Hollow Bar Micropiles are slender foundation elements installed using a hollow, fully threaded steel bar that functions as both the drilling tool and the structural reinforcement, enabling drilling and grouting to occur at the same time.
Our hollow bar injection-bore micropile system provides a cost-effective deep foundation solution for projects facing difficult soil conditions, including collapsible soils, large boulders, and subsurface obstructions. This system is ideal for sites where traditional foundation methods or conventional micropiles are impractical.
Installation is completed in a single, top-down operation, minimizing disruption and improving efficiency. The hollow, continuously threaded steel bar functions as the drill string and structural reinforcement, eliminating the need for open-hole drilling. During drilling, a high-pressure neat cement grout is pumped through the hollow bar. This grout acts as both the drilling medium and the load-bearing reinforcement of the micropile.
As the grout exits through ports in the sacrificial drill bit, it permeates into the surrounding loose or unstable soils.
This controlled injection process creates a competent reinforced grout column that:
-Enhances load-bearing capacity
-Improves soil-to-pile bond
-Provides reliable structural support in poor ground conditions
The resulting grout column strengthens the surrounding soils while forming a durable, high-capacity micropile foundation.
Hollow bar injection-bore micropiles offer an economical and effective foundation alternative for:
-Obstructed or variable subsurface conditions
-Restricted access sites
-Projects requiring minimal vibration and disturbance
This system delivers dependable performance where other deep foundation methods may fall short.
