The apartment complex boasts green design features from Runberg Architecture Group including living roofs, an urban farm and an interior courtyard with a landscaped stream, pond and shared “treehouse” lounge for residents. (Copyright Michael Walmsley Photography)
GeoEngineers worked with the project’s environmental consultants to log boreholes during the subsurface drilling investigation. The team discovered the soil was competent and could support the structure on shallow spread or mat foundations.
The team used a conventional soldier pile and tieback wall to support excavation on the north side of the site where a large-diameter storm sewer near the excavation required additional shoring support.
On three sides of the excavation, GeoEngineers recommended soil nail walls to support the excavation.
Stika Vulcan Residential Development
LEED Certified Multifamily in Downtown Seattle
GeoEngineers provided geotechnical services to Vulcan Real Estate for their development of Sitka Apartments in Seattle, Washington. The seven-story mixed-use complex includes 365 apartments, 19 townhomes and 3,300 square feet of retail space.
The project architect, Runberg Architecture Group, designed the complex from the ground up to be environmentally sustainable. Features like electric vehicle charging stations, living (vegetated) roofs, bike storage, an urban farm, wastewater recovery and gray water harvesting have earned the apartment complex a LEED for Home Platinum certification from Leadership in Energy and Environmental Design (LEED). An interior courtyard blends city living with green outdoor spaces complete with a landscaped stream, pond and shared “treehouse” lounge for residents.
As the geotechnical consultant on the project, GeoEngineers’ team investigated and characterized soil and groundwater conditions at the site and provided design recommendations for earthwork, foundation design, temporary shoring, slabs-on-grade and permanent below grade walls. The project has been widely praised for its environmentally sustainable features and received awards from NAIOP and Engineering News-Record.
Approach
- Geotechnical Investigation: GeoEngineers reviewed existing subsurface information for the site and surrounding area to gain a baseline understanding of conditions. The geotechnical team worked with the project’s environmental consultant to log borings and then performed soil analyses at accredited GeoEngineers labs. The team discovered fill material overlaying glacially consolidated soils—favorable conditions for shallow foundations.
- Geotechnical Recommendations: Given the competent soil conditions, GeoEngineers recommended cost effective shallow foundations for the project. The team also recommended using a soil nail system as temporary shoring support for three walls of the excavation, and a soldier pile and tieback wall on the north side of the site where a large-diameter storm sewer near the excavation required additional shoring support. The team also gave geotechnical specifications for slabs-on-grade, earthwork and permanent below-grade walls.
- Construction Observation: Once the project reached construction, GeoEngineers provided construction observation services focusing on shoring and excavation, foundation construction, swale construction, soldier pile removal and hardscape subgrades/backfill.
Results
GeoEngineers’ efficient and professional geotechnical services for Sitka Apartments helped the project team build a unique building full of sustainable features that will benefit the community for decades to come. Since its completion, Sitka Apartments has been hailed for its groundbreaking green design by LEED, NAIOP and Engineering News-Record.
Awards
- NAIOP 2019 Award winner in category of Multi-Family Residential Urban Development of the Year: More than 100 Units
- Best Green Project 2019 from Engineering News Record Northwest
- LEED for Home Platinum certification from Leadership in Energy and Environmental Design (LEED)
