Turn a pull-test load on a bonded anchor into an average bond stress, or a bond stress into the load it represents at your diameter and embedment.
Anchor
Load to average bond stress
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Bond stress to load
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Bonded area π × d × hef: enter d and hef
Average bond stress = load ÷ (π × d × hef). Calculated with the free tool at calyx-ai.net/qa/bond-stress-calculator/ (Quality Tester Solutions LLC).
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What this number is, and what it is not
Average bond stress = load ÷ (π × d × hef): the load spread evenly over the surface of a cylinder with the anchor's diameter and the embedment depth. With load in newtons and lengths in mm the result is in MPa; psi = MPa × 145.0377 (exact factors: 1 lbf = 4.4482216152605 N, 1 in = 25.4 mm). Check: 30 kN on a 12 mm anchor at 100 mm embedment is 7.96 MPa.
It is an average, not the stress profile along the anchor, and the tool does not apply any reduction, edge, spacing or concrete factors. Which diameter goes into the formula (rod or hole) and how a bond strength from an approval or data sheet compares with this average is set by that document, not by this page. Use it for cross-checks and for reading test results, not for design.
The Fastener & Anchor Pull-Test Report Templates pack has a 40-row proof-test report with automatic PASS/FAIL, ultimate-load statistics, a calibration log, a unit converter, a printable procedure checklist and a standards index. $49 one-time, from Quality Tester Solutions LLC, the company behind Force-Test pull testers.