In an era where underground construction and slope stabilization demand ever-more reliable reinforcement solutions, SupAnchor has introduced its latest innovation: the SupFRP® GFRP Hollow Injection Bolt. This advanced geotechnical reinforcement system seamlessly integrates the functions of a conventional rock bolt and a high-pressure injection mechanism, delivering unmatched performance in the most demanding geological conditions. From deep tunnels in the Alps to slope stabilization along North American highways, this hollow bar anchor is rapidly becoming the go-to choice for engineers seeking durability, lightweight handling, and full grouting capabilities.
Traditional anchoring methods often struggle in fractured rock, water-bearing strata, or confined spaces where access is limited. The SupAnchor GFRP Hollow Injection Bolt overcomes these hurdles by combining drilling, anchoring, and grouting into a single operation. After the drill-and-grout bolt is inserted, high-pressure grout is injected through its hollow core, permeating the surrounding rock mass and creating a robust bond. The bolt itself stays in place, bearing tensile loads together with the end plate and nut. This method not only reinforces the ground but also seals fissures, enhancing overall stability.
The bolt’s glass-fiber reinforced polymer (GFRP) composition brings several advantages over steel alternatives. It is 4–5 times lighter, making handling on steep slopes or in cramped tunnels far easier and safer. Its high corrosion resistance ensures longevity even in chemically aggressive environments, such as coastal or mining settings. Moreover, the material’s cuttability allows for easy section removal during tunneling without damaging cutting equipment, a critical benefit for TBM (Tunnel Boring Machine) operations.
The SupFRP® GFRP Hollow Injection Bolt is offered in multiple diameters and tensile capacities to suit diverse project requirements. All models feature a waved thread structure that enhances bond with grouting materials, a guaranteed tensile E-modulus of 45 GPa, and an ultimate strain of 2.0%. Pressure resistance stands at 5 MPa for most variants, with select high-strength models reaching up to 30 MPa. Below is a summary of key models currently available:
| Model | Outer Diameter (mm) | Inner Diameter (mm) | Guaranteed Tensile Load (kN) | Pressure Resistance (MPa) | Weight (kg/m) |
|---|---|---|---|---|---|
| H25/220 | 25 | 12 | 220 | 5 | 0.64 |
| H28/320 | 28 | 12 | 320 | 5 | 0.88 |
| H32/360 | 32 | 15 | 360 | 5 | 1.20 |
| H38/490 | 38 | 20 | 490 | 5 | 1.50 |
| H25/300 | 25 | 8 | 300 | 30 | 0.79 |
The table highlights the range from compact yet robust H25/220 to the heavy-duty H38/490. The H25/300 variant stands out with its exceptional 30 MPa pressure resistance, making it ideal for high-pressure grouting in waterlogged or fine-grained soils. All bolts can be supplied in lengths from 2 m to 11 m, with left- or right-hand threads to match drilling equipment.
These technical parameters directly address real-world engineering needs. For example, during the construction of a new metro line in Milan, engineers faced loose, water-saturated alluvium. Using the H32/360 self drilling anchor bolt, they achieved full grout encapsulation with minimal overhead loss, while the bolt’s 360 kN tensile load ensured permanent support for the station cavern. The lightweight nature (1.20 kg/m) reduced manual handling risks and sped up installation by 30% compared to steel alternatives.
The SupFRP® GFRP Hollow Injection Bolt shines across a spectrum of geotechnical engineering scenarios:
The global geotechnical reinforcement market is projected to grow significantly, driven by urbanization, underground infrastructure, and renewable energy projects (e.g., dam stabilizations, pumped-storage caverns). In this landscape, the SupAnchor hollow bar anchor offers a competitive edge by reducing material and labor costs while enhancing safety. A single bolt replaces the conventional two-step process of drilling and then installing a separate anchor and grout tube, cutting installation cycle times by up to 50%. Furthermore, the high-pressure injection capability (up to 30 MPa) ensures deeper grout penetration, consolidating the ground more effectively than low-pressure alternatives—a critical factor in today’s increasingly deeper excavations.
The product also aligns with sustainable construction trends. GFRP manufacturing has a lower carbon footprint compared to steel, and the extended service life reduces maintenance interventions. For clients specifying LEED or BREEAM credits, this becomes a decisive factor.
Founded on a philosophy of engineering excellence, SupAnchor has grown from a local ground anchor bolt factory to a global innovator in anchoring technology. With ISO 9001 and ISO 14001 certifications, the company maintains rigorous quality control from raw material sourcing to final testing. R&D investments have yielded patented thread geometries and optimized resin formulations that maximize the bolt–grout interface bond.
Collaboration defines SupAnchor’s approach. On a recent hydroelectric project in the Andes, site engineers needed a custom bolt length to suit fractured granite. SupAnchor’s technical team co-developed a 13-meter variant within weeks, demonstrating the brand’s flexibility and commitment to partnership. Today, SupAnchor products are found in over 40 countries, from the London Crossrail to the Singapore Deep Tunnel Sewerage System, silently securing the world’s most critical infrastructure.
As the construction industry pushes boundaries—deeper, longer, faster—the need for intelligent reinforcement systems grows. The SupFRP® GFRP Hollow Injection Bolt answers this call with a blend of scientific material design and practical site know-how. It is not merely a product but a comprehensive solution that embodies the brand’s core values: Professional, Innovative, Collaborative. For engineers around the globe, it signifies a step forward in making geotechnical works safer, faster, and more durable.
A major infrastructure project in the Alps successfully utilized SupAnchor's self-drilling anchor system to overcome fractured rock conditions, enhancing geotechnical safety and project efficiency.
SupAnchor launches a high-performance GFRP hollow injection bolt combining rock bolting and grouting, offering superior tensile load, pressure resistance, and corrosion protection for challenging geotechnical projects.
SupAnchor's self-drilling anchor system is being used in a critical slope stabilization project on a major Alpine highway expansion, overcoming difficult geology and ensuring long-term safety and infrastructure resilience.
SupAnchor's new GFRP Tie Rod offers high corrosion resistance and permanent application, eliminating removal costs in formwork projects globally.
SupAnchor's self-drilling anchor system successfully deployed in challenging Swiss Alpine tunnel, demonstrating reliability in fractured rock and water-bearing zones. The integrated drill-and-grout technology accelerated construction and enhanced safety.
