Working close to existing structures? Constrained sites? Concerned about vibrations from pile driving? These are all common reasons why project teams specify drilled micropiles for foundation support. Project teams also deal with the reality that drilled micropiles are often expensive and slow to install. Although drilled micropiles may be unavoidable at some sites, many other projects can benefit from a cost-effective and rapid alternative – Ductile Iron Piles.
DUCTILE IRON PILES, A DRILLED MICROPILE ALTERNATIVE
The Ductile Iron Pile (DIP) system, designed and installed by Helical Drilling, is a unique hybrid technology offering advantages of both driven piles and drilled micropiles. The system is installed using an excavator-mounted, medium-sized percussion hammer to rapidly advance the pile using high-frequency percussive energy. The high frequency drive energy produces minimal vibrations, allowing the system to effectively work immediately adjacent to existing buildings. Field monitoring data shows vibration levels (PPV) at a distance of only 2 feet are typically below 0.5 in/second. The Ductile Iron Pile system often provides capacities up to 100 tons in compression through end-bearing or a frictional bond zone like micropiles. Tension resistance up to 60 tons is also common with the friction bond zone. The modular nature of the piles and medium-sized installation equipment allows the system to gain access to tight sites. In addition, the Plug and Drive connection system results in rapid installations with production rates of 400 to more than 1,200 linear feet per crew day.
While some projects located in basements (low overhead) or dealing with heavy debris or existing foundation drilling are appropriately directed to drilled micropiles, the Ductile Iron Pile system represents a cost-effective and rapid alternative to many other drilled micropile projects. Experience has shown the Ductile Iron Pile alternative to drilled micropiles often cuts the foundation cost and installation time in half or more.
RECENT DUCTILE IRON PILE INSTALLATIONS
Johnson & Wales University – Friction DIP Installation
Peterborough Street Apartments – End-Bearing DIP Installation
