A COMPARISON OF DRIVEN STEEL HP-PILES AND AUGERED CAST-IN-PLACE PILES AT A CLOSED LANDFILL ON THE SAN FRANCISCO BAY-PPT Presentation

PPT Presentation

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The Oyster Point redevelopment required building over a former landfill containing refuse and Bay Mud, with bedrock depth varying substantially across the site. Key foundation challenges included supporting building loads, managing long-term settlement and downdrag, reduced lateral pile resistance as soils settle, and corrosion.<br /><br />Settlement estimates varied by development phase: Phase 1 areas showed approximately 2–5 feet, while Phase 2 included areas with up to 6 inches. Estimated downdrag reduced allowable pile capacity by 5–12% in Phase 1 and 3–6% in Phase 2. Testing found that much of the Bay Mud and refuse in the upper 40–50 feet was moderately to severely corrosive, requiring corrosion protection.<br /><br />Foundation solutions were evaluated separately for the two phases. Phase 1 used 14-inch steel H-piles, with lengths of 15–135 feet and measured ultimate capacities of 700–1,400 kips. Phase 2 used 16-inch-diameter augercast-in-place (ACIP) piles, 21–105 feet long, with measured ultimate capacities of 700–1,900 kips. Shallow foundations were also indicated in areas outside the refuse.<br /><br />Pile load testing, including dynamic and static tests, helped assess capacity and inform design. The project illustrates how foundation selection for landfill redevelopment depends on refuse and Bay Mud conditions, bedrock variability, corrosion, settlement effects, construction considerations, and cost.

Keywords

Oyster Point redevelopment

landfill foundation

Bay Mud

pile foundations

settlement

downdrag

corrosion protection

steel H-piles

augercast-in-place piles

pile load testing