R28 Self-Drilling Anchor Bolt
The R28 Self-Drilling Anchor Bolt is designed for medium-depth soil stabilization and medium-to-high load applications.
Introduction
The R28 Self-Drilling Anchor Bolt is designed for medium-depth soil stabilization and medium-to-high load applications. Compared with the R25 model, it features an optimized bar diameter and enhanced mechanical performance, achieving an ideal balance between construction efficiency and load-bearing capacity. It serves as a cost-effective upgraded solution for slope stabilization, tunnel pre-support, foundation pit support, and other geotechnical engineering applications.
Product Specifications
Hollow Anchor Bar
| Size | Outer Dia. | Ultimate Load | Yield Load | Weight | |||||
| mm | in | kN | kips | kN | kips | kg/m | lbs/ft | ||
 |
SER28S | 28 | 1.10 | 320 | 72 | 260 | 59 | 3.60 | 2.42 |
| SER28N | 28 | 1.10 | 260 | 59 | 200 | 45 | 2.90 | 1.95 | |
| Note： 1. Customized products are available based on your specific requirements； 2. 1mm=0.03937in 1kN=0.225kips 1MPa=0.1450377ksi 1kg/m=0.672 lbs/ft |
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Coupler
| Size | Outer Dia. | Length | Weight | Note | |||||
| mm | in | mm | in | kg | lbs | ||||
 |
SSR28 | 36 | 1.42 | 150 | 5.91 | 0.53 | 1.17 | With sealing ring | |
| SER28 | 36 | 1.42 | 150 | 5.91 | 0.55 | 1.21 | Without sealing ring | ||
Hex Nut
| Size | Key Size | Length | Weight | Note | |||||
| mm | in | mm | in | kg | lbs | ||||
 |
SSR28 | 46 | 1.81 | 45 | 1.77 | 0.44 | 0.97 | Heat treatment | |
Domed Nut
| Size | Key Size | Length | Weight | Note | |||||
| mm | in | mm | in | kg | lbs | ||||
 |
SSR28 | 46 | 1.81 | 45 | 1.77 | 0.45 | 0.99 | Heat treatment | |
Domed Plate
| Size | Dimensions | Thickness | Hole Dia. | Weight | |||||
| mm | in | mm | in | mm | in | kg | lbs | ||
 |
SER28 | 150×150 | 5.91×5.91 | 5 | 0.20 | 34 | 1.34 | 0.85 | 1.87 |
| 150×150 | 5.91×5.91 | 8 | 0.31 | 34 | 1.34 | 1.38 | 3.04 | ||
| 175×175 | 6.89×6.89 | 8 | 0.31 | 34 | 1.34 | 1.90 | 4.18 | ||
| 200×200 | 7.87×7.87 | 8 | 0.31 | 34 | 1.34 | 2.50 | 5.50 | ||
| 200×200 | 7.87×7.87 | 10 | 0.39 | 34 | 1.34 | 2.94 | 6.47 | ||
| 200×200 | 7.87×7.87 | 12 | 0.47 | 34 | 1.34 | 3.84 | 8.45 | ||
Drill Bit
| Size | Outer Dia. | Application (Advice) | |||||
| mm | in | ||||||
 |
EXX | Softer sedimentary rocks such as marls, mudstones, siltstone | |||||
| SSR28/42 | 42 | 1.65 | |||||
 |
ES-F | Gravel, soft rock | |||||
| SSR28/42 | 42 | 1.65 | |||||
 |
ESS-F | Weathered rock, stone walls, rubble | |||||
| SSR28/38 | 38 | 1.50 | |||||
| SSR28/42 | 42 | 1.65 | |||||
| SSR28/45 | 45 | 1.77 | |||||
Features
1. Higher Mechanical Performance Margin
The increased cross-sectional area of the self-drilling anchor bolt significantly improves its load-bearing performance. The ultimate tensile capacity can reach 260–320 kN, while the yield capacity can reach 200–260 kN, meeting the requirements of medium-to-high load support conditions. It is suitable for 15–25 m medium-to-high slopes and permanent support in medium-sized tunnels.
With higher bar rigidity, the R28 self-drilling anchor bolt provides improved resistance to torsion and bending deformation. During installation in fractured rock masses and soft rock formations, the rock bolt is less likely to bend or deform, offering better adaptability to complex geological conditions.
2. Better Cost Control
The load-bearing capacity is increased by approximately 30%, while the increase in material cost is controlled within 20%. Under medium-to-high load conditions, a single R28 self-drilling anchor bolt can replace 2–3 R25 self-drilling anchor bolts, reducing reinforcement density and lowering overall construction costs.
The improved grouting efficiency helps shorten the grouting time per borehole and accelerate the construction process, making it particularly suitable for time-sensitive emergency reinforcement projects and large-scale ground support applications.
