In post installed anchors with Hilti HIT RE 500 V4 in tension is there a possibility that the anchor fail by pulling out and miss the reinforcement or is there always a concrete cone at the top to intercept the reinforcement?
What would the diameter of the cone be?
It is not clear to me if the code is referring to post installed anchors with epoxy or cast in anchors with heads.
Hello Silvio,
Thank you for reaching out to Hilti.
According to Section 5 of AS5216, concrete cone failure can still occur in the presence of supplementary reinforcement, but the risk is typically reduced. This is because the supplementary reinforcement helps to distribute the load from the anchor over a larger area of concrete, which reduces the likelihood of localized concrete failure and improves the overall strength of the connection.
It is important to note that the diameter of the concrete cone failure will depend on a range of factors, including the specific conditions of the installation, the type and properties of the anchor and adhesive, and the properties of the surrounding concrete. Section 5 Cl (c) also mentions the placement of supplementary reinforcement shall be symmetrical about the fastener and any reinforcement positioned at a distance greater than 0.75hef from the fastener shall be disregarded. Hence, for post-installed anchors, the engineer on the project can use engineering judgment to decide to ignore the concrete breakout calculation based on their knowledge of the reinforced concrete member.
Lastly, AS5216 is specifically referring to post-installed anchors and not to cast-in anchors. Cast-in anchors with heads are usually designed differently and have different failure modes.
Hope this helps.
Kind Regards,
Ask Hilti team
Thanks Mariana for your help.
I would like to check for pull out failure so that I know that the anchor does not pull out without a cone and without intercepting the auxiliary reinforcement. Where can I find the characteristic bond strength of the chemical anchor, say HILTI RE 500V4. Are there any rules of when this failure can occur before cone failure and combined pull out and cone failure. The core does not give much on rule 6.2.4. In combined pull out and cone failure what is the depth and diameter of the cone?
It would be nice if the software would give the three failure values.
Regards