DuroTerra Dialogue: Don’t get hung up on helical piles
Don’t get hung up on helical piles!
Helical piles are used for underpinning of existing structures and for new construction of boardwalks and lightly loaded buildings. Like any piling system, there can be limitations that impact the overall benefit. We often hear these concerns from design professionals and contractors on projects utilizing or considering helical piles.
- Are you concerned about not achieving the torque requirements?
- What about cost overruns when piles must extend deeper to generate the required capacity?
- Will the helical piles “torque out” before getting through an undocumented fill or “spin out” in soft soils over a hard layer leaving you with questions about capacity?
- Do you need greater pile capacity to optimize your foundations but not sure if you can get there with helical piles in your soil conditions?
A Helical Pile Alternative
Ductile Iron Piles have become a go-to alternative for helical pile projects to provide a reliable, higher-capacity alternative for new construction, building additions, and interior renovations. The modular, low-vibration Ductile Iron Pile system is installed using an excavator-mounted medium-sized percussion hammer to drive the pile using high-frequency percussive energy. This method produces minimal vibrations, allowing the system to effectively work immediately adjacent to or inside existing buildings. The modular piles and medium-sized equipment allow the system to be easily used on tight sites. In addition, TRM’s Plug and Drive connection system results in rapid installations with production rates of 400 to more than 1,200 linear feet per crew day.
Ductile Iron Piles offer compression capacities of 25 to more than 100 tons by either end-bearing on competent soil/rock or by creating a grouted friction bond zone like a micropile. The greater capacity often results in fewer piles and a more cost-effective foundation. This versatility in developing geotechnical resistance provides confidence that you will develop high capacities in a variety of ground conditions and lowers your risk for change orders resulting from unexpected helical pile performance.
If you are considering helical piles on your project, reach out to us for a feasibility assessment to know your options.
Relevant projects
Ductile Iron Piles save time and money by replacing helical piles
After a failing helical pile load test, the project team was scrambling to find an alternative foundation solution to avoid significant cost and schedule impacts to the piling scope. The expansion of the existing substation included support of isolated, small foundations and numerous larger mat foundations subjected to compression, tension, and lateral loads. Peterson Contractors, Inc. proposed a combined solution using Geopier® ground improvement for lightly loaded foundations and Ductile Iron Piles to support larger mats. The piles were driven approximately 45 to 50 feet through the soft clay to develop frictional capacity in the medium-dense sand below. Full-scale load testing confirmed design capacities of 67 kips (compression) and 37 kips (tension). A total of 94 friction piles were installed to 65 feet in less than 2 weeks. The combined solution of Ductile Iron Piles and ground improvement prevented significant delays and change orders due to foundation cost overruns.
Over 2,700 LF of Ductile Iron Piles installed in 2 days
Schedule and responsiveness play an important role in meeting project deadlines – especially when winter is bearing down on your foundation work in Upstate New York. Renovations and improvements to the existing General Electric (GE) facility in Schenectady, New York specified helical piles for foundation support. The project team was concerned about the delay risk associated with problems penetrating the fill and achieving the required capacity in poor soil conditions. An alternative approach using friction Ductile Iron Piles provided a cost-effective solution to easily drive through the fill and develop frictional capacity through grout-to-ground bonding. Design, mobilization, testing, installation and demobilization were all completed within only 2 weeks after project award. A total of 55 production piles were installed to depths of about 50 feet in only 2 working days, well ahead of the winter weather.
