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Solmax recently received the Advanced Textiles Association’s (ATA) International 2024 Achievement Award of Excellence in the Geosynthetics Project – Site Development category for its Yerba Buena Island (YBI) redevelopment project.
Yerba Buena Island (YBI) is a natural island located in the San Francisco Bay. It’s adjoining island, Treasure, is a man-made island that was built in the 1930s. The city of San Francisco and private developers have been planning a $1.5 billion redevelopment of the two islands, which spans 405 acres. The project embraces the quintessential California lifestyle, incorporating homes, public transportation, parks and open spaces, public art, hotels, and restaurants.
The first phase of the project included building a residential condominium on the northeast-central side of YBI between I-80 and Macalla Road. Construction of the multimillion-dollar complex required infrastructure improvements and upgrades to Macalla Road.
During a heavy precipitation event in Fall 2021, stormwater runoff built up within the gravel encasement surrounding the stormwater piping beneath Macalla Road. The stormwater buildup increased pore pressure below the subsurface, resulting in slope failure on the north side of the road. The heavily eroded slope was 67°, 120 feet long, and consisted of silty sandy soil. Adding complexity to the project, a sanitary sewer line and a primary natural gas line were on the slope face.
ENGEO, a geotechnical engineering firm, contacted Solmax to help engineer a solution providing slope stability and erosion protection of the slope while also protecting the underground utilities. Incorporating the design factor of safety (FoS) for static and seismic conditions, it was determined that the PROPEX Armormax system was the best solution. PROPEX Armormax is a solution for surficial slope stabilization that provides vegetated reinforcement, improves the factor of safety, and significantly reduces the probability of failure.
The system is composed of Engineered Earth Anchors that are designed and tested for compatibility and performance with PROPEX Pyramat High-Performance Turf Reinforcement Mat (HPTRM) to increase slope stability. Six-foot, B3 anchors on a 5’ x 4’ spacing with 1,200 pounds of anchor pullout capacity met the design FoS.
Upon approval from all environmental agencies and the city of San Francisco, the slope was rebuilt and PROPEX Armormax was installed in 2022 by Selby’s Seed & Erosion Control. Due to the steepness of the slope, installers used harnesses and ropes tethered at the crest of slope for safety. After installation, the HPTRM was sprayed with a bonded fiber matrix containing native seed to establish vegetation. Due to the construction techniques used, no additional construction equipment was required, and no road closures or traffic control were required for Macalla Road.
ENGEO was pleased with the success of this project and has identified additional PROPEX Armormax installations on the Treasure Island/Yerba Buena Island Development Project. The installation was successful, and PROPEX Armormax has been installed on three additional sites on Yerba Buena between 2022 and 2023.
Project Details
Fabric 1
Propex Armormax
Producer/Manufacturer: Solmax International Inc.
Primary Use: Main Fabric
Engineer Company 1
Engeo
Project Manager Company
Engeo
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To explore all the 2024 International Achievement Awards Winners entries and read detailed project descriptions , click here. You can also see the IAA Geosynthetic Projects winners here.