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The tension the anchor is designed to carry in service.
Use the same load case the specification's multiplier was written against. A multiplier meant for a service load applied to a factored one, or the reverse, moves the test load by the whole load factor — and the anchor either fails a test it should have passed or passes one that proved nothing.
How many times the design tension the specification asks the test to reach.
Common specified values sit between 1.25 and 2.0, but there is no default worth assuming — the figure belongs to the contract, and inspectors routinely reject a test carried out at the wrong multiplier even when the anchor held.
How many anchors this lot covers — one installer, one product, one condition.
A lot should be homogeneous: the same anchor, the same crew, the same base material and the same day. Sampling across a boundary the specification treats as separate produces a test result that certifies neither group.
The proportion of the lot the specification requires to be tested.
Rates are commonly written as a percentage of the lot with a floor, and are often raised for the first lot or after any failure. Where the specification requires every anchor tested, enter one hundred.
The floor the specification puts under the sample, whatever the percentage gives.
Small lots are why this exists: five per cent of a lot of twelve is one anchor, which is a sample of one and tells you very little. Enter zero if the specification sets no floor.
Proof load to apply and hold
2,700 lbf
The sample rate governs this lot. A proof test demonstrates that the installation holds the specified load without measurable displacement; it is not a capacity test and must not be taken to the anchor's ultimate. Confirm the specification's cap on the applied load, and confirm what counts as a failure and what happens to the rest of the lot when one occurs.
- Anchors to test in this lot
- 6 anchors
- Sample size before the specified floor
- 6 anchors
- Load applied above the design tension
- 899.24 lbf
- Anchors covered by each tested anchor
- 20 anchors
They open the calculator with your figures already in it
Concrete Anchor Proof Load Test Calculator: 2,698 lbf — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- ASTM E488/E488M, Standard Test Methods for Strength of Anchors in Concrete Elements — the reference method for applying and measuring a tension load on an installed anchor
- The proof-load multiplier and the sampling rate are project values, not standard ones: they come from the contract specification and the special inspection programme, which is why both are entered here rather than assumed
- Arithmetic only: proof load = design tension × the specified multiplier; anchors to test = the specified percentage of the lot, rounded up, subject to the specified minimum and never more than the lot holds
Inputs used
- Design Tension per Anchor
- 1798.47 lbf
- Specified Proof-Load Multiplier
- 1.5
- Anchors in the Test Lot
- 120
- Specified Sample Rate
- 5
- Specified Minimum per Lot
- 2
Intermediate steps
- Anchors to test in this lot
- 6 anchors
- Sample size before the specified floor
- 6 anchors
- Load applied above the design tension
- 899.24 lbf
- Anchors covered by each tested anchor
- 20 anchors
Confidence note: The sample rate governs this lot. A proof test demonstrates that the installation holds the specified load without measurable displacement; it is not a capacity test and must not be taken to the anchor's ultimate. Confirm the specification's cap on the applied load, and confirm what counts as a failure and what happens to the rest of the lot when one occurs.
What this calculation does not cover
- Does not set the multiplier or the sample rate. Both are contract values, and a page that supplied them would be inventing the specification.
- Does not check that the proof load is safe to apply. A multiplier taken against a load close to the anchor's capacity can exceed the steel or the concrete during the test itself.
Add the equipment this sizes
This result is a specification — 2,700 lbf — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-09-02 · in the site-wide review of 2026-09-06 · v1.0.1
Regulatory standards & verification citations3
- ASTM E488/E488M, Standard Test Methods for Strength of Anchors in Concrete Elements — the reference method for applying and measuring a tension load on an installed anchor
- The proof-load multiplier and the sampling rate are project values, not standard ones: they come from the contract specification and the special inspection programme, which is why both are entered here rather than assumed
- Arithmetic only: proof load = design tension × the specified multiplier; anchors to test = the specified percentage of the lot, rounded up, subject to the specified minimum and never more than the lot holds
Which documents these citations point at
Standards referenced: ASTM E488 (ASTM International, United States).
Cite this page
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