THE AHMS HYBRID MARINE PILE SYSTEM
How Our Torque-Installed Helical Foundation Compares with Conventional Prestressed Driven Concrete Piles
Prestressed precast driven piles are a conventional competing foundation method used throughout the marine industry. AHMS does not install driven precast piles. Our system takes a different approach: we install a torque-monitored helical foundation first and then construct the reinforced marine pile in place. The comparison below explains why this can offer practical advantages for docks, boat lifts, marina structures, moorings, and other coastal work.
AHMS Hybrid Helical / Cast-in-Place Pile
AHMS first installs a 1.75-inch square-shaft helical foundation into the seabed. Installation torque is monitored as the shaft advances and extensions can be added to reach suitable founding conditions. The structural marine pile is then formed in place around the helical foundation using a 15-inch UHMW casing, concrete, and an FRP reinforcing cage.
Prestressed Precast Concrete Pile
A factory-cast concrete pile contains high-strength prestressing strands. The strands place the concrete into compression, helping it resist handling, bending, and impact-driving stresses. The finished pile is driven into the seabed with an impact or vibratory hammer. Foundation resistance develops from shaft/skin friction along the pile and end bearing at the tip.
Why AHMS Uses the Hybrid Helical / Cast-in-Place System
• Measured installation feedback: Helical installation torque provides real-time information about soil resistance as the foundation is advanced. Capacity correlations require proper engineering and system qualification, but torque is a valuable field quality-control tool.
• Adaptability to changing soil: If resistance drops after penetrating a dense intermediate layer, additional shaft extensions can be installed until an acceptable founding condition is reached rather than relying only on a predetermined pile length.
• No impact driving of the concrete pile: The concrete portion of the AHMS pile is cast in its final position. It does not have to survive repeated hammer blows during installation.
• Low vibration and reduced installation disturbance: Rotational helical installation generally produces much less vibration than impact driving, which can be valuable around existing docks, seawalls, buildings, utilities, and sensitive marina operations.
• Marine corrosion strategy: The finished pile uses an FRP reinforcing cage rather than conventional reinforcing steel, together with a permanent polymer casing. This removes the normal rebar-corrosion mechanism from the reinforced concrete portion of the pile.
• Modular island logistics: Long finished precast piles, large pile-driving hammers, and specialized pile-driving barges can be difficult to transport and mobilize. AHMS uses modular shaft extensions and forms the final pile at the project site.
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