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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Geotechnical product range - Brochure (Germany)
Geotechnical Equipment - Brochure (Germany)
Z-14.4-674 - DYWI Drill Hollow Bar with Couplers and Anchorages - Approval
Geotechnical product range - Brochure (South America)
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.
Construction site service and equipment rental
Nagelprüfungen
Statische Probebelastungen
Bauseitige Schulungen oder Hilfestellung bei Problemen
Vermietung von Spann- Nail testing
Static load testing
On-site training or assistance with problems
Rental of tensioning presses, hydraulic units, load cells, etc.pressen, Hydraulikaggregaten, Kraftmessdosen, etc.
Manufactured to the highest standards
The DYWI® Drill hollow bar is a fully threaded, self-drilling solution for applications in civil engineering, including soil nailing, slope stabilization, micropiles, and rock anchoring. The design allows simultaneous drilling and grouting, eliminating the need for casing in weak or brittle soils - streamlining installation while meeting industry safety and quality standards.
Manufactured to the highest standards and compliant with regulations across the globe, DYWI® Drill Hollow Bar ensures reliable performance in critical geotechnical projects. The DYWI® Drill Hollow Bar is rigorously tested to ensure consistent performance in critical geotechnical applications. Its use supports compliance with project-specific specifications, environmental considerations, and relevant local codes.
Reinforcing safety, stability, and specification compliance
Beyond its technical adaptability, the system enhances structural integrity by reinforcing unstable ground and safely transferring loads. Whether used for slope stabilization, retaining wall support, or foundation reinforcement, DYWI® Drill provides a robust, durable, and compliant solution trusted by engineers worldwide.
DYWI® Drill Hollow Bar applications
Foundations and Underpinning
Enhances load-bearing capacity and provides additional support for new or existing foundations, particularly in weak or variable soils.
Micropiling
Forms small-diameter piles ideal for confined spaces, low headroom, or where minimal vibration and ground disturbance are critical.
Temporary or Permanent Retaining Structures
Offers structural reinforcement for both short-term excavation walls and long-term retaining solutions in infrastructure or building projects.
Technical Specifications
To support a wide range of geotechnical applications, the DYWI® Drill Hollow Bar system is available with a comprehensive range of precision-engineered accessories. Each component is designed to ensure safe, efficient installation and performance.
Core Accessories
01 Plates: Available in various shapes and sizes, plates distribute loads evenly to the surface and ensure secure anchorage.
02 Nuts : Used to tension the hollow bar and lock it in place. Options include hex nuts, spherical nuts, and coupling nuts.
03 Injection Adapters: Enable efficient and controlled grout injection through the center of the bar.
04 Couplers: Allow for bar extensions, ensuring adaptability for varying installation depths.
Positioning and Spacing
05 Centralizers: Maintain the correct positioning of the bar within the borehole, optimizing grout coverage and structural integrity.
Drilling Tools & Interfaces
06 Drill Bits: Available in multiple shapes and hardness levels to suit different ground conditions—from soft soils to hard rock.
07 Drill Bit Adapters: Connect the drill bit securely to the bar and transfer torque during drilling.
08 Shank Adapters: Interface between drilling equipment and the hollow bar system for seamless operation.
Testing Equipment:
09 Tensile Test Equipment: For on-site pull-out testing to verify anchor performance and compliance.
10 Load Cell: Measures and records load during testing or tensioning operations.
All accessories are designed for compatibility with DYWI® Drill systems and are manufactured under strict quality controls to meet international standards and project-specific requirements.
Corrosion protection options
DYWI® Drill Hollow Bars are designed to perform in a wide range of environmental conditions—from dry inland soils to aggressive marine or chemically contaminated ground. To support both temporary and permanent applications, we offer flexible corrosion protection solutions tailored to project needs and service life expectations.
01 Grout Encapsulation - In many cases, DYWI® Drill Hollow Bars are installed with pressure-injected grout, creating an additional protective barrier that enhances durability and long-term performance.
02 Hot-Dip Galvanizing (HDG) - A cost-effective solution for general corrosion protection. The zinc coating forms a barrier that resists atmospheric corrosion and sacrificially protects exposed steel if damaged.
03 Epoxy Coating - Applied as a thick, durable layer, epoxy coating offers excellent protection against moisture, chemicals, and chloride intrusion—making it ideal for aggressive or marine environments.
Not sure what protection level your project needs? Our technical team can help you select the right system based on soil chemistry, exposure class, and design life.
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