*Posted on behalf of a Hilti customer:
Why does PROFIS Anchor perform “steel failure with lever arm” calculations for applications with stand-off? There are no such provisions in either ACI 318 Appendix D or ACI 318-14 Chapter 17.
Hi Customer,
thank you for your question. PROFIS Anchor utilizes the Guideline for European Technical Approval (ETAG 001) provisions to calculate a steel strength (VsM) to account for bolt bending when a stand-off condition is being modeled for shear load conditions. Calculations are shown in Part 4.2 of the PROFIS Anchor report.
The reason PROFIS Anchor includes this design check is that ACI 318 anchoring-to-concrete provisions do not address the possibility of bolt bending in detail; particularly when the stand-off is not grouted. Therefore, PROFIS Anchor calculations consider bolt bending resulting from a stand-off condition as a possible failure mode in shear because it could be the controlling failure mode when stand-off exists.
When a grouted stand-off condition is being modeled, PROFIS Anchor performs steel failure with lever arm calculations using the ETAG 001 provisions, and shows the results in Part 4.2 of the report. In addition, PROFIS Anchor performs calculations using ACI 318 anchoring-to-concrete provisions for a grouted stand-off condition, and shows the results in Part 4.1 of the report. The 0.8 factor noted in ACI 318 anchoring-to-concrete provisions, which is multiplied by the nominal steel strength in shear (Vsa), is designated Πeb in Part 4.1 of the report.
I hope I have answered your question. If there is anything else, please let me know.
All the best
Justin
Hi Anh,
Information on alpha_m can be found on page 325 of the PROFIS Engineering Design Guide.
Regards,
Emily
Hi Justin,
Unfortunately, this is a limitation of the PROFIS Engineering software. Typically, engineers will do a hand calculation or use other methods to verify the bolt bending capacity. Thank you for the feedback. I will pass it on to our software team.
Regards,
Paris
I would like to request to upgrade the software on these stand off calculations. Provide options for the anchor bolt bending/rotation calculations, like ETAG, EIA-H, any other condition. These lever arm calculations are from European code and we in the US do not need to follow, and it is causing unnecessary stress on design engineers.