Micropiles and Minipiles

Micropiles and Minipiles

Micropiles, also called minipiles, are small-diameter piles. They are constructed by drilling a hole typically 2 to 8 inches in diameter deep into the soil, inserting a high-strength threaded bar or pipe and then filling the hole with high-strength grout.

Primarily, a micropile is designed to take advantage of the friction developed where the grout and soil interface, but it also can incorporate some end-bearing capacity when drilled into competent strata or socketed into rock. Soil conditions and capacity requirements dictate hole size and depth as well as reinforcing type.

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Applications for Micropiles

Micropiles are typically used when ground conditions will not support the full load of construction or to strengthen the foundation of an existing structure. For example, they may be utilized when building in an area with unstable soils or various obstructions.

Micropiles are suitable for a range of conditions throughout the Southeast, including:

  • Deep foundations in difficult soil conditions
  • Temporary or permanent structural underpinning
  • Supporting heavy loads in congested areas
  • Mitigating foundation settlement
  • Excavation support in confined spaces

Drilling and Installing Micropiles

Many times, especially in clay soils, an open hole drilling method for micropile installation can be used. This simply means the soil is stiff enough to remain open during the entire operation of drilling, bar placement and grouting. Grouted micropiles are always installed from the bottom up using a tremie tube.

It is sometimes necessary to install temporary or permanent casing through the soft overburden to keep the soils from collapsing during pile installation. This drastically slows down the installation process and increases the cost. Alternatively, Foundation Repair Services can install hollow bar injection anchors when dealing with soft collapsing soils.

Hollow bar micropiles are constructed by injecting grout through a hollow steel bar and bit during the drilling process. The grout serves to stabilize the hole and flush the cuttings out during drilling. The hollow bar and bit serve as the drill string during installation and as the permanent reinforcement in the pile after completion.

This drilling method has several advantages. They include the speed of installation and the ability to achieve high capacities with relatively small piles.

Why Choose Foundation Repair Services?

We’re proud to be the micropiling contractors of choice for homeowners, builders and businesses throughout the region. As a fully licensed company, we’re dedicated to providing the highest levels of professionalism and expertise in all the work we do. Our focus is always on delivering effective, efficient solutions for our clients, from small repairs to complex, large-scale projects.

Let Us Manage Your Foundation Project

Request an Appointment

Charlotte: 704-545-0206 | Asheville: 828-274-2101 | South Carolina: 803-802-2477

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