STELCOR Supports a Complex Development Site in Brooklyn’s Gowanus Neighborhood

OVERVIEW:

Located in Brooklyn’s Gowanus neighborhood, 526 Baltic Street is a 11-story new-construction development. East Coast Bulkheading, a certified STELCOR installer, performed the deep foundation installation  

PROJECT TEAM:

Structural Engineer: Structural Engineering Technologies

Geotechnical Engineer: KnF Services Corp 

Installation Contractor: East Coast Bulkheading 

CHALLENGES:

Like many sites in the Gowanus neighborhood, this project presented a complex combination of contaminated soils, limited access, and nearby structures. There was limited space to mobilize large rigs, and vibrations posed a risk to nearby buildings. Any soil removed, or spoils generated from pressure grouting, would be costly to handle and remove due to environmental requirements. These constraints drove the need for a deep foundation that could be installed with compact equipment, no spoils, and minimal disruption—without sacrificing schedule or budget. 

SOLUTION:

IDEAL was introduced to this project by the foundation contractor to evaluate a value-engineered solution to the original foundation design, an 80-foot, 9 5/8” micropile. STELCOR Drilled-In Displacement Piles were presented as an alternate 100-ton pile that could significantly reduce the installation schedule and reduce overall foundation cost.

The installation crew achieved an average installation rate of 8–9 STELCOR piles per day, nearly triple the estimated rate of the originally specified micropile. In addition to cutting the foundation schedule by about 23 days, STELCOR presented further savings and peace of mind by eliminating the cost and complexity of treating and managing contaminated spoils. The vibrationless installation and use of an excavator were also beneficial due to the limited space on site and neighboring buildings.

DESIGN LOADS:
Compression: 100 tons
Tension: 25 tons
Lateral: 4 tons

PILE DETAILS: 
Type: STELCOR 1600 
Nominal Grout Diameter: 16 inches 
Steel Core: 5-1/2" O.D. 0.361" W.T. 
Quantity: 112 piles 
Length: 75 feet 

SOIL PROFILE: 
 The soil profile consisted of approximately 12 feet of silty sand fill with trace gravel, underlain by a soft to stiff organic silt layer. Beneath that, a more competent sand and silt stratum with variable clay content provided suitable bearing conditions. Groundwater was encountered between 6 and 7 feet below grade.