As infrastructure projects push deeper into challenging ground conditions, geotechnical engineers require anchoring solutions that can withstand extreme tensile and shear forces while maintaining installation efficiency. SupAnchor, the No.1 manufacturer and exporter of self-drilling anchors in Asia, has expanded its portfolio with the Grade 75 self-drilling hollow anchor—a high-strength variant engineered for heavy-load and critical structural applications. This new product retains the core 3-in-1 principle that has made SupAnchor's self drilling anchor system a preferred choice worldwide, while delivering substantially higher ultimate and yield loads than standard-grade anchors.
The Grade 75 self-drilling hollow anchor is designed to address a growing market need: projects where conventional anchors may not meet force requirements due to deep soil layers, high overburden pressure, or permanent structural demands. By integrating high-strength steel with SupAnchor's proven ribbed hollow bar design, the anchor provides a reliable, efficient, and cost-effective solution for contractors and engineers facing complex geotechnical challenges.
At the heart of the Grade 75 self-drilling hollow anchor is its 3-in-1 integration: a sacrificial drilling rod, injection tube, and reinforcing bar combined into a single ribbed hollow steel bar. This design allows simultaneous drilling and grouting, eliminating the need for separate casing systems and significantly improving construction efficiency in unconsolidated or cohesive soils. For projects in difficult ground conditions, such as soft clay, sand, or fractured rock, the drill-and-grout bolt approach reduces installation steps and minimizes the risk of borehole collapse.
The use of Grade 75 high-strength steel provides a decisive advantage. Compared to standard carbon steel grades, this material offers significantly higher tensile and yield strength, enabling the anchor to withstand heavy tensile and shear forces. For instance, standard R thread models like R32N/20 offer an ultimate load of at least 280 kN, but the Grade 75 R32 model is inferred to deliver ultimate loads between 380 and 420 kN—an increase of over 35 percent. Similarly, the Grade 75 R38 model targets ultimate loads in the 550 to 600 kN range, making it suitable for the most demanding applications.
Standardized thread and rib design ensure compatibility and performance. The anchor's thread specifications align with ISO 10208 for R thread sizes, allowing on-site quick connection with standard nuts, couplers, and plates. The optimized relative rib area (fR = 0.21 - 0.33) maximizes bonding with grouting materials, while the 45-degree angled rib surfaces reduce splitting forces on surrounding soil or rock. At maximum load, crack widths remain below 0.1 mm, ensuring structural stability—a critical factor for permanent support systems in tunnels and slopes.
The following table highlights the inferred technical data for two representative Grade 75 R thread models:
| Parameter | Grade 75 R32 | Grade 75 R38 |
|---|---|---|
| Outside Diameter (mm) | 32 | 38 |
| Internal Diameter (mm) | 18-20 | 19-21 |
| Ultimate Load (kN) | 380-420 | 550-600 |
| Yield Load (kN) | 300-340 | 440-480 |
| Weight (kg/m) | 3.2-3.6 | 4.7-5.1 |
| Thread Type | ISO 10208 - R32 | ISO 10208 - R38 |
| Elongation (%) | A100mm ≥6% / Agt ≥5% / A200mm ≥6% | A100mm ≥6% / Agt ≥5% / A200mm ≥6% |
| Length (m) | x2, x3, x4, x5, x6, x7, x8 | x2, x3, x4, x5, x6, x7, x8 |
| Anchor Nut Size | SW46/L65 | SW55/L70 |
| Anchor Coupler Size | D42/L190 | D50/L210 |
| Anchor Plate Size | 200 x 200 x 12 | 250 x 250 x 16 |
These parameters illustrate how the Grade 75 series extends SupAnchor's self drilling anchor bolt lineup to handle higher forces without sacrificing installation convenience. The increased cross-sectional area and optimized steel grade directly translate into greater pullout resistance and long-term reliability.
Another key advantage is compatibility with SupAnchor's anti-corrosion treatments. Hot-dip galvanizing and SupCoating options can be applied to Grade 75 anchors, extending their service life in moderately corrosive environments. This combination of high strength and corrosion resistance allows the anchor to function in inland heavy-duty infrastructure with damp soil, as well as in near-coastal applications where durability is essential.
The Grade 75 self-drilling hollow anchor is specifically positioned for projects that demand high load-bearing capacity and permanent reliability. Deep foundation reinforcement for high-rise buildings, load-bearing support for large-span bridges, anchoring of industrial heavy machinery, and reinforcement of large-scale water conservancy structures all benefit from the anchor's superior strength. In these scenarios, the geotechnical reinforcement system must resist not only static loads but also dynamic forces and long-term settlement, making Grade 75 a prudent choice.
Challenging ground and tunnel projects are another primary application area. Deep tunnel excavation in complex geological conditions—such as highway or railway tunnels through fault zones or highly fractured rock—requires support elements that can withstand high ground pressure. Similarly, stabilization of high and steep slopes with large soil pressure or anchoring in soft soil with high settlement risks demands anchors that do not yield under load. The Grade 75 hollow bar anchor provides the necessary tensile capacity, while the 3-in-1 installation method reduces construction time and risk in unstable ground.
For critical structural permanent support, such as nuclear power plant auxiliary structures, large-scale industrial workshop foundations, or high-pressure pipeline support systems, long-term load-bearing reliability is non-negotiable. The Grade 75 anchor's high-strength steel and controlled elongation properties ensure that it can maintain structural integrity over decades, even under fluctuating loads and environmental stresses.
From an industry perspective, the introduction of high-strength self-drilling anchors reflects a broader trend in geotechnical engineering: the need for efficient, safe, and high-capacity solutions amid urbanization and infrastructure renewal. As global investment in transportation, energy, and water infrastructure grows, products like the Grade 75 anchor enable contractors to complete projects faster while meeting stricter safety and performance standards. The ability to combine drilling and grouting in one pass reduces equipment needs, labor costs, and environmental impact—making it attractive for both developed and emerging markets.
SupAnchor has earned its position as the leading manufacturer and exporter of self-drilling anchors in Asia through continuous research and development, adherence to international standards, and a commitment to professional, innovative, and collaborative engineering. The company's self drilling anchor system is used in major infrastructure projects across the globe, from deep basements in Europe to mining operations in Australia and tunneling in the Americas.
The Grade 75 variant is a direct response to customer feedback and field requirements. By leveraging its in-house R&D capabilities, SupAnchor has developed a product that maintains the ease of use of its standard R and T thread anchors while pushing the performance envelope. Compliance with ISO 10208 thread standards ensures interchangeability with existing accessories, minimizing the learning curve for contractors and reducing inventory complexity.
SupAnchor's commitment to quality extends beyond the anchor bar itself. The company provides complete geotechnical reinforcement system packages, including nuts, couplers, plates, and anti-corrosion coatings, all designed to work seamlessly together. This system-level approach ensures that every component meets the same high standards, reducing the risk of premature failure and enhancing overall project safety.
In conclusion, the new Grade 75 self-drilling hollow anchor represents a significant step forward for high-load geotechnical applications. With its high-strength steel core, proven 3-in-1 design, and compatibility with SupAnchor's extensive accessory range, it offers engineers a reliable and efficient solution for the most demanding projects. Whether for deep foundations, heavy tunnel support, or permanent critical structures, the Grade 75 anchor delivers the performance, durability, and installation efficiency that modern infrastructure demands.
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