, be optimized when designed using site or leg specific tower loads. This paper evaluates Georgia Power's new procedures for specifying foundation design loads for rigid base towers. An analysis of the methods for specifying these loads will determine their respective impact on the foundation's design and overall cost.
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