I intend to install 2 column jib cranes in my workshop and the crane manufacturer has specified qty 40 (for both columns) HSL-3 M12/25. The "Base information" provided, details that cracked & non concrete is acceptable. My question is what does Hilti determine to be the acceptable limits of cracking?
Hi Kevin,
Thank you for your question, the distinguish between cracked concrete and non-cracked concrete is quite an important one in a post-installed anchor design. As we know, the determination of cracked concrete conditions are not reliant on a visual inspection for cracks in the concrete but is to do with the stresses in the concrete due to external loads.
Our recommendation is to refer to the relevant standard, which is AS 5216:2018. The standard covers this in section 3.3 Concrete Condition. The section from AS 5216 states that for concrete to be considered uncracked, "No cracking should occur along the entire embedment of the fastener under the characteristic combination of loading at the serviceability limit state condition." For this to be correctly assessed, a stress analysis should be done by the design engineer and it is both our recommendation and the standard to consider cracked concrete conditions unless the assessment is made and uncracked conditions are justified.
We have also addressed a more in depth explanation of cracked vs non-cracked concrete in a previous thread, I would suggest having a look at the link below as well:
https://ask.hilti.com.au/questions/what-is-the-difference-between-cracked-and-uncracked-concrete-and-how-do-i-incorporate-it-into-my-de/n9atv2
I hope this has helped,
Cheers
Tony