The foundation of the 100-year-old Malt House building had to be underpinned in order to allow 5 additional floors to be added to it. This building is in the Manhattanville Factory District – New York’s most important master-planned economic and urban revitalization project. The piles had to be installed in a basement and vibration and spoils were a concern.
One challenge with installing in the existing basement was low headroom. However, the most significant challenge faced during installation was the presence of a boulder and cobble layer which ranged from 8’ to 16’ deep.
The vibrationless installation of Stelcor Drilled-In Displacement Micropiles met the vibration concern. The low headroom was addressed by installing the piles with a small excavator and using a high-flow skid steer to power the drive head. The installer, EMC, Inc. stated that every one of the 82 pile locations had to be augered to 18’ with a 16” rock auger to penetrate the boulder/cobble layer. While these conditions made for a very difficult installation, Stelcor DDM was still the most cost-effective piling method for this project.
200 kips ultimate
14” tip or drive plate
12” corrugated grout column
9” solid grout column
8” reverse auger
5.5” steel core
.361 wall thickness 80 ksi
SOILS + EMBEDMENT DEPTH:
Difficult soils with boulders and cobbles. Installed to depths of 50-68’