In today’s demanding infrastructure and mining projects, engineers increasingly face challenging ground conditions such as soft rock, clay, and water-bearing strata. Traditional anchoring methods often require separate drilling and grouting steps, leading to time-consuming installations and compromised borehole stability. Addressing these challenges, SupAnchor has introduced the groundbreaking GFRP SDA Bolt—a fully integrated self drilling anchor system that combines drilling, grouting, and anchoring into one seamless process.
The SupFRP® GFRP SDA Bolt is specifically designed for applications like tunnel face stabilization, forepoling, slope stabilization, and ground support in soft rock. Its glass fiber reinforced polymer composition offers not only high tensile strength but also complete corrosion resistance, making it a permanent solution for civil and mining engineering.
At the heart of this self drilling anchor bolt is a central hollow core that permits water flushing during drilling and subsequent grout injection. This drill-and-grout bolt functionality eliminates the risk of borehole collapse in loose or fractured ground, a common problem when using separate casing systems. The GFRP material is lightweight yet incredibly strong, and its cuttability greatly reduces the risk of damaging tunneling machinery when drifting or enlarging tunnels. Contractors can simply cut protruding bolt ends without heavy equipment, streamlining the workflow. The unique waved thread profile on the bolt surface, which contributes to the outside diameter, increases the mechanical interlock with the grout, resulting in superior bond strength. This feature, combined with the high tensile E-modulus of 45 GPa, ensures that the composite anchor delivers elastic behavior comparable to steel while remaining non-corrosive and non-magnetic.
The hollow bar anchor is available in four sizes: H25S, H28S, H32S, and H38S, covering diameters from 25 mm to 38 mm. Each variant adheres to ISO standard thread profiles (R25, R28, R32, R38), ensuring compatibility with off-the-shelf accessories and reducing procurement complexities. Installation requires no special equipment beyond a standard rotary-percussive drill and a grout pump. The hollow bar is connected to the drill via an adapter, and drilling proceeds with water flushing. Once desired depth is reached, the drill is disconnected, and grout is injected through the central bore, filling the annular space and consolidating the surrounding ground. The process is continuous, eliminating time lost to casing extraction and secondary grouting.
The comprehensive technical data below highlights the robust performance of the GFRP SDA Bolt across all sizes. The guaranteed tensile loads and torsion strengths scale with diameter, allowing engineers to select the optimal configuration for their project.
| Parameter | H25S | H28S | H32S | H38S |
|---|---|---|---|---|
| Outside Diameter (mm) | 25 | 28 | 32 | 38 |
| Internal Diameter (mm) | 12 | 14 | 15 | 20 |
| Nominal Cross Sectional Area (mm²)* | 250 | 310 | 400 | 540 |
| Guaranteed Tensile Load (kN) | 220 | 280 | 365 | 490 |
| Tensile E-Modulus (GPa) | 45 | 45 | 45 | 45 |
| Torsion Strength (Nm) | 180 | 250 | 360 | 450 |
| Ultimate Strain | 2.0% | 2.0% | 2.0% | 2.0% |
| Weight (kg/m) | 0.63 | 0.86 | 0.99 | 1.33 |
| Thread Type (ISO) | R25 | R28 | R32 | R38 |
| Standard Lengths (m) | 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 | 2–11 | 2–11 | 2–11 |
*Nominal cross sectional area represents the characteristic stress value in the core, given in mm².
The progressive tensile loads—from 220 kN for the H25S to 490 kN for the H38S—ensure that this geotechnical reinforcement system meets the demands of deep tunnels and high slopes. Despite its high strength, the GFRP bolt weighs up to 80% less than equivalent steel anchors, reducing handling labor and transportation costs.
On a recent light rail project in the northwestern United States, contractors encountered a 300-meter section of saturated clayey silt with frequent groundwater inflows. Conventional self-drilling steel anchors required extensive pre-grouting to control the inflow, causing delays. Switching to the SupFRP® GFRP SDA Bolt H32S allowed simultaneous drilling and flushing, stabilizing the borehole immediately and enabling rapid installation of face stabilization bolts. The lightweight nature of the GFRP bars also reduced worker fatigue and equipment wear.
Similarly, in a large-scale slope remediation project in the Italian Alps, the corrosion-free property of the GFRP bolt was a decisive factor. With high sulfate content in the groundwater, steel anchors would have needed complex encapsulation systems. The SupAnchor solution eliminated that need, cutting material costs by 20% and accelerating the works schedule. The permanent support required no maintenance, a key factor for the environmentally sensitive area.
For tunnel face stabilization in soft ground, the self drilling anchor bolt can be rapidly installed with standard hydraulic rotary drills. The integrated drilling and grouting minimizes over-excavation and material loss. In slope stabilization, the system serves as a permanent soil nail system, its corrosion resistance eliminating the need for double corrosion protection (DCP) layers. Mining operations benefit from the bolt’s cuttability during drift enlargement, as cut portions can be removed without damaging continuous miners or roadheaders.
The hollow bar anchor also excels in water-rich formations. The flushing mechanism clears cuttings effectively, maintaining borehole integrity and ensuring a high-quality grout bond. This reduces the risk of debonding and enhances the long-term reliability of the anchor. Installation crews report that the consistent thread form and lightweight design reduce installation time by 30–40% compared to traditional solid bar systems.
The global demand for efficient ground anchor bolt factory products is rising as infrastructure projects grow in complexity and scale. SupAnchor’s GFRP SDA Bolt positions itself as a frontrunner by addressing key pain points: installation speed, worker safety, and lifecycle durability. Unlike traditional threaded bar systems that require separate casings, this drill-and-grout bolt simplifies logistics and slashes installation time by up to 50%.
Regions with aggressive ground chemistry, such as coastal areas or sulfide-rich rock, particularly benefit from the non-metallic composition. The GFRP material will not corrode, ensuring a maintenance-free service life of over 100 years—a dramatic improvement over steel anchors that may require cathodic protection. This longevity aligns with sustainable construction objectives, reducing material waste and lifecycle costs.
For over two decades, SupAnchor has been a trusted name in geotechnical and mining support solutions. With ISO-certified manufacturing and a global project portfolio spanning high-speed railways, subway systems, and open-pit mines, the company consistently delivers Professional, Innovative, and Collaborative solutions. The GFRP SDA Bolt is the latest example of its commitment to advancing ground reinforcement technology.
With this launch, SupAnchor reaffirms its role as a premier soil nail system manufacturer, offering products that combine cutting-edge material science with practical job-site requirements. Engineering teams around the world can now access a self drilling anchor system that redefines what is possible in difficult ground.
SupAnchor's self drilling anchor system played a pivotal role in stabilizing steep slopes during a major highway expansion in the Alps, demonstrating advanced geotechnical reinforcement capabilities.
SupAnchor introduces the SupFRP GFRP Tie Rod, a corrosion-resistant, non-removable formwork solution that cuts costs and improves safety. Learn about its technical advantages and global impact.
SupAnchor's self drilling anchor system plays a critical role in a challenging European infrastructure project, providing efficient ground stabilization and geotechnical reinforcement in difficult soil conditions.
SupAnchor introduces the SupHulk PM series friction rock bolts, offering immediate load-bearing capacity and full-column friction support for mining and tunneling applications. The system features high yield loads and adapts to varied rock conditions.
SupAnchor's self drilling anchor system was deployed in a European alpine tunnel project, solving complex geological challenges with a single-pass drill-and-grout solution, highlighting the strength of hollow bar anchors.
