Micropile Foundations | Geotechnical Construction
Miguel - Mission Transmission Line
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Project Description
The Miguel-Mission 230 kV Transmission Line Project included the addition of a single-circuit 230 kV line, and the relocation of an existing 138 kV line and 69 kV line onto new poles within the existing San Diego Gas & Electric (SDG&E) right-of-way. The project was designed to address current and future overloads on SDG&E's existing electrical system, which only included the 69 kV and 138 kV lines. The project was located entirely within San Diego County, passing though both San Diego and Santee, CA.
Team Members
San Diego Gas & Electric, PAR Electrical Contractors Inc., Crux Subsurface Inc., Dryden & Larue Inc.
Crux’s Role
Crux was contracted to provide design-build services for five transmission tower foundations on the project. Foundations were designed and constructed utilizing a radial array of battered micropiles in combination with an all-bolted steel pile cap. Two micropiles at each foundation were tested to their maximum factored design load for quality assurance. Additionally, galvanized micropile components, hardware, and pile caps were utilized to minimize the potential for corrosion over the design life of the foundations.
Crux’s micropile foundations were selected as an alternative to conventional drilled shafts because of their ability to be constructed using only helicopter transport. Road construction in the area was deemed as too risky due to the potential for rock slides within close proximity to downhill residences.
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To request additional information, please use our Contact Page or call 866-CRUXSUB (866-278-9782).
