Self-Drilling Anchor Bolts
Self Drilling Anchor Bolts are a bolting solution for unstable ground conditions such as sand, gravel, silt, and clays, and in soft to medium fractured rock formations.
For projects facing such ground conditions, self-drilling anchors should be considered as the main productivity solution. Self-Drilling Anchors from Intech Anchoring Systems are designed for optimized installation, tailored to the project’s needs.
By drilling a hole in collapsing soil or loose rock, with a sacrificial drill bit and a hollow rod, and after the drilling operation injecting cementitious grout or resin into the hollow rod and surrounding cavity, self-drilling anchors are a top productivity solution.
Self drilling anchor bolts from Intech Anchoring Systems consists of:
- A hexagonal nut
- A bearing plate
- Extension couplings, if the anchor consists of several anchor rod sections
- Hollow anchor rod(s)
- A sacrificial drill bit
Applications of Self-Drilling Anchors
Slope stabilization
Foundations with micropiles
SDA micropiles can be defined as drilled piles, composed of injected grout with the anchor rod as steel reinforcement. They can be installed in sites with limited space using light drilling equipment, can be installed into most ground conditions including rock and are suitable for tension and compression loads. The big advantage is the combined drilling and grouting making high piling outputs possible.
Tunneling
Self-Drilling Anchor Equipment & Drill Bits
Sacrificial drill bits
The sacrificial drill bit is the most crucial part of the anchoring system and is responsible for the productivity of the installation. Intech Anchoring Systems offers a large range of drill bits to suit the changing geology encountered during projects. In order to improve on performance and cost efficiency, data is collected from projects around the world and incorporated into the design with the goal to improve penetration rate and bit quality and to reduce manufacturing and application costs.
The selection of drill bits
- High quality for a limited service life
- Installed MAI SDA length
- Geology
- Geometry
SDA Anchor Components
Hollow anchor rods
Extension couplings
The coupling features a patented design that enables direct end-to-end energy transmission between each bar, reducing losses and ensuring maximum percussive energy at the drill bit. To enable the correct seating of each bar within the coupler, all bars are chamfered with precision to enable the bar ends to have face-to-face contact.
Bearing plates
The bearing plates are forged steel plates with a center hole, allowing articulation of seven degrees in all directions. Intech Anchoring provides customized bearing plates for each application
Hexagonal nuts
Galvanized anchors
Corrosion is a very complex process, and corrosion rates are very hard to predict accurately. However, analytical evaluations can be helpful to recommend the need for corrosion protected rock bolts. The full range of SDA bars and accessories is available with this corrosion protection.
Coupling adapters
Manufactured from thick-wall steel which is machined and case hardened, coupling adapters are used at high wear locations, typically just below the hammer drive. A locking torque is normally applied to the coupling box at the permanent joint to avoid release when additional anchor bars are added. All the coupling adapters are supplied with a bridge to act as a center stop. When a step-down (reducer) drive arrangement is used i.e. R38 shank to drive to install R32 anchor bar, a locking torque should be applied at the R38 end to prevent the R32 bar from climbing into the R38 chamber. Step-up drive arrangements are not recommended as the additional torque overloads the smaller drive.
Shanks
Rotary percussion is the preferred method of installation. Either a hydraulic or air hammer is suitable. To transfer the rotation and percussion from the hammer to the bar‘s system, there is a need for a shank adapter. Intech Anchoring Systems provides a full range of different shank adapters for different hammers and an inventory of shanks for the drills.
Grout coupling
After using standard flushing media (water or air), grouting must be done. For connecting the grouting hose from the pump with the anchor bar, the grout swivel is used. The grout swivel will be removed and reused after the grouting process is done
Why Intech Anchoring Systems?
In addition to materials and service, Intech Anchoring Systems will provide continual support through the entire project, including engineering/design, on-site support, load testing, installation expertise, competitive pricing, and rental equipment. Call us at 800-223-7015 for more information.