309 East 94th Street

1 / 2
2 / 2

Underpinning value-engineered and constructed the deep foundations to support a nine-story commercial life sciences building on Manhattan’s Upper East Side. The 13,000 square foot site is bordered by old residential buildings on shallow foundations.

Historically occupied by wetland marshes and creeks, the subsurface consists of uncontrolled fill over soft soils and silts, making nearby structures especially prone to construction-induced settlements. Underpinning teamed with consulting engineering firm Magnum Geo-Solutions to value engineer the bid design’s specified auger-cast-in-place pile system. The rotary-driven pipe pile was selected to improve cost and schedule while minimizing ground vibrations and maximizing usable space on a small project site.

The rotary-driven pipe pile is a full-displacement pile that does not produce any drill spoils. It consists of a 12.75-inch diameter casing with a sacrificial drill tip and is installed by rotation using crowd and torque instead of by conventional piledriving methods. The casing is filled with concrete after installation.

Did you know?
A total of 320 each production piles were installed 120 feet below ground surface to achieve a 75-ton allowable pile capacity.