Segmental retaining walls deliver both practical land use benefits and breathtaking aesthetics. Nowhere is that more apparent than the beautiful, tiered segmental retaining walls that surround the Vista and The Row at Wellington Heights, just outside of Dale City, CA.
The hilltop master planned community features stunning views of Lake Merced, the Pacific Ocean, and the Farallon Islands. Located near Interstate 280 and the Dale City BART station, the two neighborhoods are within 15 miles of both downtown San Francisco and San Francisco International Airport, and are just minutes from San Francisco State University.
The Wellington Heights master-plan community includes two distinct styles of homes —The Vista and The Row—featuring desirable price points and design features such as open floor plans, spacious kitchens, large game rooms and attached secure garages with interior access. The three-story homes at The Row range in size from 2,209 to 2,781 square feet, with up to four bedrooms, and three-and-a-half baths. The Vista features two- and three-story townhome-style condominiums ranging in size from 1,234 to 2,052 square feet, with up to five bedrooms and four baths.
SRW triumphs over a tricky site
Some 40,000 square feet of retaining wall surround the carefully planned residential community. CMHA-member Basalite Concrete Products supplied its Geowall Max units.
With over 50 years in the business, Basalite, a strong supporter of CMHA, manufactures and distributes not only retaining wall units, but also concrete pavers, concrete masonry units, dry mix and related accessories throughout the western United States and Canada. Based in California, Basalite has three manufacturing locations in the Golden State, along with facilities in Colorado, Nevada, Idaho, Washington, along with British Columbia and Alberta, Canada.
The Geowall Series by Basalite features an open core design and high strength fiberglass pin connection system. Geowall Max is the largest block of the series. It is popular for roadway, residential and commercial projects. The Geowall Max and Geowall Pro units can be used by themselves for gravity walls, or in combination with geogrid for taller mechanically stabilized earth walls (MSE). The Max and Pro units are available in a variety of face styles. In the case of the Wellington project, geogrid was an integral part of the design.
“The Wellington project really shows off both the mechanical and aesthetic benefits of Basalite’s GeoWall Max line, Victor Venuta, Basalite’s Technical Representative, said. “The wall met numerous design challenges and really sets off the whole development.”
Perched on the edge of a cliff, the project was not without its challenges, according to Stuart Campbell of BC McCosker. “We were literally working one foot from the edge of a sheer cliff,” said Stuart Campbell, who managed the installation for BC, the contractor who built the walls.
Multiple tiers add to the aesthetic
While a single, taller wall (instead of the tiered system) was considered, “the tiers provided a more aesthetically pleasing option than a large monolithic structure,” said Campbell.
ENGEO Inc. of San Ramon, and Stevens, Ferrone & Bailey, Concord, CA, handled the engineering on the project, designing a robust geogrid system to ensure that the tiered walls perform as intended.