Liquefaction analysis: CPT versus SPT results at JFK airport

The design and construction of the new JetBlue 26-gate Terminal Facility at JFK Airport in New York City, USA was a complex and interesting endeavor for the Geotechnical Engineers at DMJM Harris. Once operational, the 635,000 sq. ft. facility will operate up to 250 daily flights; an estimated 20 million passengers a year. The new Jet Blue Terminal 5 incorporates the historical TWA Terminal, designed by Eero Saarinen in 1962. The main portion of this structure is being refurbished and incorporated into the new terminal. There were many challenging features to the design of this Project; including marrying the existing historical structure to the new terminal, preventing cross contamination in the aquifers below the site and achieving a design which will perform under seismic conditions. The challenge of the evaluation of the soil under seismic conditions is discussed herein. Liquefaction under seismic conditions at JFK Airport can be a key factor to foundation design and selection. Our investigation of the site incorporated the use of both Standard Penetration Testing (SPT) and Cone Penetration Testing (CPT) to closely identify the areas subject to liquefaction risk. A correlation between the results of both the analyses was established. This enabled us to determine the thickness of liquefiable zone and develop a cost effective design solution that will perform successfully should a seismic hazard occur in the future. The methodology utilized and the correlation observed will be presented in the paper.