NYCT's 207th St Yard Floodwall-Paper

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The NYCT 207th Street Yard Marine Floodwall is part of the post–Superstorm Sandy effort to protect New York City Transit infrastructure from future flooding. The 1,500-foot wall along the Harlem River was designed to withstand a 500-year storm event.<br /><br />After contract award, Walsh Construction Company II and Mueser Rutledge Consulting Engineers proposed a value-engineering redesign. The original system of 937 W40x235 H-piles with PS27.5 sheets was replaced by 279 54-inch steel pipe piles connected with welded PZ35 sheet piles. The revised system met the project’s material and coating requirements while reducing potential interference from underwater obstructions and limiting the number of piles driven near existing structures. The redesign produced $7.8 million in shared savings, reducing the total cost from $31.62 million to $23.82 million.<br /><br />To address challenging site conditions and improve safety and productivity, the team developed a floating “Tomahawk” template, called the Floating T, and pile-alignment devices including the Flying V and a rolling Interlock Pocket System. These methods improved installation rates from an initial estimate of 1–2 piles per day to 5–6, and reduced crane-barge relocations. Pile driving was expected to finish two months ahead of schedule.<br /><br />Because the new wall was close to the existing seawall, automated survey equipment tracked settlement, while vibration monitors checked construction impacts. The project emphasized quality controls for alignment, plumbness, coatings, and pile interlocks. The pile-driving crew recorded no safety incidents. Overall, the project demonstrates how redesign, planning, and on-site innovation can improve cost, schedule, safety, and construction quality without compromising flood protection.

Keywords

NYCT 207th Street Yard

Marine Floodwall

Superstorm Sandy

Harlem River

flood protection

value engineering

steel pipe piles

pile driving

construction innovation

shared savings