The helical pile was invented by Alexander Mitchell, an Irish engineer, as a method to stabilize lighthouses, moorings and other structures that were built on sand and mud. The first helical foundation system was installed in the 1830’s. Originally called a screw-pile, the piles were made of cast or wrought iron and were screwed into the ground. The design and installation method provided more stability in weak soils than traditional straight piers. Helical piles have become an accepted industry solution for a variety of problems, including settlement, vibration restrictive installation, lateral loads, and axial tension applications. In 2007 the ICC-ES approved the AC358 Acceptance Criteria for Helical Foundation Systems and Devices. And in 2009 Helical piles are included within chapter 18 of the International Building Code (IBC) 2009.
Why Choose Helical Piles?
Helical piles can be the solution of choice for a variety of applications due to the ease of installation, immediate loading, and ability to stabilize in a diverse environment.
Helical piles are a segmented, deep foundation system with helix blades that are welded to a central shaft, and a bracket that allows attachment to new or existing structures. Helical piles provide a structural solution in restricted access sites, locations with a high water table and sites with weak surface soils.
Helical Pile Applications
Helical piles and tiebacks can be used in a variety of axial compression, axial tension and/or lateral load applications:
- Slab support
- Basement or retaining wall tie-back
- Remedial underpinning
- Pedestrian bridges
- Sign supports
- Beach front properties
- Machine or equipment foundation for immediate loading with increased capacity Wind and seismic loading applications such as sound walls, billboards and communication towers.
- Foundation use in areas that are sensitive to noise or vibration which would prohibit the installation of push piers.
- Boat mooring – simple, economical mooring for boats. Installed into the harbor bottom through sand and silt until load bearing soil is reached.
- Earth retention and retaining walls
- Lighting and mooring
- Pipeline anchors
Here are five reasons why to use Helical Piles:
1. Immediate Loading
Helical piles are pre-manufactured, and they can be quickly installed with immediate loading. By comparison, establishing a concrete foundation can take several days because that surface has to cure, possibly delaying to the project’s completion.
2. Small Installation Equipment
Helical piles are installed by hydraulic motors, which can be attached to a number of different machines. Installation vehicles commonly include skid-steer loaders, rubber-tire backhoes, and compact excavators.
3. Torque-to-Capacity Correlation
Helical foundations are well-suited for heavy loads thanks to the relationship between installation torque and capacity. GoliathTech helical piles are installed deep into the ground and transfer loads into higher-bearing soils. As a helical pile moves deeper into increasingly denser soil, torque increases. Moreover, higher installation torque means a pile has a greater axial load capacity.
4. No Excavation Needed or Spoils to Remove
Because helical piles are displacement piles, no excavation is necessary during installation. To install concrete piles or any other type of replacement pile, soil must be drilled and extracted in order to make room for the concrete. Furthermore, any concrete brought onto the job site that doesn’t cure correctly or meet specification requirements will have to be removed — not to mention the waste and spillage.
5. Installs in any Weather
Mixing and pouring concrete in cold weather can be problematic and expensive. In subzero temperatures, concrete must be kept from freezing in both the mixing and curing stages. Meanwhile, helical piles can be installed regardless of climate or weather conditions.