Rock Bolt Tension Calculator

Reconcile actual calibrated bolt strain/preload tension with independent load cells, not axial stress×area design force, spacing or support readiness. Caller independently verifies units, applicability and matching conditions; no operational recipe, safety certification, causal efficacy or legal/resource classification is inferred.

Description

Calibrated axial stiffness and measured strain can infer bolt tension above an independently observed preload.

Calibrated axial stiffness and measured strain can infer bolt tension above an independently observed preload.^[1]

A separate load-cell record allows a signed reconciliation.

When to use Rock Bolt Tension Calculator

Use this tool to calculate or review the supplied observations under the stated rules. Match completed survey or ledger observations by block, segment or stage and confirm their units and boundaries.

How to use Rock Bolt Tension Calculator and understand its results

Match completed survey or ledger observations by block, segment or stage and confirm their units and boundaries.
Enter observedBoltStrains, callerMatchedAxialStiffnessN, callerIndependentlyMeasuredPreloadsN, observedIndependentLoadCellN, using the field meanings and rules below, then run the tool.
Read strainInferredBoltTensionsN, signedLoadCellMinusStrainTensionN. Inspect nested result fields where present, and review unknown records separately from known matches.
Correct any reported input issue and run again. Before using a successful result, check the stated units, signs, reference scope and observation coverage.

Input field	Meaning	Value type	Requirement
observedBoltStrains	Observed bolt strains	list of number	Required
callerMatchedAxialStiffnessN	Caller matched axial stiffness n	list of number	Required
callerIndependentlyMeasuredPreloadsN	Caller independently measured preloads n	list of number	Required
observedIndependentLoadCellN	Observed independent load cell n	list of number	Required

Use aligned nonnegative strains and preloads, positive axial stiffness in newtons, and finite independent load-cell forces. Compute strain×stiffness+preload and loadCell−inferred tension. No capacity check is implied.

tension_i=strain_i stiffness_i+preload_i; discrepancy_i=loadCell_i−tension_i

Use the matching field units and the exact boundary, ordering and reference rules above.

Output field	Meaning	Value type
strainInferredBoltTensionsN	Strain inferred bolt tensions n	list of number
signedLoadCellMinusStrainTensionN	Signed load cell minus strain tension n; preserve the subtraction order and sign defined in the mechanics	list of number

json

{
  "input": {
    "observedBoltStrains": [
      0.001,
      0.002
    ],
    "callerMatchedAxialStiffnessN": [
      10000,
      20000
    ],
    "callerIndependentlyMeasuredPreloadsN": [
      5,
      10
    ],
    "observedIndependentLoadCellN": [
      20,
      40
    ]
  },
  "output": {
    "strainInferredBoltTensionsN": [
      15,
      50
    ],
    "signedLoadCellMinusStrainTensionN": [
      5,
      -10
    ]
  }
}

Limitations and assumptions

Units, ledger boundaries, survey interpretation and model applicability must be independently established. These summaries do not assign reserve/resource classifications or establish support adequacy, ventilation safety or an operating setting.

Missing required fields, unknown fields, wrong types and violated rules return input issues. Numeric values and outputs must be finite. Lists and matrices must be dense, without missing cells. Numeric lists allow at most 10000 entries; ordinary string lists allow at most 128 strings of 128 UTF-16 units each; numeric matrices allow at most 128 rows and 128 columns, subject to narrower requirements above.

Alternative or Complementary methods

For a related step, use Rock Bolt Bond Strength Calculator: An apparent uniform bond shear divides a measured pullout force by the bonded cylindrical area. For a complementary comparison, use Steel Set Support Capacity Calculator: Installed steel-set loads and matched certified capacities describe a particular support inventory.

References

Rock Bolt Tension Calculator — tool.io

Similar or alternative tools

Rock Bolt Bond Strength Calculator
An apparent uniform bond shear divides a measured pullout force by the bonded cylindrical area.
Steel Set Support Capacity Calculator
Installed steel-set loads and matched certified capacities describe a particular support inventory.