Deep Foundation Support for the Iconic New York Wheel-Paper

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The paper describes the design, testing, and construction of deep foundations for the 630-foot New York Wheel on Staten Island. Challenging subsurface conditions included loose fill, thick soft former river-bottom deposits, liquefaction-susceptible sands, and highly variable weathered Serpentinite bedrock. Although liquefaction was possible, analysis predicted negligible lateral spreading.<br /><br />The Wheel’s four reinforced-concrete foundation caps are supported by groups of 24 drilled shafts, designed for substantial compression, uplift, and lateral loads. Each shaft extends through weak and potentially liquefiable soils into a bedrock socket. Design accounted for soil strength loss during seismic loading, closely spaced shaft group effects, and a strict one-inch service deflection limit.<br /><br />Four test shafts were installed: two underwent Osterberg-cell (O-cell) axial load tests, and two underwent lateral load tests. O-cell results showed that ultimate socket side resistance was not fully mobilized, so load-transfer behavior was used to estimate ultimate values. Resistance varied with bedrock condition: more weathered upper rock behaved like an intermediate soil material, while stronger lower rock behaved more like competent rock. Side resistance generally increased with rock quality. Some common design methods were conservative, while others produced variable or less-conservative estimates.<br /><br />Lateral testing and calibrated analysis indicated that production shafts could meet service-load demands while staying within the specified deflection limit, including consideration of liquefaction, cyclic softening, corrosion, and group effects.<br /><br />Construction controls emphasized verifying socket geometry and cleanliness, monitoring drilling resistance as an indicator of rock conditions, and limiting the time between socket completion and concrete placement. Test shafts were incorporated into the permanent foundation. The project demonstrates the value of full-scale load testing and close quality assurance when designing drilled shafts in variable rock and seismic-prone soils.

Keywords

deep foundations

drilled shafts

New York Wheel

Staten Island

liquefaction

Osterberg-cell load test

bedrock socket

foundation design

lateral load test

seismic loading