Phone: 425.415.0551

Fax: 425.415.0311


Riley Group Corporate Office

17522 Bothell Way NE

Bothell, WA 98011

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Hyde Square

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This development consisted of four multi-family residential buildings each with a two-level below-ground parking garage on a site of 185,000 square feet in the City of Bellevue. The project began with demolition of a three buildings on the property—a retail space, a restaurant, and a bank.  RGI was asked to provide geotechnical recommendations for the site in early 2015 and has been involved in the project on an ongoing basis, since that time.

RGI provided full geotechnical services for this project and construction monitoring processes during the earthwork. In the beginning of the project, RGI conducted six borings to approximate depths of 25 to 35 feet below existing site grade. These samples were tested for moisture content and grain size to aid in soil classification, as necessary to formulate foundation and shoring recommendations. In addition, RGI participated in field exploration, sent samples for lab testing, provided an engineering analysis, and produced a final Geotechnical Engineering Report.

Geotechnical challenges for this site included a steep slope on the western edge of the property that was deemed to be a landslide hazard and, thus, had to be removed during development.  Max excavation was to a depth of 32 feet, which necessitated use of temporary shoring.  During construction, there were issues with standing surface water, necessitating the development of drainage and surface water guidance.

Geotechnical services included

  • Soil classification
  • Characterization of groundwater conditions
  • Pavement and slab-on-grade recommendations
  • Erosion control best management practices for both during construction and for the long term
  • Foundation design recommendations, including numerical design measures
  • Vault waterproofing guidance inclusive of specific ad mixture
  • Design plan approval for shoring and foundation
  • Drainage and surface water control direction
  • Utility suggestions

Construction monitoring services included

  • Shoring recommendations to ensure stability and erosion control during construction
  • Installation of temporary shoring
  • Soil nail and wall design parameters
  • Survey monitoring to ensure adequate shoring and to prevent effects on neighboring properties

For more information on this project, visit