User Guide

Scenario C

First of all, this is the wrong scenario for on-site testing even if it happens quite often

) Anchor or post-installed rebar performance of different products are compared

on the jobsite via on-site testing by means of comparing the measured load values

of the individual products.

Is that the right scenario for Hilti on-site testing?

The answer is a clear “No”. Taking the wrong conclusions from on-site testing could

compromise the stability of the structure, putting human life at risk and/or lead to

considerable economic consequences.

Why?

Now we have to dig a little bit deeper.

Fundamentally, all types of safety-relevant anchors should be designed in such a

way, that they are resistant and durable under service loads and provide an adequate

margin of safety against failure. Therefore, in the European Union, United States and

other countries, approval processes exist to provide an independent assessment.

Approvals are based on tests intended to verify the suitability of a system and to

determine the admissible service conditions.

Suitability tests are designed to verify the effectiveness of the anchor under

unfavorable application conditions. These tests are generally conducted in concrete

with a strength at the lower and upper end of the usual field of application. Tests in

cracked and uncracked concrete specimens may be chosen, depending on the

intended use of the anchor. The effects of installation variances are checked insofar

as they are relevant. Factors investigated and covered in the approval documents

may include:

• Drill bit tolerances extremes

• Varying technique and effort applied to cleaning the borehole

• Variations in the degree of anchor expansion

• Proximity of the anchor to reinforcing bars

• Variations in the moisture content and temperature in the concrete

• Aggressive/reactive substances.

These tests may account for the influence of sustained and repetitive loads acting on

the anchorage itself as well as the component in which the anchor is placed.

Suitability tests also consider circumstances which may occur while installing the