SoMi Affordable Housing Development
Bioretention & Steep Slope Stabilization
Commercial Project | Hayward, CA
SoMi is a new collection of 23 modern multi-family buildings with 189 condominium and townhome units located within walking distance of the South Hayward BART station. When complete, the 12-acre, $105 million affordable housing development by Homes Built for America will also include more than 10,000 square feet of ground-floor commercial space, an urban park, and a dog park. CalWalls completed a multi-phase project for the community involving steep slope stabilization and bioretention systems.
Our team reinforced an entire hillside with a series of four expansive retaining walls. The standard approach would have been massive excavation and grading of the site in advance to establish a wide foundation clearance, then significant slope reconstruction to build a series of terraces from the bottom up.
Instead, GS2 block technology allowed construction to begin at the top of the hill and work down. This approach was more efficient and less disruptive, requiring about one third of the excavation, backfill, and time expected for a project of this size and type. The first three walls were built on reticular piles, and the bottom wall was built on helical barrel construction. Each level incorporates efficient drainage and a concrete swale behind the top terrace to direct water runoff away from the structure.
CalWalls also constructed two substantial bioswale structures adjacent to a large hill with a natural spring. This bioretention system was designed to capture, filter, and manage stormwater flow to protect structures and waterways. Built with GS2 technology, the massive 12-to-14-foot walls are only partially visible after the addition of biofilter material. These retaining walls also provide soil retention and foundation stabilization for nearby housing structures.
An additional 24,000 square feet of retaining walls were constructed in the hard, dense hillside soil for the multi-family housing area of the development to provide soil stabilization, expand buildable areas, and establish a community park. Our reticulating helical pile system was essential for making this project possible, while also reducing the need for excavation for cost savings and meeting OSHA compliance.
Services
- Collaboration with landscape architect
- Alternative Wall System Analysis
- Excavation and material off-loading
- Helical Pile & Barrel Drilling
- Retaining Wall Construction
- Bioretention System Construction
- Weekly project reviews with client
Products
- GS2 Block
- Concrete Flowline (CCFL)
- Helical Barrels
- Helical Reticulating Piles
Technology
& Equipment
- Hyundai HX130 LCR Crawler Excavator
- Yanmar SV-100 Crawler Excavator
- Hyundai HX145 LCR Crawler Excavator
- Dangle Drill
- Intelli-Tork Torque Monitoring System
- Bobcat
- SWIS Management (Solid Waste Information System)
- GS2 Block
Dig a Little Deeper
Explore additional project photos to view the exceptional craftsmanship that defines our work, inspire your own retaining wall project, and envision the possibilities for your outdoor space.
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