The following physical properties are established for type approval purposes.
Bolt Tensile Strength (MPa)
End Termination Tensile Load (kN)
Torque on Bolt Shank (Nm)
Values quoted are nominal values.
Quality Control Testing for shear strength (MPa) is carried out on each batch to ensure minimum values are maintained.
Bolt Tensile Strength
Nominal Tensile Strength has been established using ASTM D3916.
The specified gripping method has however been modified to more closely replicate the bolt application. An independent ISO 9001 certified testing laboratory carries out the above test.
Strength of End Termination
The bolt is grouted into a test block and a tensile load is applied to the nut by a hollow hydraulic ram. The value quoted is the nominal breakout load calculated from the pressure reading from an independently calibrated pressure gauge.
Torsional Strength of the Bolt
Torsional Strength is established by rotating a locked double nut against the non threaded end of the encapsulated bolt. The reading is taken from a commercial torque wrench.
Bolt Shear Strength
Shear Strength is established using ASTM D732. Shear is measured using a double sided jig at 90 degrees to fibre orientation to simulate rockbolt behaviour in situ. To conform to rock bolting practice the double sided shear value is halved and quoted as a single shear value. A minimum of 1 in 5,000 bolts is tested to ensure that all product is above the minimum value quoted. The mean of each batch will be more than 3 standard deviations above the minimum requirement. An independent ISO 9001 certified testing laboratory carries out testing.