OVERVIEW:
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.
CHALLENGE:
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.
SOLUTION:
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.
INSTALLER:
EMC Inc.
GEOTECHNICAL ENGINEER:
Soil Mechanics
LOADS:
200 kips ultimate
PILE DETAIL:
STELCOR 1200
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’
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