Rotary-Driven Pipe Piles as a Solution in a Congested Dense Urban Construction Site-PPT Presentation

PPT Presentation

Pdf Summary

The project involved constructing an 8-to-9-story building on Manhattan’s Upper East Side, where variable soils, nearby buildings, and a constrained urban site made conventional drilled or auger-cast piles costly and difficult to install. The original concept called for 190–250 piles, 18–30 inches in diameter and 115–150 feet long.<br /><br />The team selected a contractor-designed alternative: 320 rotary-driven, 12.75-inch-diameter steel pipe piles, approximately 120 feet long, with a target compression capacity of 75 tons each. Each pile used a closed-ended steel casing and sacrificial helical drill tip, installed by rotation and crowd. The method required no drilling fluid or spoils and generated relatively little noise and vibration. After review, the piles were approved by New York City’s Department of Buildings, subject to successful load testing.<br /><br />An index-pile program included installation monitoring, re-torque measurements, and compression, uplift, and lateral load tests. Re-torque results did not establish a clear relationship between resistance and pile setup. Compression tests showed that end-bearing capacity could not be relied upon; measured side shear did not fully mobilize the ultimate values used in design.<br /><br />The presentation concludes that rotary-driven piles were a successful, fast, and cost-effective value-engineering solution that avoided impacts to adjacent structures. It also notes that pile setup warrants further study, direct torque measurement during installation would have been useful, and variable soil conditions and pile performance mean some differential settlement should be expected.

Keywords

Manhattan Upper East Side

8-to-9-story building

rotary-driven steel pipe piles

variable soil conditions

constrained urban site

value engineering solution

load testing

compression capacity

adjacent structures

differential settlement