Rock Bolts – Friction Bolt
|Yield Strength||345MPa / 120kN||445MPa / 160kN|
|Tensile Strength||460MPa / 165kN||510MPa / 180kN|
|Friction Bolt Diameter||47mm|
|Hole Diameter Range||43mm min./45.5mm max.|
|Mass per Metre||2.79kg|
|Cross Sectional Area||355mm²|
DSI Underground Hyperthane Friction Bolts are an improved point anchoring Ø47mm friction bolt. The fundamental principle of the system is to enhance point loading in the toe while retaining standard installation procedures. Unlike grout or cement, the Hyperthane insert is made from a highly elastic material and wont fracture if the bolt buckles. This ensures that the Hyperthane Bolt will hold load before and after ground movement.
- The bolts are manufactured from high strength steel tube with urethane insert at the toe and a slot along its entire length. A ring is welded on the outer end to hold a dome plate to the surface
- The friction bolt can be load tested by fitting a special collar to the bolt prior to installation. Pull tests can then be performed using a hollow ram hydraulic jack.
Installation Guide Lines
The procedure used to install a Hyperthane bolt is the same as a typical Friction bolt and that is:
- Drill a bore hole
- Drive the bolt with percussion until the load plate is pressed firmly against the wall.
- The time taken to drive a Hyperthane bolt into a bore hole may be slightly longer than when installing a regular friction bolt. Generally if Hyperthane bolts are having longer installation times than standard friction bolts "the bore holes should not be made larger to reduce installation time."
- On occasions where considerations are given for the Hyperthane bolt to require a slightly larger hole than regular friction bolts, it is important to consult with your local DSI Underground representative first.
- 47mm Hyperthane Friction Bolts are NOT suitable for installation with hand held rock drills (bolters/stopers).