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INSTRUCTORS:
Michael D. Miller, P.E., P.Eng, F.SEI, F.ASCE
John Klotz, P.E.
Evan Morris, P.E.
Shravani Talabathula
Garrett Luszczki, PE
Purpose and Background
These presentations were recorded at the Electrical Transmission & Substation Structures Conference 2025.
Rehabbing vs Replacing Existing Lattice Towers? Case Study: LG&E-KU Ohio Falls River Crossing Towers (22 minutes)
This presentation explores the engineering and historical significance of the 1927 Ohio Falls River Crossing Towers in Louisville, Kentucky, and the critical question of whether to rehabilitate or replace them. The presenter examines corrosion issues in century-old riveted copper-infused steel towers, the earliest known use of weathering steel in utility structures. Using advanced 3D photogrammetry and PLS tower modeling, the project team captured geometry and quantified structural deterioration with high precision. The talk highlights innovative remediation strategies inspired by bridge engineering practices, including joint sealing with high-performance polymer coatings. Construction access and scaffolding solutions are discussed alongside probabilistic wind load assessments to manage risk during rehabilitation.
Micropiles Provide Economical, Environmentally Friendly Solution In Challenging Terrain (18 minutes)
This case study showcases how Dominion Energy and Schnabel Engineering used micropile foundations to overcome access, environmental, and permitting challenges during a 9-mile 115 kV transmission line rebuilt through Virginia’s mountainous national forest. Traditional foundation options, direct embedment, grillages, and drilled shafts, proved impractical due to steep terrain and shallow rock. The project team developed a new foundation system using above-ground steel grillages supported by micropiles, minimizing environmental footprints and access to road construction. Collaboration among engineers, geotechnical experts, and contractors enabled innovative solutions that balance cost, constructability, and permitting constraints. Field testing and design iteration refined the use of hollow-core bar micropiles and optimized installation techniques. The project demonstrated that non-traditional foundations can significantly reduce overall project costs and environmental impacts while maintaining reliability.
Saving Space: New 115kV Spacer Cable Technology vs. Traditional Open-Wire Systems (23 minutes)
This joint presentation from TRC and Marmon Utility introduces a breakthrough 115 kV spacer cable system that provides a compact, reliable, and wildfire-resistant alternative to traditional open-wire transmission. The covered-conductor spacer system combines the mechanical benefits of overhead lines with the electrical resilience of insulated systems, reducing right-of-way width by up to 70%. Presenters discuss the evolution of spacer cable technology, key design features, installation methods, and field performance data from pilot and full-scale installations. A commercial comparison between spacer cable and open-wire construction demonstrates significant reductions in pole height, EMF, and voltage drop. Modeling approaches using PLS-CADD are shared, including lessons from the first 115 kV installation for Liberty Utilities in New Hampshire. Attendees will learn about cost implications, constructability, and long-term monitoring outcomes. This presentation underscores the system’s potential to modernize compact transmission corridors while improving reliability.
Benefits and Learning Outcomes
Upon completion of this course, you will be able to:
- Explain how 3D photogrammetry and PLS modeling can be used to assess structural condition and load performance in legacy lattice towers.
- Describe the economic and engineering considerations that inform decisions between rehabilitation and replacement of critical infrastructure.
- Describe the advantages of micropile foundations for transmission structures in difficult terrain.
- Identify how multidisciplinary collaboration and adaptive construction methods can mitigate permitting and access challenges in environmentally sensitive areas.
- Explain the design principles and performance advantages of 115 kV spacer cable systems compared to traditional open-wire configurations.
- List key design and modeling considerations for implementing covered-conductor systems in constrained rights-of-way.
Assessment of Learning Outcomes
Students' achievement of the learning outcomes will be assessed via a short post-test assessment (true-false, multiple choice, and/or fill in the blank questions).
Who Should Attend?
- Utility Engineers
- Structural Engineers
- Consulting Engineers
- Contractors
- Suppliers & Manufacturers
- Researchers & Educators
How to Earn Your CEUs/PDHs and Receive Your Certificate of Completion
To receive your certificate of completion, you will need to complete a short post-test and receive a passing score of 70% or higher within 1 year of purchasing the course.
How do I convert CEUs to PDHs?
1.0 CEU = 10 PDHs [Example: 0.1 CEU = 1 PDH]