In 2002, Kaiser Permanente constructed a four-story, five-level parking structure on the Sunnyside Medical Center campus in Clackamas, Oregon. GRI evaluated subsurface conditions at the site and provided the design team with recommendations for earthwork and site preparation, excavations and groundwater control, floor support and subdrainage, and design of embedded walls. A site-specific seismic hazard study was performed in accordance with the Oregon Structural Specialty Code. The subsurface investigation disclosed the site is underlain by weathered basalt at relatively shallow, but highly variable, depths. Although several other large structures on the campus are supported on augercast piles installed to the underlying basalt. The significant variability in the depth and consistency of the rock and presence of boulder-size rock fragments at the parking structure site made augercast piles or other deep foundations such as drilled shafts difficult to install, and driven piles were not an option due to noise. Considering site conditions, it was determined the structure could be supported on spread footings. GRI provided geotechnical criteria for footing design and provided on-site observation service and consultation during construction.
GRI has provided statewide geotechnical services for Kaiser Permanente since 1984, including numerous phases of expansion at Sunnyside Medical Center and new Westside Medical Center in Hillsboro.