Portland General Electric’s Harborton Substation is located in Northwest Portland near Highway 30.

Crux was contracted to install micropile foundations for a structure location with liquefiable soils near the Willamette River.  After reviewing the available geotechnical information, lateral spread design requirements, and liquefiable soils, Crux provided multiple foundation solutions and associated risks of each type, ultimately determining that vibratory caissons would be the most cost and schedule effective.

Crux coordinated the design and oversaw the construction of the caissons.  Caissons consisted of three sections with two welded joints and were installed to depths of approximately 100 feet.  Soil was then removed by hydro-vac to allow for anchor bolt and concrete placement.  Specific challenges included limited and challenging geotechnical conditions, which were mitigated through the use of a CPT contractor prior to construction.  The project also involved limited working space, requiring coordination to maneuver the necessary large equipment and materials.