Traditional driven piles are often associated with high vibration installations. As Jerry Lee Lewis might have sung “there’s a whole lotta shakin’ going on.” But that’s not the case with TRM’s Ductile Iron Piles – a low vibration driven pile system. Instead, it’s more like the Beach Boys singing “Good…good….good…Good Vibrations.” That’s right – Ductile Iron Piles are a bit of a paradox in the driven pile world. The system provides many of the benefits of a driven pile including speed and cost-savings AND is a low vibration option that is often selected as an alternative to micropiles or helical piles on sites where vibrations are a concern.
How is that possible? Ductile Iron Piles are installed with an excavator-mounted hydraulic breaker hammer (i.e. demolition hammer) that delivers direct percussion energy (not vibratory) to the pile head. While the energy per blow is much lower than a traditional diesel hammer, the hammer strikes at a much higher frequency to deliver the driving energy. The typical impact frequency ranges from 300 to 600 blows per minute – that’s 5 to 10 blows per second! But unlike a vibratory hammer used for some pile installations, this energy remains direct impact energy. The combination of the lower energy/blow and the higher frequency impact results in a system that rapidly drives the pile with minimal vibrations.
Substantial vibration data has been collected at various project sites to verify acceptable levels and also provides project teams with information to assess the feasibility of using a Ductile Iron Pile solution. These data are summarized in the Tech Brief on Ductile Iron Pile Vibration and Sound. As shown, the measured peak particle velocities (PPV) are typically between 0.25 ips and 1.0 ips at distances of only a few feet from installation.
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