A quality control test that measures on site whether an installed anchor or rock bolt carries its design load: axial tension, stepwise loading, displacement record, test report. Done at the request of the specification, the supervising engineer or the client; also on other manufacturers’ anchors.
What it measures
A pull-out test applies an axial tensile load to an anchor or rock bolt installed on site and records its load–displacement behaviour. It answers a single question: does this anchor carry, in this ground, the force assigned to it in the calculation? The drill hole diameter, the grout fill and the bond between bar and ground are assumed in the calculation; the test turns that assumption into a measurement.
Why it is done
| Reason | What is learned |
|---|---|
| Workmanship | That drilling, grouting and bar placement were done to specification |
| Capacity | That the anchor carries enough capacity for the failure mode it was designed for (pull-out, rock or concrete cone breakout, steel failure) |
| Design verification | Whether the ground–grout bond matches the value used in the calculation; correction of the anchor length if needed |
The test alone is not enough: the documents of the anchor bar and of the system (European Technical Assessment, material certificates, corrosion protection) go into the file together with the test.
Who asks for it
- The specification: specifications referring to EN 1537 for ground anchors and EN 14490 for soil nailing give the number of tests and the load.
- The supervising engineer or the client: independent verification before acceptance.
- The contractor: to document its own workmanship; on every anchored line we install we recommend sample testing even when the specification does not require it.
How it is done
A hydraulic jack and a load cell are seated on the anchor head and the displacement is read with a dial gauge; the load is applied in the steps given in the specification, each step is held for the set time, and permanent and elastic displacement are separated. The result is delivered as a load–displacement graph and a test report; the acceptance criterion (test load, permitted displacement) comes from the specification and is not made up on site. The number of tests and the load are included in the anchored slope stabilization specification (Turkish) and the barrier specification (Turkish) texts.
The test report is attached to the "installation" record on the line's barrier tag; in later inspections the anchor head is compared with this record. It is a system-independent service: it is also done on other manufacturers' anchors and bolts. For a quotation, contact.