Micropiles are deep foundation friction piles that are drilled, grouted, and reinforced with a central steel core, a high-strength steel pipe casing, or a combination of the two. A friction pile enables the distribution of pressure put on them to surrounding soil. The created friction creates an adhesive effect where the pile and the soil meet. Micropiles are a great solution for adjacent buildings, unstable foundations, and limited-access job sites. Micropiles are most often used in areas where two foundations and structures are in close proximity to each other, a common challenge for other foundation repair options due to constructability.
In this article, we are going to take a deeper look into micropiles and their uses.
The History of Micropiles
Micropile foundation technology has attained a greater demand and interest in recent years. With the shift in land development, foundation repair, and other construction trends, micropiles has sparked the interest of many design building professionals and foundation contractors. What most people don’t know is that micropiles have quite the history. After many structures were destroyed after World War II in 1945, engineers needed to figure out a new way to underpin them to make the necessary repairs. An Italian engineer ended up inventing micropiles as a foundational technology for structural reinforcement. Micropiles were first used in the 1950s, eventually being used to stabilize and rebuild structures throughout Europe. In 1973, micropiles finally made their way into the states, and since the foundational system has taken off. Today, there are a variety of micropile types and installation methods that have changed foundation repair and construction.
How Do Micropiles Work
Micropiles are most often used in densely populated areas that contain poor soil conditions or foundations that are in close proximity to each other. Small elements are driven into the soil with rotary hydraulic equipment and utilize a grouting process to reach the capacities needed for the foundation and the structure. Some micropiles are manufactured to be as strong and sturdy as traditional piles, but most types of micropiles are a much quicker and efficient method. Check out some situations where micropiles are needed.
- During seismic retrofitting
- Where extra structure support is needed during renovations
- In areas where the use of other methods is improbable
- In areas that structures have been damaged by adjacent excavation, dewatering, or tunneling
- During replacement of damaged foundation systems
What Is Micropile Underpinning?
Underpinning is a term that is often associated with these friction piles. Micropile underpinning is the process of small drilled and grouted friction piles. Hollow bars are then installed and pumped full of a cement grout mixture while an anchor is drilled into the grout. This can help extend the depth of range of a foundation so that its weight is more evenly distributed and have more support. The underpinning process is generally used when foundations have visible cracks and can help provide a structure with the stability and support needed to last for generations.
A pile will generally bear its load through contact and friction created between it and surrounding soil or grout. However, in areas that have rocky soil or solid layers of rock beneath a foundation, micropiles can be secured within the rock, gaining load bearing capabilities from the solid ground. As mentioned, in addition to being beneficial in areas with poor soil conditions, micropiles can work in congested areas and areas that need less obtrusive installation methods. Because these piles are installed vertically, they are ideal for tight spaces that some machinery cannot even fit in. In addition, micropiles are durable and affordable option with quicker installation times than any other method. Let’s take a look at some of the other benefits of micropiles:
- Relatively quiet installation process
- Can be installed near existing structures
- Provides a high-load capacity at a low settlement
- Resistant to compressive, lateral, or tensile loads
- Can be installed through almost any ground condition, obstruction or foundation
- Can be installed at any inclination
Choose Magnum Micropile Products
Micropiles can help structures attain the stability and support they need to last for generations. However, only quality and durable micropile products will be able to withstand the test of time. That’s why foundation contractors rely on Magnum Piering products for their foundational repair needs. As a leading manufacturer of steel piling products for deep foundations and foundational repair you won’t have to worry about the integrity of your structure. To learn more about the micropiling process and products, visit Magnum Piering today.