Asian Counseling Building

The project is a building that has three stories above ground with two stories below ground.  The site is an area of old, loosely-placed fill with debris.  Significant ground water was encountered within the fill.  Soils underlying fills were easily disturbed silts.  Cornerstone provided design consultation and construction observation.

Salmon Bay Marina

This renovation of a previous shipyard and repair facility includes both onshore office and warehouse structures in addition to floating docks.  The office structures required installation of 18-inch-diameter auger cast piles.  The floating docks are anchored in place using up to 20-inch-diameter steel pipe piles.

Rattlesnake Mountain Communications Tower

Located near the summit of Rattlesnake Mountain in Snoqualmie, this three-legged, 275-foot-tall, steel-lattice communications tower was initially planned to be founded on three 8-foot-diameter drilled shafts, which were to extend 50 feet into the underlying highly-weathered bedrock.  We explored the subsurface conditions by drilling three borings to depths of up to 44 feet and then conducted a vertical capacity analysis and provided capacities for various-sized drilled shafts.  Our analysis and resulting recommendations enabled the tower to be founded on substantially less expensive, 6-foot-diameter, 37-foot-deep drilled shafts.  We also observed and documented the installation of the drilled shafts.

Perrigo Park

Cornerstone Geotechnical was retained near the end of the project to complete groundwater mounding analysis of the  on-site stormwater infiltration system.  This work was completed to satisfy the King County stormwater design criteria for infiltration systems.

Cingular Building

As part of an upgrade to disaster preparedness, the Cingular Company installed an addition to one of their buildings to house new generators.  The building is located in the North Creek area of Bothell.   They also installed an additional 40,000 gallon underground fuel storage tank.  The project site was underlain by 12 to 20 feet of peat, requiring the use of auger cast piling.  The tank excavation required steel sheet piling and dewatering wells.

Foundation House

Geotechnical consultation and construction observation at a senior-living center in Bothell.  The site access road had an alignment along a slope and crossed a known deep-seated landslide in low-strength silt soils.  We prepared a design to improve the stability of the slope above and below the access road using soil-cement filled trenches.

Homewood Suites Hotel

Located in Seattle, the project included the construction of a 26-foot-high soldier pile wall with tiebacks allowing excavation cuts to the property lines. A portion of this shoring wall also acted as underpinning for adjacent building. We provided drilled-pier design recommendations, in addition to construction observation and consultation services during construction.

Garden Grove

Garden Grove is a mixed-use commercial development consisting of a senior-living center, office buildings, and a large self-storage facility. Subsurface conditions at the site included old fill, silts, glacial till, and buried topsoil. A combination of overexcavation and the installation of concrete piers solved the variety of problems posed by the subsurface conditions.

University Child Development School

We conducted a soil investigation and provided construction observation services for the school’s new building and playground. The unique architecture and the terrain of the site made foundation construction very challenging. Cornerstone Geotechnical, Inc. was named as “special inspectors” for the project and made economical consultation recommendations regarding the use of on-site soils.

Campbell’s Soup Landslide Repair

This project involved the repair of a deep-seated landslide behind the Campbell’s Soup facility along Highway 9 that threatened BNSF railroad tracks. The challenges posed by this site included artesian conditions below the slide. Using back calculations from field measurements, we established soil parameters to aid our design of large-diameter concrete piers to support the  landslide mass. We also provided construction observation services and installed instrumentation to monitor future slope movement.

Shoring for Mixed-Use Building

This three-story mixed-use building in Edmonds needed a 12 foot cut for an underground parking garage. The proximity of the excavation to neighboring structures required the use of temporary shoring during construction. During the installation of the soldier pile shoring wall, we evaluated soil and groundwater conditions encountered and provided recommendations for drainage.

Woodland Meadows

This residential development in Bothell, built primarily on a hillside, located three homes over a pre-existing filled pond. We mapped subsurface peat deposits as deep as 18 feet. These houses were founded on deep auger-cast piers embedded in the dense material underlying the peat. We provided depth recommendations and construction observation services for the pier installation.