How can I check if an anchor has been properly installed?

To check if an anchor has been properly installed you must perform a proof test.

A proof test consists in a tension pull-out test made on an anchor far away from other anchors and from the base material edge.

The minimum sample size shall be 2,5% of the total number of anchors installed, with a minimum of 3 tests. The minimum number of 3 tests applies on each area whether:

• Different anchor might be used


• The base material is different


• The condition of the base material has been affected by different weather conditions (e.g., flooded holes)

The proof test load, N_p, should normally be the characteristic action multiplied by a _Vp,test factor:

N_p = N_{sk Vp,test}

where _Vp,test is 1,5 when 2,5% of the anchors are tested, and 1,25 when 5% of the anchors are tested

If in any discrete area one failure is encountered, the reason for the failure should be investigated, the number of anchors tested in that discrete area should be doubled to 5%, and at least 6.

If more than one anchor fails, then 100% of the anchors should be tested, the reasons for failure determined and the specification reconsidered.

Reasons of failure should be communicated to those responsible for the installation, to avoid further failures on future installations.

For more information, see the standard BS 8539: ”Code of practice for the selection and installation of post-installed anchors in concrete an masonry”, annex B3.

Fort in-situ test equipment, please read FAQ:Quali dispositivi di prova sono consigliati per le prove in situ?