Rock Bolt Design Calculator
Professional Geotechnical Design Solutions
Based on AS4678-2002, AS5100 | Bar-Grout & Grout-Rock Interface
Input Properties
Concrete Properties
MPa
0.0000 MPa
f'ct = 0.36√f'c (Ultimate anchorage bond strength)
Anchor Properties
mm
kN
From manufacturer catalog
Grout/Drilled Hole
mm
kPa
Ultimate bond stress
Reduction Factors
AS5100.3 Table 7.3.3 & AS5100.6 Table 3.2
Table 7.3.3(A) AS5100.3
AS5100.6 Table 3.2
AS5100.6 Table 3.2
Table 7.3.3(B) AS5100.3
Results
Working Load in Rock Bolt
Design steel tensile capacity
φs3 = φn × φstr =0.000
Fs = Fu × φs3
0.00
kN
Fs = 310 × 0.000 = 0.00 kN
Bond Length (Bar-Grout)
Cement grout/bar bond stress
φs2 = φn × φ =0.000
Lb = Fu / (d×π×f'ct×φs2)
0.000
m
From: Fs = d × π × τbond × Lb
Bond Length (Grout-Rock)
Cement grout/rock bond stress
φs1 = φn × φg =0.0000
Lb = Fu / (D×π×τr×φs1)
0.000
m
From: Fs = D × π × τr × Lb × φg × φn
Quick Reference - Australian Standards
Table 7.3.3(A) - φn
• Service <6mo = 1.0
• Service <2yr = 0.93
• Permanent = 0.7
AS5100.6 Table 3.2 - φstr
• Axial tension = 0.9
• Bolt shear/tension = 0.8
AS4678-2002 Table B2
• φk (Tendon) = 0.9
• φb (Bond) = 0.7
Table 7.3.3(B) - φg
• Site tests = 0.55-0.65
• CPT = 0.45, SPT = 0.375