Transforming the former U.S. Navy property into a mixed-use development encountered several challenges including complex subsurface conditions, former land uses and improvements, multiple stakeholders, and sensitivity of adjacent improvements.
The Alameda Landing Redevelopment project sits on approximately 80 acres of marshland and tidal flats that were reclaimed with hydraulic fill. Reclamation and development of the site began in the early 1900s. Over the last 100 years, the site has been used by the Tacoma Beer Company, Golden State Miners Iron Works, San Francisco Bay Airdrome, and, most recently, U.S. Navy Fleet Industrial Supply Center.
The site is bound by settlement-sensitive improvements including buildings, tunnels, roadways, and utilities (above and below ground that could not be adversely impacted by the proposed development.) Redevelopment involved construction of residential office, and retail structures, and new public infrastructure (roadways and underground utilities). In addition, existing adjacent roadways were widened and rehabilitated as part of the project due to the increased traffic and condition of the roadways.
The complicated subsurface conditions, former land uses and improvements, and settlement sensitive adjacent improvements presented multiple challenges. The challenges included undocumented liquefiable hydraulic fill and compressible marine clay (Bay Mud) that varies in thickness. These challenges were further complicated by the necessity to raise the site grades by several feet to meet projected future sea-level rise. In addition, the presence of shallow groundwater and environmental impacted soil and groundwater were also present, which necessitated additional considerations and interaction with local, state, and federal regulators. Along with these issues, the project involved a great deal of coordination and interaction with the project team and multiple stakeholders. These stakeholders included local, state, and federal regulators, adjacent property owners, multiple contractors, architects, structural engineers, and multiple developers and tenants. The schedule, construction phasing, cost-constraints, and specific performance criteria of each developer and tenant required precision in phasing of the construction and ground improvement operations.
Langan evaluated and provided recommendations for multiple foundation types (shallow and deep foundations) and ground improvement techniques to meet the project goals. Ground improvement techniques included pre-consolidation using soil surcharges and pre-fabricated vertical drains, densification, reinforced earth pads, and lightweight fills.
Answer Provided by Haze M. Rodgers, PE, GE, Senior Project Engineer
Haze has more than 12 years of experience providing geotechnical consulting services, including subsurface exploration, laboratory testing, and construction observation. During design, he provides soil structure interaction evaluations (static and dynamic), ground improvement evaluations, slope stability, and foundation designs. His projects include commercial and residential structures, deep excavations, infrastructure (roadways and utilities), marine and waterfront developments (piers, wharves, and harbors), seismic strengthening, and landslide stabilizations.