Drilled-In Displacement Piles: Lessons Learned from Case History at JFK Airport in New York-Paper

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The JFK Terminal 4 Headhouse expansion required deep foundations beneath an elevated AirTrain and roadway, with clearance as low as 12 ft, strict vibration limits, and an accelerated schedule. Drilled-in displacement piles (DDPs) were selected over micropiles because site soils suited their installation, and they offered higher anticipated capacity, faster construction, and competitive cost. Their low vibration and minimal spoil production were also advantageous beside an operating airport.<br /><br />Because applicable New York City code and Port Authority specifications did not specifically cover DDPs, the project team worked with the Port Authority to develop tailored design and performance requirements. The project installed 178 piles. Specifications emphasized casing through soft marsh deposits and monitoring of installation torque, grout volume, and pile verticality.<br /><br />Eight sacrificial pre-production tests—compression, tension, and lateral—validated the contractor’s methods and pile performance. Test results showed substantial end-bearing resistance in the underlying glacial sands. Joint analysis of compression and tension tests enabled the design pile length to be reduced by 17%, lowering material use and installation time while meeting performance requirements. Test piles also encountered torque refusal and sometimes failed to reach their target depth, prompting shorter production piles and defined acceptance criteria for toe elevation, torque, and grout volume.<br /><br />Construction experience underscored the importance of reliable quality-control data. A tape-based method for measuring grout volume proved inaccurate and was replaced by a flow meter. Torque data were generally consistent, though recording at intervals shorter than 5 ft was recommended for more detailed analysis.<br /><br />The case demonstrates that DDPs can suit constrained airport projects when supported by early coordination with regulators, project-specific specifications, load testing, and careful monitoring. The testing program both verified capacity and improved construction efficiency.

Keywords

JFK Terminal 4

headhouse expansion

drilled-in displacement piles

deep foundations

airport construction

low vibration

load testing

Port Authority

quality control

glacial sands