DYWI® Drill Hollow Bar
DYWIDAG’s Hollow Bar Micropile system combines drilling, grouting, and reinforcement in one solution. Ideal for limited-access sites, unstable ground, and aggressive schedules. From tunnelling, to bridge retrofits, our Hollow Bar Micropiles are engineered for speed, stability, and strength - even in the most complex geotechnical environments.
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Fast to install and high-performing
DYWIDAG’s DYWI® Drill Hollow Bar Micropile combines drilling, pressure‑grouting, and reinforcement in a single efficient operation, making it ideal for restricted-access sites, tight urban environments, unstable ground, or for projects where speed is critical.
This self-drilling micropile system is designed to support structures by transferring loads to deeper, more stable soil or rock. Whether you're underpinning an existing foundation, constructing a bridge abutment, or building in urban environments, DYWI® Drill provides reliable, high-capacity load transfer without the need for casing or pre-drilling.
Key features
Single pass installation
DYWI® Drill micropiles are installed using a single operation that combines drilling, grouting, and reinforcement. This reduces equipment needs, speeds up timelines, and eliminates the need for casing — even in collapsing ground conditions.
Performs in poor ground conditions
From loose fill to collapsing soils, the self-drilling design enables fast penetration and immediate support. The sacrificial drill bit and pressure-grouted bar ensure a strong bond where conventional piles can’t be used.
Ideal for restricted access sites
With compact rig compatibility, modular bar lengths, and a lightweight design, the system can be installed in basements, tunnels, urban infill locations, or beneath existing structures — wherever space is limited or headroom is tight.
High load-bearing capacity
Designed for tension, compression, and combined loading, the system can handle substantial structural demands. It's suitable for new construction or retrofitting foundations that require reliable deep-ground load transfer.
Demonstrated success in demanding environments
DYWI® Drill Hollow Bar Micropiles are designed to deliver reliable load transfer in the most challenging ground conditions — from soft clays to collapsing soils. The system accommodates compression, tension, or combined loads, making it ideal for both new foundations and structural retrofits.
Available in a range of bar diameters (R25–R51 and T76–T103), the fully threaded hollow bars offer:
High tensile strength to suit deep foundation demands
Grout injection through the bar for full encapsulation and strong bond
Rotary-percussive drilling that ensures fast penetration and minimal vibration
Adaptability to variable depths and loads through on-site bar coupling
In Colombia, DYWI® Drill T76-1900 micropiles were used to construct bridge foundations in loose, collapsing fill. The system enabled drilling rates of over 60 m/day per crew, helping complete the two successive cantilever bridges on an accelerated schedule.
For engineers and contractors, the combination of technical reliability, install speed, and site flexibility makes DYWI® Drill a proven choice for time-sensitive or geotechnically complex micropile applications.
