Considerations in Guyed Engineered Steel Structure Design

The power transmission industry has grown increasingly interested in new approaches to generate economic design. For high-voltage transmission lines, opportunities for greater efficiencies exist primarily in structure design. Guyed engineered steel poles have become a desirable option for those seeking to minimize cost while satisfying performance requirements. Lightweight and easily erected, guyed steel poles minimize structure deflections and can ordinarily be built on relatively economical foundations. Because they depend upon a complex system of load transfers, however, guyed engineered steel structures introduce many unique design considerations. For instance, engineers must calculate how a load will transfer from the structure to the guy wire to the anchor, as well as how it will transfer from the structure to the foundation. They need to determine how construction tolerances will be accounted for in the design and the feasibility of accomplishing this added design work without significantly increasing cost. They must consider which decisions impact cost and add margin to the design, as well as what could potentially limit the proposed guy wire size. They must determine if guy loading should be limited to reduce anchor size and related installation costs. They must verify the ready availability of hardware that meets strength requirements. Failure to acknowledge these design considerations can result in lost efficiencies, construction schedule delays, or inadequate performance. Drawing on their years of high-voltage transmission line experience, the authors examine key design considerations on projects where guyed engineered steel poles were used and discuss approaches to account for these considerations in coordination with steel suppliers.