Click Here to see this case study featured in Helical Pile World
- Location: Brooklyn, NY
- Certified Installer: Foundation Stabilizers, Inc (FSI)
- Engineer of Record (EOR): Petracca Design and Engineering, P.C.
- Helical Pile Specifications:
– 804 MacLean Power Systems (MPS) Helical Piles
– P35H (3.50″ x 0.300″ Round Corner) Lead w/ 10″, 12″, 14″ Dia. Helices on a 7′ Shaft, a P35H Follower w/ 14″, 14″ Helices, & P35H Extensions Encased in an 8″ Dia. Grout Column
– Average Depth of Helical Piles: 32′
– Average Installation Torque of Helical Piles: 9833 ft-lbs
- Ultimate Load(s):
– 100 kips (Compression)
The current Kristal Auto Mall site is a former Marina, which consisted of a small building and a large parking lot for the adjacent marine. The challenge at this site was simple: build a multistory car dealership on weak soils that also encountered tidal influence. After many back and forth conversations, Petracca Design and Engineering chose to use a P35H lead with a 10”, 12”, 14” helix configuration, a P35H 14”, 14” follower, P35H extensions encompassed by an 8” diameter grout column in the upper 18ft. The 8” grout column served to stabilize the pile laterally, while the friction from the grout column increased the compression capacity of the helical pile. Foundation Stabilizers Inc. installed a total of 1076 piles, but not without some changes along the way. Soil testing indicated that this particular site was susceptible to increased corrosion due to the high resistivity values found in the soil combined with the tidal action of Jamaica Bay. In order to combat the increased corrosion capacity, cathodic protection was utilized. Cathodic protection uses a sacrificial metal, usually zinc to extend the life of the pile by corroding the sacrificial metal instead of the pile.
Aerial view of the Southern part of the site
Wires connecting the pile caps to the anode for the cathodic protection