Boston Waterfront Redevelopment: Re-Use of Existing Pier Piles to House Future Generations-PPT Presentation

PPT Presentation

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The Boston Waterfront Redevelopment project evaluated whether existing piles beneath Pier One in East Boston could support future residential buildings. The 5.4-acre pier, built in 1954, was founded on concrete-filled steel pipe piles extending roughly 95–135 feet below the deck into glacial till and weathered bedrock. Subsurface conditions also include soft fill and thick deposits of Boston Blue Clay.<br /><br />Before reuse, piles were inspected and repaired. Severe corrosion and holes were found mainly in the splash and mean-low-water zones. Repairs involved installing 18-inch steel sleeves around affected sections and grouting the annulus, providing an allowable structural capacity of 300 kips per pile.<br /><br />A two-phase testing program combined dynamic, Statnamic, and sonic echo testing. Phase 1 tested two piles and indicated that reuse was feasible, though low pile movement suggested the full soil and rock resistance had not been mobilized. Phase 2 tested ten additional piles. Sonic echo testing found no significant defects; nine piles showed toe reflections consistent with their recorded lengths.<br /><br />In Phase 2, allowable dynamic test capacities ranged from 268 to 376 kips. Four of ten piles reached the 300-kip design load, while six fell short; several were close to their estimated ultimate capacity. Pile movement remained below 0.3 inches, indicating that the tests likely did not fully mobilize the soil and weathered-rock resistance. Load-transfer results confirmed that the lower pile sections were embedded in glacial till and weathered bedrock beneath the clay.<br /><br />The findings supported reuse of the existing piles, subject to structural repair and project-specific evaluation. The authors noted that higher test loads might have demonstrated greater geotechnical capacity, but could also have risked damaging the piles.

Keywords

Boston Waterfront Redevelopment

Pier One

East Boston

pile foundations

concrete-filled steel pipe piles

structural repair

dynamic testing

Statnamic testing

sonic echo testing

glacial till