How does Profis calculate the characteristic tensile strength of a fastener to steel failure (NRk,s)? You can see from page 3 of the attachment that Profis calculated NRk,s = 111 kN for an N16 bar (HIT-RE 500 V3 100 years Rebar 16mm).
According to AS 5216:2021 clause 6.2.2, NRk,s shall be calculated in accordance with AS 4100. Using AS4100 clause 7.2 I have calculated the tensile capacity for an N16 bar as Nt = 86.9 kN (refer to page 10 of the attachment for calculations). I also calculated the tensile capacity of a 16mm dia bolt using clause 9.3.2.2 as Ntf = 84.6 kN (refer to page 10 of the attachment for calculations). However these capacities are both significantly lower than the Profis output of 111 kN.
Hello Hannah,
Thank you for reaching out to Hilti.
As per section 6.2.2 in AS 5216, you can calculate your characteristic tensile steel strength in accordance with AS 4100. However, the capacity reduction factor has to be determined in accordance with Appendix A of AS 5216 and not from AS4100. The difference in the values may be because of the capacity reduction factor. Once you take the values as per AS5216, you will get the resistance values as per section 3.1 in Profis report. Hope the attached snippet from AS5216 clarifies your doubt.
If you’d still like to discuss your design further, please contact our engineering team >> here.
Hope this helps.
Kind Regards,
Ask Hilti team
