Eli Gottleib
Managing Principal & NY Office Director
Thornton Tomasetti, New York City

“Vessel,” designed by Thomas Heatherwick, is the centerpiece of the Public Square and Gardens at Hudson Yards. Both sculpture and interactive structure, the 46-meter-tall Vessel is an expanding lattice of 154 flights of stairs and 80 landings. The concise 15-meter diameter base minimizes the impact to the landscape and invites a more personal experience, while the expanding width, which reaches 46 meters at the top, offers a broader relationship with the surrounding park and buildings.

The structural framework supporting the mile of ramps and landings was developed with inspiration drawn from shipbuilding and bridge design. The thin-walled, steel structure evolved with attention given to aesthetics, structural integrity, constructability and economy. From the outset, consideration was given to not only the details which would influence the plate assembly, weld sequence and fabrication, but also to the overall logistics of transportation, site connections and erection sequence.

Given the very light weight and inherent cantilever of the spiraling staircases human induced footfall vibrations were a significant design constraint. Consideration was given to vibrations and occupant comfort both as a stair and a viewing platform, significantly increasing the sensitivity of the issues. The design includes a set of tuned TMDs to mitigate vibrations and expand potential uses and occupancy. Structural analysis, detailing, development of the vibration criteria, the vibration studies led to the final implementation of the supplemental damping for the structure.