Several structures within Olympia Substation, located approximately 6 miles southeast of Olympia, WA, were identified as exceeding their rated capabilities and needing replacement. Structures included three 500 kV disconnect switches, three 500 kV insulators and one 500 kV station service panel.

Bonneville Power Administration (BPA) selected Crux to provide engineering, procurement, and construction (EPC) services for seven micropile foundations to support the new structures. Locations included areas with challenging access and tight working spaces, requiring compact drills and ancillary equipment.

In addition to navigating the tight spaces, challenges included working under energized overhead lines when necessary and coordinating outage requirements with the owner. Crux’s track-mounted micropile drills were fully operational at less than 11 feet high, well within the required height restrictions, allowing for safe and efficient installations. Standard penetration testing (SPT) was completed during construction to accurately characterize site-specific subsurface conditions and optimize pile lengths and quantities, as well as the grouting method, required for each structure.

In total, 31 micropiles were installed to depths of up to 110 feet. All work was completed on time with zero safety incidents.