Hospital for Special Surgery – The Kellen Tower

New York, NY

Tishman Construction Corporation

Contract Value:
$18 Million

Project Dates:
January 2022 - October 2023

  • 360 CY of 10,000 PSI concrete with Hycrete X-1000 waterproofing and corrosion inhibiting admixture
  • 18” diameter drilled caissons with 28 FT rock sockets
  • 150,000 LBS of rebar
  • Line drilled up to 8.5’ deep and chopped 71 CY of granite bedrock
  • Average footing width varied from 3 FT to 6 FT and depths of up to 15’ below existing grade


Posillico worked for Tishman Construction and Hospital for Special Surgery adding a building to their existing facility, which spans across FDR Drive. Posillico handled the foundations for the super structure for the new Kellen Tower standing over FDR Drive. Scopes included soil excavation, SOE with soldier piles and lagging, rock excavation, rebar installation and concrete placement. Drilled foundation elements: caissons and rock anchors (vertical and battered).


There were stipulated NYCDOT lane closures restricting Posillico to work in 5-6 hour windows which caused signification reductions of shift duration and caused work to be performed at night. This also led to logistical issues with deliveries. Working along the East River also made this job complex as Posillico had to adjust work to tidal movements which restricted work time even more as tides did not line up with DOT restrictions. Additional challenges included delays due to permits, restricted real estate to maneuver the equipment and hazards tied to ongoing traffic.


Posillico made adjustments in shifts and coordinated with client, vendors and subs on site to accommodate scheduling restrictions which required diligent communication and planning.  Past experiences and lessons learned assisted Posillico with MPT and lane closures on the FDR. Scheduled deliveries of material we sent in bags instead of truckloads of fill, in response to the lane closure limitations. Posillico worked with their valuable engineers and worked out a way out a way to avoid using a crane for bridge demo and used an excavator instead to avoid NYCDOT & NYCDOB permits for selection of specialty equipment.