Project Details

Primary contractor
Port Authority of New York & New Jersey
August 2006
Start Date
December 2010
Completion Date

Building the World Trade Center Memorial Foundation

The WTC Memorial Foundations project (contract WTC 115619.99) was the first contract awarded for the reconstruction of the World Trade Center Twin Towers Site.  The Memorial encompasses nearly four acres of the entire sixteen-acre site and maintains the remnants of the original North and South Tower foundations.

The site located sixty-five feet below street level is bounded by the Freedom Tower Project to the North, the PATH Rail Line station to the south and east, and the original World Trade Center site slurry wall to the west.  The work on the project was performed in close cooperation and coordination with other contractors working around and through the site on the surrounding World Trade Center Complex, the Freedom Tower, and Route 9A.

Construction activities included the drilling and blasting of trenches 15 feet into the Manhattan Schist for the construction of shear wall foundations.  Rock removal was also required for the construction of spread footings, sump and elevator pits, viewing galleries, and plumbing and drainage systems.  Foundations in close proximity to the existing slurry wall and PATH Train, where it was impractical to excavate to sound rock, were constructed utilizing minipiles.

Existing structural elements including high voltage duct banks, vaults, and ramp foundations required pit underpinning prior to excavating.  Uplift anchors were installed eighty feet beneath the bottom of foundation at locations potentially subject to uplift.

Coordination with multiple contracts

Structural steel concrete footings, slabs, and stone walls

Geotechnical instrumentation

Environmental impact mitigation including air, noise and emission controls

Excavation and disposal of contaminated soils