Project teams frequently work on soft soil sites, requiring deep foundation support. Often times, these sites are bordered by adjacent vibration-sensitive structures. The generation of high vibrations created by most driven pile systems cause project teams to reject the use of driven piles on urban projects with nearby adjacent structures and opt for slower and more expensive, low vibration methods like drilled shafts or micropiles. However, DuroTerra’s regional partners are successfully installing Ductile Iron Piles, a unique driven pile system that generates significantly reduced vibration levels when compared with traditional driven piles while still delivering moderate to high capacity foundation support.
Unlike traditional pile installations using large hammers (drop, air/stream, diesel, etc) that generate high amplitude and low frequency vibrations that travel long distances and can greatly exceed vibration limits, DuroTerra’s Ductile Iron Pile System, the optimal micropile alternative, is installed using an excavator-mounted, medium-sized percussion hammer to advance the pile using high-frequency percussive energy. The high frequency vibration waves during pile installation are significantly lower amplitude compared with traditional driven pile operation. Additionally, the high frequency waves dissipate rapidly with distance from the energy source. The end result is a driven pile system that results in minimal levels of vibration during driving.
Vibration measurements show peak particle velocities well below 2 inches per second at distances of less than one foot from installations with frequency levels typically ranging from 20 Hz to greater than 100 Hz. Measurements of vibration levels during Ductile Iron Pile installation typically range from 0.1 to 0.3 in/sec at distances as close as 2 feet from the installation location depending on soil conditions and pile sizes. These low vibration levels further diminish rapidly with distance from the energy source and are less than 0.1 in/sec at distances of 10 feet from installation based on field measurements.
Ductile Iron Vibration Levels vs Frequency
Take a few minutes to read a project summary showcasing how Ductile Iron Piles, a cost-effective micropile alternative, were used to provide deep foundation support on a site where vibrations were a big concern.