Anchor testing on construction sites

Fixings installers, main contractors, M&E and façade contractors, and temporary works coordinators: anyone who specifies, installs, tests or relies on anchors drilled into concrete, brick or block. Scaffold tie anchors have their own guidance: see scaffolding.

To find what an anchor can carry: only where the maker has no data for the base material. That is rare in concrete, because BS 8539 recommends anchors with an ETA, and is mostly needed in masonry or where the concrete's condition is in doubt. No tests are needed where an ETA anchor is used in a base material that meets the ETA.

To check the installation (proof tests): not needed where an ETA anchor is designed, selected and installed as its ETA requires, by a competent person under supervision. Otherwise, or where the specifier asks, a sample is proof tested. Some anchors are not usually tested at all: light-duty non-structural plastic anchors, small concrete screws, self-drilling screws, gas and powder-actuated pins, and cast-in bolts and channels. See when to site test anchors.

• The specifier designs the connection, chooses the anchor and sets the test plan, the loads and the factors.
• The installer puts the anchors in as the maker says.
• The tester carries out the tests and reports what happened, without explaining failures unless qualified in anchor technology.
• The specifier or responsible engineer decides what the results mean.

For how this works on a programme with many trades, see anchor testing for contractors.

A fit-out has 600 anchors: 400 in concrete soffits put in by one team, and 200 in a brick wall put in by another. Different base materials and different teams make them two discrete areas, each sampled on its own.

• Concrete soffits: 2.5% of 400 = 10 proof tests.
• Brick wall: 2.5% of 200 = 5 proof tests.
• Total: 15, and each area has at least 3.

At 2.5% the proof factor is 1.5, so an anchor with N_Ek = 2 kN is proof loaded to 3 kN, provided that's no more than 1.5 times the maker's recommended load.

On soffits and walls, fix the rig in place so it can't fall if the anchor fails.

• To 25 kN or 60 kN: a t25 or t60, M6 to M16 or M6 to M20, and threaded adaptors that take the M16 drop rod up to M22, M24, M27 or M30.
• Wider tests: modular bridges with 375 mm or 575 mm between the feet, for preliminary tests and tests to failure where leg spacing matters. See bridge leg spacing.
• Shear: the shear test rig, M6 to M20, with a t25 or t60 load cell.
• Large anchors and rebar: the heavy duty kits, 176 kN and 358 kN. See rebar and holding-down bolts.

Facts that let the specifier judge the tests: the job, the anchor and the test asked for, the base material, how the anchors went in, each anchor's position and result, the tester's equipment and calibration, and a sign-off saying the report records facts only. Use our free anchor test report template, or see what a test report should record.