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Prestressed hollow anchor bolt consists of steel shell-expansion anchor head, hollow anchor rod, grouting stopper, arch plate and nut. Coupling and grouting block are optional.
It is designed for hard rock at fractured zone with growing joints which may cause loosing of fractured rock and reducing of friction between rocks, resulting in loosing of surrounding rocks in larger area. Applying enough pre-stress would keep its stability.
Construction Method:
1) Drill the hole and clean
2) Insert the anchor bolt to the hole bottom
3) Prestress the anchor rod and assure the anchor head contacting closely with hole bottom, then rotates the anchor rod until it is fastened, and install stopper, plate and nut;
4) Apply pre-stress to the designed value ,use the stretching gauge of anchor bolt or spanner;
5) Connect of grouting joints to grout
Product Specification:
specification | GY25 | GY28 | GY32 |
external diameter(mm) | 25 | 28 | 32 |
Breaking load(KN) | ≥150-180 | ≥180-220 | ≥220-250 |
Interior diameter(mm) | ≥15 | ≥17 | ≥22 |
drilling diameter(mm) | 42 | 42 | 51 |
thread type | left hand | ||
standard length(m) | 1.0/1.5/2.0/2.5/3.0/3.5/4.0/4.5/5.0/6.0 | ||
length tolerance | ±2.5% | ||
high strength prestressed anchor bolt